1 /* $OpenBSD: packet.c,v 1.308 2022/08/31 02:56:40 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_SYNC_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_f("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: %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 struct pollfd pfd; 1329 char buf[8192]; 1330 struct timeval start; 1331 struct timespec timespec, *timespecp = NULL; 1332 1333 DBG(debug("packet_read()")); 1334 1335 /* 1336 * Since we are blocking, ensure that all written packets have 1337 * been sent. 1338 */ 1339 if ((r = ssh_packet_write_wait(ssh)) != 0) 1340 goto out; 1341 1342 /* Stay in the loop until we have received a complete packet. */ 1343 for (;;) { 1344 /* Try to read a packet from the buffer. */ 1345 r = ssh_packet_read_poll_seqnr(ssh, typep, seqnr_p); 1346 if (r != 0) 1347 break; 1348 /* If we got a packet, return it. */ 1349 if (*typep != SSH_MSG_NONE) 1350 break; 1351 /* 1352 * Otherwise, wait for some data to arrive, add it to the 1353 * buffer, and try again. 1354 */ 1355 pfd.fd = state->connection_in; 1356 pfd.events = POLLIN; 1357 1358 if (state->packet_timeout_ms > 0) { 1359 ms_remain = state->packet_timeout_ms; 1360 timespecp = ×pec; 1361 } 1362 /* Wait for some data to arrive. */ 1363 for (;;) { 1364 if (state->packet_timeout_ms > 0) { 1365 ms_to_timespec(×pec, ms_remain); 1366 monotime_tv(&start); 1367 } 1368 if ((r = ppoll(&pfd, 1, timespecp, NULL)) >= 0) 1369 break; 1370 if (errno != EAGAIN && errno != EINTR && 1371 errno != EWOULDBLOCK) { 1372 r = SSH_ERR_SYSTEM_ERROR; 1373 goto out; 1374 } 1375 if (state->packet_timeout_ms <= 0) 1376 continue; 1377 ms_subtract_diff(&start, &ms_remain); 1378 if (ms_remain <= 0) { 1379 r = 0; 1380 break; 1381 } 1382 } 1383 if (r == 0) { 1384 r = SSH_ERR_CONN_TIMEOUT; 1385 goto out; 1386 } 1387 /* Read data from the socket. */ 1388 len = read(state->connection_in, buf, sizeof(buf)); 1389 if (len == 0) { 1390 r = SSH_ERR_CONN_CLOSED; 1391 goto out; 1392 } 1393 if (len == -1) { 1394 r = SSH_ERR_SYSTEM_ERROR; 1395 goto out; 1396 } 1397 1398 /* Append it to the buffer. */ 1399 if ((r = ssh_packet_process_incoming(ssh, buf, len)) != 0) 1400 goto out; 1401 } 1402 out: 1403 return r; 1404 } 1405 1406 int 1407 ssh_packet_read(struct ssh *ssh) 1408 { 1409 u_char type; 1410 int r; 1411 1412 if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0) 1413 fatal_fr(r, "read"); 1414 return type; 1415 } 1416 1417 /* 1418 * Waits until a packet has been received, verifies that its type matches 1419 * that given, and gives a fatal error and exits if there is a mismatch. 1420 */ 1421 1422 int 1423 ssh_packet_read_expect(struct ssh *ssh, u_int expected_type) 1424 { 1425 int r; 1426 u_char type; 1427 1428 if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0) 1429 return r; 1430 if (type != expected_type) { 1431 if ((r = sshpkt_disconnect(ssh, 1432 "Protocol error: expected packet type %d, got %d", 1433 expected_type, type)) != 0) 1434 return r; 1435 return SSH_ERR_PROTOCOL_ERROR; 1436 } 1437 return 0; 1438 } 1439 1440 static int 1441 ssh_packet_read_poll2_mux(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1442 { 1443 struct session_state *state = ssh->state; 1444 const u_char *cp; 1445 size_t need; 1446 int r; 1447 1448 if (ssh->kex) 1449 return SSH_ERR_INTERNAL_ERROR; 1450 *typep = SSH_MSG_NONE; 1451 cp = sshbuf_ptr(state->input); 1452 if (state->packlen == 0) { 1453 if (sshbuf_len(state->input) < 4 + 1) 1454 return 0; /* packet is incomplete */ 1455 state->packlen = PEEK_U32(cp); 1456 if (state->packlen < 4 + 1 || 1457 state->packlen > PACKET_MAX_SIZE) 1458 return SSH_ERR_MESSAGE_INCOMPLETE; 1459 } 1460 need = state->packlen + 4; 1461 if (sshbuf_len(state->input) < need) 1462 return 0; /* packet is incomplete */ 1463 sshbuf_reset(state->incoming_packet); 1464 if ((r = sshbuf_put(state->incoming_packet, cp + 4, 1465 state->packlen)) != 0 || 1466 (r = sshbuf_consume(state->input, need)) != 0 || 1467 (r = sshbuf_get_u8(state->incoming_packet, NULL)) != 0 || 1468 (r = sshbuf_get_u8(state->incoming_packet, typep)) != 0) 1469 return r; 1470 if (ssh_packet_log_type(*typep)) 1471 debug3_f("type %u", *typep); 1472 /* sshbuf_dump(state->incoming_packet, stderr); */ 1473 /* reset for next packet */ 1474 state->packlen = 0; 1475 return r; 1476 } 1477 1478 int 1479 ssh_packet_read_poll2(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1480 { 1481 struct session_state *state = ssh->state; 1482 u_int padlen, need; 1483 u_char *cp; 1484 u_int maclen, aadlen = 0, authlen = 0, block_size; 1485 struct sshenc *enc = NULL; 1486 struct sshmac *mac = NULL; 1487 struct sshcomp *comp = NULL; 1488 int r; 1489 1490 if (state->mux) 1491 return ssh_packet_read_poll2_mux(ssh, typep, seqnr_p); 1492 1493 *typep = SSH_MSG_NONE; 1494 1495 if (state->packet_discard) 1496 return 0; 1497 1498 if (state->newkeys[MODE_IN] != NULL) { 1499 enc = &state->newkeys[MODE_IN]->enc; 1500 mac = &state->newkeys[MODE_IN]->mac; 1501 comp = &state->newkeys[MODE_IN]->comp; 1502 /* disable mac for authenticated encryption */ 1503 if ((authlen = cipher_authlen(enc->cipher)) != 0) 1504 mac = NULL; 1505 } 1506 maclen = mac && mac->enabled ? mac->mac_len : 0; 1507 block_size = enc ? enc->block_size : 8; 1508 aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0; 1509 1510 if (aadlen && state->packlen == 0) { 1511 if (cipher_get_length(state->receive_context, 1512 &state->packlen, state->p_read.seqnr, 1513 sshbuf_ptr(state->input), sshbuf_len(state->input)) != 0) 1514 return 0; 1515 if (state->packlen < 1 + 4 || 1516 state->packlen > PACKET_MAX_SIZE) { 1517 #ifdef PACKET_DEBUG 1518 sshbuf_dump(state->input, stderr); 1519 #endif 1520 logit("Bad packet length %u.", state->packlen); 1521 if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0) 1522 return r; 1523 return SSH_ERR_CONN_CORRUPT; 1524 } 1525 sshbuf_reset(state->incoming_packet); 1526 } else if (state->packlen == 0) { 1527 /* 1528 * check if input size is less than the cipher block size, 1529 * decrypt first block and extract length of incoming packet 1530 */ 1531 if (sshbuf_len(state->input) < block_size) 1532 return 0; 1533 sshbuf_reset(state->incoming_packet); 1534 if ((r = sshbuf_reserve(state->incoming_packet, block_size, 1535 &cp)) != 0) 1536 goto out; 1537 if ((r = cipher_crypt(state->receive_context, 1538 state->p_send.seqnr, cp, sshbuf_ptr(state->input), 1539 block_size, 0, 0)) != 0) 1540 goto out; 1541 state->packlen = PEEK_U32(sshbuf_ptr(state->incoming_packet)); 1542 if (state->packlen < 1 + 4 || 1543 state->packlen > PACKET_MAX_SIZE) { 1544 #ifdef PACKET_DEBUG 1545 fprintf(stderr, "input: \n"); 1546 sshbuf_dump(state->input, stderr); 1547 fprintf(stderr, "incoming_packet: \n"); 1548 sshbuf_dump(state->incoming_packet, stderr); 1549 #endif 1550 logit("Bad packet length %u.", state->packlen); 1551 return ssh_packet_start_discard(ssh, enc, mac, 0, 1552 PACKET_MAX_SIZE); 1553 } 1554 if ((r = sshbuf_consume(state->input, block_size)) != 0) 1555 goto out; 1556 } 1557 DBG(debug("input: packet len %u", state->packlen+4)); 1558 1559 if (aadlen) { 1560 /* only the payload is encrypted */ 1561 need = state->packlen; 1562 } else { 1563 /* 1564 * the payload size and the payload are encrypted, but we 1565 * have a partial packet of block_size bytes 1566 */ 1567 need = 4 + state->packlen - block_size; 1568 } 1569 DBG(debug("partial packet: block %d, need %d, maclen %d, authlen %d," 1570 " aadlen %d", block_size, need, maclen, authlen, aadlen)); 1571 if (need % block_size != 0) { 1572 logit("padding error: need %d block %d mod %d", 1573 need, block_size, need % block_size); 1574 return ssh_packet_start_discard(ssh, enc, mac, 0, 1575 PACKET_MAX_SIZE - block_size); 1576 } 1577 /* 1578 * check if the entire packet has been received and 1579 * decrypt into incoming_packet: 1580 * 'aadlen' bytes are unencrypted, but authenticated. 1581 * 'need' bytes are encrypted, followed by either 1582 * 'authlen' bytes of authentication tag or 1583 * 'maclen' bytes of message authentication code. 1584 */ 1585 if (sshbuf_len(state->input) < aadlen + need + authlen + maclen) 1586 return 0; /* packet is incomplete */ 1587 #ifdef PACKET_DEBUG 1588 fprintf(stderr, "read_poll enc/full: "); 1589 sshbuf_dump(state->input, stderr); 1590 #endif 1591 /* EtM: check mac over encrypted input */ 1592 if (mac && mac->enabled && mac->etm) { 1593 if ((r = mac_check(mac, state->p_read.seqnr, 1594 sshbuf_ptr(state->input), aadlen + need, 1595 sshbuf_ptr(state->input) + aadlen + need + authlen, 1596 maclen)) != 0) { 1597 if (r == SSH_ERR_MAC_INVALID) 1598 logit("Corrupted MAC on input."); 1599 goto out; 1600 } 1601 } 1602 if ((r = sshbuf_reserve(state->incoming_packet, aadlen + need, 1603 &cp)) != 0) 1604 goto out; 1605 if ((r = cipher_crypt(state->receive_context, state->p_read.seqnr, cp, 1606 sshbuf_ptr(state->input), need, aadlen, authlen)) != 0) 1607 goto out; 1608 if ((r = sshbuf_consume(state->input, aadlen + need + authlen)) != 0) 1609 goto out; 1610 if (mac && mac->enabled) { 1611 /* Not EtM: check MAC over cleartext */ 1612 if (!mac->etm && (r = mac_check(mac, state->p_read.seqnr, 1613 sshbuf_ptr(state->incoming_packet), 1614 sshbuf_len(state->incoming_packet), 1615 sshbuf_ptr(state->input), maclen)) != 0) { 1616 if (r != SSH_ERR_MAC_INVALID) 1617 goto out; 1618 logit("Corrupted MAC on input."); 1619 if (need + block_size > PACKET_MAX_SIZE) 1620 return SSH_ERR_INTERNAL_ERROR; 1621 return ssh_packet_start_discard(ssh, enc, mac, 1622 sshbuf_len(state->incoming_packet), 1623 PACKET_MAX_SIZE - need - block_size); 1624 } 1625 /* Remove MAC from input buffer */ 1626 DBG(debug("MAC #%d ok", state->p_read.seqnr)); 1627 if ((r = sshbuf_consume(state->input, mac->mac_len)) != 0) 1628 goto out; 1629 } 1630 if (seqnr_p != NULL) 1631 *seqnr_p = state->p_read.seqnr; 1632 if (++state->p_read.seqnr == 0) 1633 logit("incoming seqnr wraps around"); 1634 if (++state->p_read.packets == 0) 1635 if (!(ssh->compat & SSH_BUG_NOREKEY)) 1636 return SSH_ERR_NEED_REKEY; 1637 state->p_read.blocks += (state->packlen + 4) / block_size; 1638 state->p_read.bytes += state->packlen + 4; 1639 1640 /* get padlen */ 1641 padlen = sshbuf_ptr(state->incoming_packet)[4]; 1642 DBG(debug("input: padlen %d", padlen)); 1643 if (padlen < 4) { 1644 if ((r = sshpkt_disconnect(ssh, 1645 "Corrupted padlen %d on input.", padlen)) != 0 || 1646 (r = ssh_packet_write_wait(ssh)) != 0) 1647 return r; 1648 return SSH_ERR_CONN_CORRUPT; 1649 } 1650 1651 /* skip packet size + padlen, discard padding */ 1652 if ((r = sshbuf_consume(state->incoming_packet, 4 + 1)) != 0 || 1653 ((r = sshbuf_consume_end(state->incoming_packet, padlen)) != 0)) 1654 goto out; 1655 1656 DBG(debug("input: len before de-compress %zd", 1657 sshbuf_len(state->incoming_packet))); 1658 if (comp && comp->enabled) { 1659 sshbuf_reset(state->compression_buffer); 1660 if ((r = uncompress_buffer(ssh, state->incoming_packet, 1661 state->compression_buffer)) != 0) 1662 goto out; 1663 sshbuf_reset(state->incoming_packet); 1664 if ((r = sshbuf_putb(state->incoming_packet, 1665 state->compression_buffer)) != 0) 1666 goto out; 1667 DBG(debug("input: len after de-compress %zd", 1668 sshbuf_len(state->incoming_packet))); 1669 } 1670 /* 1671 * get packet type, implies consume. 1672 * return length of payload (without type field) 1673 */ 1674 if ((r = sshbuf_get_u8(state->incoming_packet, typep)) != 0) 1675 goto out; 1676 if (ssh_packet_log_type(*typep)) 1677 debug3("receive packet: type %u", *typep); 1678 if (*typep < SSH2_MSG_MIN || *typep >= SSH2_MSG_LOCAL_MIN) { 1679 if ((r = sshpkt_disconnect(ssh, 1680 "Invalid ssh2 packet type: %d", *typep)) != 0 || 1681 (r = ssh_packet_write_wait(ssh)) != 0) 1682 return r; 1683 return SSH_ERR_PROTOCOL_ERROR; 1684 } 1685 if (state->hook_in != NULL && 1686 (r = state->hook_in(ssh, state->incoming_packet, typep, 1687 state->hook_in_ctx)) != 0) 1688 return r; 1689 if (*typep == SSH2_MSG_USERAUTH_SUCCESS && !state->server_side) 1690 r = ssh_packet_enable_delayed_compress(ssh); 1691 else 1692 r = 0; 1693 #ifdef PACKET_DEBUG 1694 fprintf(stderr, "read/plain[%d]:\r\n", *typep); 1695 sshbuf_dump(state->incoming_packet, stderr); 1696 #endif 1697 /* reset for next packet */ 1698 state->packlen = 0; 1699 1700 if ((r = ssh_packet_check_rekey(ssh)) != 0) 1701 return r; 1702 out: 1703 return r; 1704 } 1705 1706 int 1707 ssh_packet_read_poll_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1708 { 1709 struct session_state *state = ssh->state; 1710 u_int reason, seqnr; 1711 int r; 1712 u_char *msg; 1713 1714 for (;;) { 1715 msg = NULL; 1716 r = ssh_packet_read_poll2(ssh, typep, seqnr_p); 1717 if (r != 0) 1718 return r; 1719 if (*typep) { 1720 state->keep_alive_timeouts = 0; 1721 DBG(debug("received packet type %d", *typep)); 1722 } 1723 switch (*typep) { 1724 case SSH2_MSG_IGNORE: 1725 debug3("Received SSH2_MSG_IGNORE"); 1726 break; 1727 case SSH2_MSG_DEBUG: 1728 if ((r = sshpkt_get_u8(ssh, NULL)) != 0 || 1729 (r = sshpkt_get_string(ssh, &msg, NULL)) != 0 || 1730 (r = sshpkt_get_string(ssh, NULL, NULL)) != 0) { 1731 free(msg); 1732 return r; 1733 } 1734 debug("Remote: %.900s", msg); 1735 free(msg); 1736 break; 1737 case SSH2_MSG_DISCONNECT: 1738 if ((r = sshpkt_get_u32(ssh, &reason)) != 0 || 1739 (r = sshpkt_get_string(ssh, &msg, NULL)) != 0) 1740 return r; 1741 /* Ignore normal client exit notifications */ 1742 do_log2(ssh->state->server_side && 1743 reason == SSH2_DISCONNECT_BY_APPLICATION ? 1744 SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_ERROR, 1745 "Received disconnect from %s port %d:" 1746 "%u: %.400s", ssh_remote_ipaddr(ssh), 1747 ssh_remote_port(ssh), reason, msg); 1748 free(msg); 1749 return SSH_ERR_DISCONNECTED; 1750 case SSH2_MSG_UNIMPLEMENTED: 1751 if ((r = sshpkt_get_u32(ssh, &seqnr)) != 0) 1752 return r; 1753 debug("Received SSH2_MSG_UNIMPLEMENTED for %u", 1754 seqnr); 1755 break; 1756 default: 1757 return 0; 1758 } 1759 } 1760 } 1761 1762 /* 1763 * Buffers the supplied input data. This is intended to be used together 1764 * with packet_read_poll(). 1765 */ 1766 int 1767 ssh_packet_process_incoming(struct ssh *ssh, const char *buf, u_int len) 1768 { 1769 struct session_state *state = ssh->state; 1770 int r; 1771 1772 if (state->packet_discard) { 1773 state->keep_alive_timeouts = 0; /* ?? */ 1774 if (len >= state->packet_discard) { 1775 if ((r = ssh_packet_stop_discard(ssh)) != 0) 1776 return r; 1777 } 1778 state->packet_discard -= len; 1779 return 0; 1780 } 1781 if ((r = sshbuf_put(state->input, buf, len)) != 0) 1782 return r; 1783 1784 return 0; 1785 } 1786 1787 /* Reads and buffers data from the specified fd */ 1788 int 1789 ssh_packet_process_read(struct ssh *ssh, int fd) 1790 { 1791 struct session_state *state = ssh->state; 1792 int r; 1793 size_t rlen; 1794 1795 if ((r = sshbuf_read(fd, state->input, PACKET_MAX_SIZE, &rlen)) != 0) 1796 return r; 1797 1798 if (state->packet_discard) { 1799 if ((r = sshbuf_consume_end(state->input, rlen)) != 0) 1800 return r; 1801 state->keep_alive_timeouts = 0; /* ?? */ 1802 if (rlen >= state->packet_discard) { 1803 if ((r = ssh_packet_stop_discard(ssh)) != 0) 1804 return r; 1805 } 1806 state->packet_discard -= rlen; 1807 return 0; 1808 } 1809 return 0; 1810 } 1811 1812 int 1813 ssh_packet_remaining(struct ssh *ssh) 1814 { 1815 return sshbuf_len(ssh->state->incoming_packet); 1816 } 1817 1818 /* 1819 * Sends a diagnostic message from the server to the client. This message 1820 * can be sent at any time (but not while constructing another message). The 1821 * message is printed immediately, but only if the client is being executed 1822 * in verbose mode. These messages are primarily intended to ease debugging 1823 * authentication problems. The length of the formatted message must not 1824 * exceed 1024 bytes. This will automatically call ssh_packet_write_wait. 1825 */ 1826 void 1827 ssh_packet_send_debug(struct ssh *ssh, const char *fmt,...) 1828 { 1829 char buf[1024]; 1830 va_list args; 1831 int r; 1832 1833 if ((ssh->compat & SSH_BUG_DEBUG)) 1834 return; 1835 1836 va_start(args, fmt); 1837 vsnprintf(buf, sizeof(buf), fmt, args); 1838 va_end(args); 1839 1840 debug3("sending debug message: %s", buf); 1841 1842 if ((r = sshpkt_start(ssh, SSH2_MSG_DEBUG)) != 0 || 1843 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* always display */ 1844 (r = sshpkt_put_cstring(ssh, buf)) != 0 || 1845 (r = sshpkt_put_cstring(ssh, "")) != 0 || 1846 (r = sshpkt_send(ssh)) != 0 || 1847 (r = ssh_packet_write_wait(ssh)) != 0) 1848 fatal_fr(r, "send DEBUG"); 1849 } 1850 1851 void 1852 sshpkt_fmt_connection_id(struct ssh *ssh, char *s, size_t l) 1853 { 1854 snprintf(s, l, "%.200s%s%s port %d", 1855 ssh->log_preamble ? ssh->log_preamble : "", 1856 ssh->log_preamble ? " " : "", 1857 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 1858 } 1859 1860 /* 1861 * Pretty-print connection-terminating errors and exit. 1862 */ 1863 static void 1864 sshpkt_vfatal(struct ssh *ssh, int r, const char *fmt, va_list ap) 1865 { 1866 char *tag = NULL, remote_id[512]; 1867 int oerrno = errno; 1868 1869 sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id)); 1870 1871 switch (r) { 1872 case SSH_ERR_CONN_CLOSED: 1873 ssh_packet_clear_keys(ssh); 1874 logdie("Connection closed by %s", remote_id); 1875 case SSH_ERR_CONN_TIMEOUT: 1876 ssh_packet_clear_keys(ssh); 1877 logdie("Connection %s %s timed out", 1878 ssh->state->server_side ? "from" : "to", remote_id); 1879 case SSH_ERR_DISCONNECTED: 1880 ssh_packet_clear_keys(ssh); 1881 logdie("Disconnected from %s", remote_id); 1882 case SSH_ERR_SYSTEM_ERROR: 1883 if (errno == ECONNRESET) { 1884 ssh_packet_clear_keys(ssh); 1885 logdie("Connection reset by %s", remote_id); 1886 } 1887 /* FALLTHROUGH */ 1888 case SSH_ERR_NO_CIPHER_ALG_MATCH: 1889 case SSH_ERR_NO_MAC_ALG_MATCH: 1890 case SSH_ERR_NO_COMPRESS_ALG_MATCH: 1891 case SSH_ERR_NO_KEX_ALG_MATCH: 1892 case SSH_ERR_NO_HOSTKEY_ALG_MATCH: 1893 if (ssh && ssh->kex && ssh->kex->failed_choice) { 1894 ssh_packet_clear_keys(ssh); 1895 errno = oerrno; 1896 logdie("Unable to negotiate with %s: %s. " 1897 "Their offer: %s", remote_id, ssh_err(r), 1898 ssh->kex->failed_choice); 1899 } 1900 /* FALLTHROUGH */ 1901 default: 1902 if (vasprintf(&tag, fmt, ap) == -1) { 1903 ssh_packet_clear_keys(ssh); 1904 logdie_f("could not allocate failure message"); 1905 } 1906 ssh_packet_clear_keys(ssh); 1907 errno = oerrno; 1908 logdie_r(r, "%s%sConnection %s %s", 1909 tag != NULL ? tag : "", tag != NULL ? ": " : "", 1910 ssh->state->server_side ? "from" : "to", remote_id); 1911 } 1912 } 1913 1914 void 1915 sshpkt_fatal(struct ssh *ssh, int r, const char *fmt, ...) 1916 { 1917 va_list ap; 1918 1919 va_start(ap, fmt); 1920 sshpkt_vfatal(ssh, r, fmt, ap); 1921 /* NOTREACHED */ 1922 va_end(ap); 1923 logdie_f("should have exited"); 1924 } 1925 1926 /* 1927 * Logs the error plus constructs and sends a disconnect packet, closes the 1928 * connection, and exits. This function never returns. The error message 1929 * should not contain a newline. The length of the formatted message must 1930 * not exceed 1024 bytes. 1931 */ 1932 void 1933 ssh_packet_disconnect(struct ssh *ssh, const char *fmt,...) 1934 { 1935 char buf[1024], remote_id[512]; 1936 va_list args; 1937 static int disconnecting = 0; 1938 int r; 1939 1940 if (disconnecting) /* Guard against recursive invocations. */ 1941 fatal("packet_disconnect called recursively."); 1942 disconnecting = 1; 1943 1944 /* 1945 * Format the message. Note that the caller must make sure the 1946 * message is of limited size. 1947 */ 1948 sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id)); 1949 va_start(args, fmt); 1950 vsnprintf(buf, sizeof(buf), fmt, args); 1951 va_end(args); 1952 1953 /* Display the error locally */ 1954 logit("Disconnecting %s: %.100s", remote_id, buf); 1955 1956 /* 1957 * Send the disconnect message to the other side, and wait 1958 * for it to get sent. 1959 */ 1960 if ((r = sshpkt_disconnect(ssh, "%s", buf)) != 0) 1961 sshpkt_fatal(ssh, r, "%s", __func__); 1962 1963 if ((r = ssh_packet_write_wait(ssh)) != 0) 1964 sshpkt_fatal(ssh, r, "%s", __func__); 1965 1966 /* Close the connection. */ 1967 ssh_packet_close(ssh); 1968 cleanup_exit(255); 1969 } 1970 1971 /* 1972 * Checks if there is any buffered output, and tries to write some of 1973 * the output. 1974 */ 1975 int 1976 ssh_packet_write_poll(struct ssh *ssh) 1977 { 1978 struct session_state *state = ssh->state; 1979 int len = sshbuf_len(state->output); 1980 int r; 1981 1982 if (len > 0) { 1983 len = write(state->connection_out, 1984 sshbuf_ptr(state->output), len); 1985 if (len == -1) { 1986 if (errno == EINTR || errno == EAGAIN || 1987 errno == EWOULDBLOCK) 1988 return 0; 1989 return SSH_ERR_SYSTEM_ERROR; 1990 } 1991 if (len == 0) 1992 return SSH_ERR_CONN_CLOSED; 1993 if ((r = sshbuf_consume(state->output, len)) != 0) 1994 return r; 1995 } 1996 return 0; 1997 } 1998 1999 /* 2000 * Calls packet_write_poll repeatedly until all pending output data has been 2001 * written. 2002 */ 2003 int 2004 ssh_packet_write_wait(struct ssh *ssh) 2005 { 2006 int ret, r, ms_remain = 0; 2007 struct timeval start; 2008 struct timespec timespec, *timespecp = NULL; 2009 struct session_state *state = ssh->state; 2010 struct pollfd pfd; 2011 2012 if ((r = ssh_packet_write_poll(ssh)) != 0) 2013 return r; 2014 while (ssh_packet_have_data_to_write(ssh)) { 2015 pfd.fd = state->connection_out; 2016 pfd.events = POLLOUT; 2017 2018 if (state->packet_timeout_ms > 0) { 2019 ms_remain = state->packet_timeout_ms; 2020 timespecp = ×pec; 2021 } 2022 for (;;) { 2023 if (state->packet_timeout_ms > 0) { 2024 ms_to_timespec(×pec, ms_remain); 2025 monotime_tv(&start); 2026 } 2027 if ((ret = ppoll(&pfd, 1, timespecp, NULL)) >= 0) 2028 break; 2029 if (errno != EAGAIN && errno != EINTR && 2030 errno != EWOULDBLOCK) 2031 break; 2032 if (state->packet_timeout_ms <= 0) 2033 continue; 2034 ms_subtract_diff(&start, &ms_remain); 2035 if (ms_remain <= 0) { 2036 ret = 0; 2037 break; 2038 } 2039 } 2040 if (ret == 0) 2041 return SSH_ERR_CONN_TIMEOUT; 2042 if ((r = ssh_packet_write_poll(ssh)) != 0) 2043 return r; 2044 } 2045 return 0; 2046 } 2047 2048 /* Returns true if there is buffered data to write to the connection. */ 2049 2050 int 2051 ssh_packet_have_data_to_write(struct ssh *ssh) 2052 { 2053 return sshbuf_len(ssh->state->output) != 0; 2054 } 2055 2056 /* Returns true if there is not too much data to write to the connection. */ 2057 2058 int 2059 ssh_packet_not_very_much_data_to_write(struct ssh *ssh) 2060 { 2061 if (ssh->state->interactive_mode) 2062 return sshbuf_len(ssh->state->output) < 16384; 2063 else 2064 return sshbuf_len(ssh->state->output) < 128 * 1024; 2065 } 2066 2067 void 2068 ssh_packet_set_tos(struct ssh *ssh, int tos) 2069 { 2070 if (!ssh_packet_connection_is_on_socket(ssh) || tos == INT_MAX) 2071 return; 2072 set_sock_tos(ssh->state->connection_in, tos); 2073 } 2074 2075 /* Informs that the current session is interactive. Sets IP flags for that. */ 2076 2077 void 2078 ssh_packet_set_interactive(struct ssh *ssh, int interactive, int qos_interactive, int qos_bulk) 2079 { 2080 struct session_state *state = ssh->state; 2081 2082 if (state->set_interactive_called) 2083 return; 2084 state->set_interactive_called = 1; 2085 2086 /* Record that we are in interactive mode. */ 2087 state->interactive_mode = interactive; 2088 2089 /* Only set socket options if using a socket. */ 2090 if (!ssh_packet_connection_is_on_socket(ssh)) 2091 return; 2092 set_nodelay(state->connection_in); 2093 ssh_packet_set_tos(ssh, interactive ? qos_interactive : qos_bulk); 2094 } 2095 2096 /* Returns true if the current connection is interactive. */ 2097 2098 int 2099 ssh_packet_is_interactive(struct ssh *ssh) 2100 { 2101 return ssh->state->interactive_mode; 2102 } 2103 2104 int 2105 ssh_packet_set_maxsize(struct ssh *ssh, u_int s) 2106 { 2107 struct session_state *state = ssh->state; 2108 2109 if (state->set_maxsize_called) { 2110 logit_f("called twice: old %d new %d", 2111 state->max_packet_size, s); 2112 return -1; 2113 } 2114 if (s < 4 * 1024 || s > 1024 * 1024) { 2115 logit_f("bad size %d", s); 2116 return -1; 2117 } 2118 state->set_maxsize_called = 1; 2119 debug_f("setting to %d", s); 2120 state->max_packet_size = s; 2121 return s; 2122 } 2123 2124 int 2125 ssh_packet_inc_alive_timeouts(struct ssh *ssh) 2126 { 2127 return ++ssh->state->keep_alive_timeouts; 2128 } 2129 2130 void 2131 ssh_packet_set_alive_timeouts(struct ssh *ssh, int ka) 2132 { 2133 ssh->state->keep_alive_timeouts = ka; 2134 } 2135 2136 u_int 2137 ssh_packet_get_maxsize(struct ssh *ssh) 2138 { 2139 return ssh->state->max_packet_size; 2140 } 2141 2142 void 2143 ssh_packet_set_rekey_limits(struct ssh *ssh, u_int64_t bytes, u_int32_t seconds) 2144 { 2145 debug3("rekey after %llu bytes, %u seconds", (unsigned long long)bytes, 2146 (unsigned int)seconds); 2147 ssh->state->rekey_limit = bytes; 2148 ssh->state->rekey_interval = seconds; 2149 } 2150 2151 time_t 2152 ssh_packet_get_rekey_timeout(struct ssh *ssh) 2153 { 2154 time_t seconds; 2155 2156 seconds = ssh->state->rekey_time + ssh->state->rekey_interval - 2157 monotime(); 2158 return (seconds <= 0 ? 1 : seconds); 2159 } 2160 2161 void 2162 ssh_packet_set_server(struct ssh *ssh) 2163 { 2164 ssh->state->server_side = 1; 2165 ssh->kex->server = 1; /* XXX unify? */ 2166 } 2167 2168 void 2169 ssh_packet_set_authenticated(struct ssh *ssh) 2170 { 2171 ssh->state->after_authentication = 1; 2172 } 2173 2174 void * 2175 ssh_packet_get_input(struct ssh *ssh) 2176 { 2177 return (void *)ssh->state->input; 2178 } 2179 2180 void * 2181 ssh_packet_get_output(struct ssh *ssh) 2182 { 2183 return (void *)ssh->state->output; 2184 } 2185 2186 /* Reset after_authentication and reset compression in post-auth privsep */ 2187 static int 2188 ssh_packet_set_postauth(struct ssh *ssh) 2189 { 2190 int r; 2191 2192 debug_f("called"); 2193 /* This was set in net child, but is not visible in user child */ 2194 ssh->state->after_authentication = 1; 2195 ssh->state->rekeying = 0; 2196 if ((r = ssh_packet_enable_delayed_compress(ssh)) != 0) 2197 return r; 2198 return 0; 2199 } 2200 2201 /* Packet state (de-)serialization for privsep */ 2202 2203 /* turn kex into a blob for packet state serialization */ 2204 static int 2205 kex_to_blob(struct sshbuf *m, struct kex *kex) 2206 { 2207 int r; 2208 2209 if ((r = sshbuf_put_u32(m, kex->we_need)) != 0 || 2210 (r = sshbuf_put_cstring(m, kex->hostkey_alg)) != 0 || 2211 (r = sshbuf_put_u32(m, kex->hostkey_type)) != 0 || 2212 (r = sshbuf_put_u32(m, kex->hostkey_nid)) != 0 || 2213 (r = sshbuf_put_u32(m, kex->kex_type)) != 0 || 2214 (r = sshbuf_put_stringb(m, kex->my)) != 0 || 2215 (r = sshbuf_put_stringb(m, kex->peer)) != 0 || 2216 (r = sshbuf_put_stringb(m, kex->client_version)) != 0 || 2217 (r = sshbuf_put_stringb(m, kex->server_version)) != 0 || 2218 (r = sshbuf_put_stringb(m, kex->session_id)) != 0 || 2219 (r = sshbuf_put_u32(m, kex->flags)) != 0) 2220 return r; 2221 return 0; 2222 } 2223 2224 /* turn key exchange results into a blob for packet state serialization */ 2225 static int 2226 newkeys_to_blob(struct sshbuf *m, struct ssh *ssh, int mode) 2227 { 2228 struct sshbuf *b; 2229 struct sshcipher_ctx *cc; 2230 struct sshcomp *comp; 2231 struct sshenc *enc; 2232 struct sshmac *mac; 2233 struct newkeys *newkey; 2234 int r; 2235 2236 if ((newkey = ssh->state->newkeys[mode]) == NULL) 2237 return SSH_ERR_INTERNAL_ERROR; 2238 enc = &newkey->enc; 2239 mac = &newkey->mac; 2240 comp = &newkey->comp; 2241 cc = (mode == MODE_OUT) ? ssh->state->send_context : 2242 ssh->state->receive_context; 2243 if ((r = cipher_get_keyiv(cc, enc->iv, enc->iv_len)) != 0) 2244 return r; 2245 if ((b = sshbuf_new()) == NULL) 2246 return SSH_ERR_ALLOC_FAIL; 2247 if ((r = sshbuf_put_cstring(b, enc->name)) != 0 || 2248 (r = sshbuf_put_u32(b, enc->enabled)) != 0 || 2249 (r = sshbuf_put_u32(b, enc->block_size)) != 0 || 2250 (r = sshbuf_put_string(b, enc->key, enc->key_len)) != 0 || 2251 (r = sshbuf_put_string(b, enc->iv, enc->iv_len)) != 0) 2252 goto out; 2253 if (cipher_authlen(enc->cipher) == 0) { 2254 if ((r = sshbuf_put_cstring(b, mac->name)) != 0 || 2255 (r = sshbuf_put_u32(b, mac->enabled)) != 0 || 2256 (r = sshbuf_put_string(b, mac->key, mac->key_len)) != 0) 2257 goto out; 2258 } 2259 if ((r = sshbuf_put_u32(b, comp->type)) != 0 || 2260 (r = sshbuf_put_cstring(b, comp->name)) != 0) 2261 goto out; 2262 r = sshbuf_put_stringb(m, b); 2263 out: 2264 sshbuf_free(b); 2265 return r; 2266 } 2267 2268 /* serialize packet state into a blob */ 2269 int 2270 ssh_packet_get_state(struct ssh *ssh, struct sshbuf *m) 2271 { 2272 struct session_state *state = ssh->state; 2273 int r; 2274 2275 if ((r = kex_to_blob(m, ssh->kex)) != 0 || 2276 (r = newkeys_to_blob(m, ssh, MODE_OUT)) != 0 || 2277 (r = newkeys_to_blob(m, ssh, MODE_IN)) != 0 || 2278 (r = sshbuf_put_u64(m, state->rekey_limit)) != 0 || 2279 (r = sshbuf_put_u32(m, state->rekey_interval)) != 0 || 2280 (r = sshbuf_put_u32(m, state->p_send.seqnr)) != 0 || 2281 (r = sshbuf_put_u64(m, state->p_send.blocks)) != 0 || 2282 (r = sshbuf_put_u32(m, state->p_send.packets)) != 0 || 2283 (r = sshbuf_put_u64(m, state->p_send.bytes)) != 0 || 2284 (r = sshbuf_put_u32(m, state->p_read.seqnr)) != 0 || 2285 (r = sshbuf_put_u64(m, state->p_read.blocks)) != 0 || 2286 (r = sshbuf_put_u32(m, state->p_read.packets)) != 0 || 2287 (r = sshbuf_put_u64(m, state->p_read.bytes)) != 0 || 2288 (r = sshbuf_put_stringb(m, state->input)) != 0 || 2289 (r = sshbuf_put_stringb(m, state->output)) != 0) 2290 return r; 2291 2292 return 0; 2293 } 2294 2295 /* restore key exchange results from blob for packet state de-serialization */ 2296 static int 2297 newkeys_from_blob(struct sshbuf *m, struct ssh *ssh, int mode) 2298 { 2299 struct sshbuf *b = NULL; 2300 struct sshcomp *comp; 2301 struct sshenc *enc; 2302 struct sshmac *mac; 2303 struct newkeys *newkey = NULL; 2304 size_t keylen, ivlen, maclen; 2305 int r; 2306 2307 if ((newkey = calloc(1, sizeof(*newkey))) == NULL) { 2308 r = SSH_ERR_ALLOC_FAIL; 2309 goto out; 2310 } 2311 if ((r = sshbuf_froms(m, &b)) != 0) 2312 goto out; 2313 #ifdef DEBUG_PK 2314 sshbuf_dump(b, stderr); 2315 #endif 2316 enc = &newkey->enc; 2317 mac = &newkey->mac; 2318 comp = &newkey->comp; 2319 2320 if ((r = sshbuf_get_cstring(b, &enc->name, NULL)) != 0 || 2321 (r = sshbuf_get_u32(b, (u_int *)&enc->enabled)) != 0 || 2322 (r = sshbuf_get_u32(b, &enc->block_size)) != 0 || 2323 (r = sshbuf_get_string(b, &enc->key, &keylen)) != 0 || 2324 (r = sshbuf_get_string(b, &enc->iv, &ivlen)) != 0) 2325 goto out; 2326 if ((enc->cipher = cipher_by_name(enc->name)) == NULL) { 2327 r = SSH_ERR_INVALID_FORMAT; 2328 goto out; 2329 } 2330 if (cipher_authlen(enc->cipher) == 0) { 2331 if ((r = sshbuf_get_cstring(b, &mac->name, NULL)) != 0) 2332 goto out; 2333 if ((r = mac_setup(mac, mac->name)) != 0) 2334 goto out; 2335 if ((r = sshbuf_get_u32(b, (u_int *)&mac->enabled)) != 0 || 2336 (r = sshbuf_get_string(b, &mac->key, &maclen)) != 0) 2337 goto out; 2338 if (maclen > mac->key_len) { 2339 r = SSH_ERR_INVALID_FORMAT; 2340 goto out; 2341 } 2342 mac->key_len = maclen; 2343 } 2344 if ((r = sshbuf_get_u32(b, &comp->type)) != 0 || 2345 (r = sshbuf_get_cstring(b, &comp->name, NULL)) != 0) 2346 goto out; 2347 if (sshbuf_len(b) != 0) { 2348 r = SSH_ERR_INVALID_FORMAT; 2349 goto out; 2350 } 2351 enc->key_len = keylen; 2352 enc->iv_len = ivlen; 2353 ssh->kex->newkeys[mode] = newkey; 2354 newkey = NULL; 2355 r = 0; 2356 out: 2357 free(newkey); 2358 sshbuf_free(b); 2359 return r; 2360 } 2361 2362 /* restore kex from blob for packet state de-serialization */ 2363 static int 2364 kex_from_blob(struct sshbuf *m, struct kex **kexp) 2365 { 2366 struct kex *kex; 2367 int r; 2368 2369 if ((kex = kex_new()) == NULL) 2370 return SSH_ERR_ALLOC_FAIL; 2371 if ((r = sshbuf_get_u32(m, &kex->we_need)) != 0 || 2372 (r = sshbuf_get_cstring(m, &kex->hostkey_alg, NULL)) != 0 || 2373 (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_type)) != 0 || 2374 (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_nid)) != 0 || 2375 (r = sshbuf_get_u32(m, &kex->kex_type)) != 0 || 2376 (r = sshbuf_get_stringb(m, kex->my)) != 0 || 2377 (r = sshbuf_get_stringb(m, kex->peer)) != 0 || 2378 (r = sshbuf_get_stringb(m, kex->client_version)) != 0 || 2379 (r = sshbuf_get_stringb(m, kex->server_version)) != 0 || 2380 (r = sshbuf_get_stringb(m, kex->session_id)) != 0 || 2381 (r = sshbuf_get_u32(m, &kex->flags)) != 0) 2382 goto out; 2383 kex->server = 1; 2384 kex->done = 1; 2385 r = 0; 2386 out: 2387 if (r != 0 || kexp == NULL) { 2388 kex_free(kex); 2389 if (kexp != NULL) 2390 *kexp = NULL; 2391 } else { 2392 kex_free(*kexp); 2393 *kexp = kex; 2394 } 2395 return r; 2396 } 2397 2398 /* 2399 * Restore packet state from content of blob 'm' (de-serialization). 2400 * Note that 'm' will be partially consumed on parsing or any other errors. 2401 */ 2402 int 2403 ssh_packet_set_state(struct ssh *ssh, struct sshbuf *m) 2404 { 2405 struct session_state *state = ssh->state; 2406 const u_char *input, *output; 2407 size_t ilen, olen; 2408 int r; 2409 2410 if ((r = kex_from_blob(m, &ssh->kex)) != 0 || 2411 (r = newkeys_from_blob(m, ssh, MODE_OUT)) != 0 || 2412 (r = newkeys_from_blob(m, ssh, MODE_IN)) != 0 || 2413 (r = sshbuf_get_u64(m, &state->rekey_limit)) != 0 || 2414 (r = sshbuf_get_u32(m, &state->rekey_interval)) != 0 || 2415 (r = sshbuf_get_u32(m, &state->p_send.seqnr)) != 0 || 2416 (r = sshbuf_get_u64(m, &state->p_send.blocks)) != 0 || 2417 (r = sshbuf_get_u32(m, &state->p_send.packets)) != 0 || 2418 (r = sshbuf_get_u64(m, &state->p_send.bytes)) != 0 || 2419 (r = sshbuf_get_u32(m, &state->p_read.seqnr)) != 0 || 2420 (r = sshbuf_get_u64(m, &state->p_read.blocks)) != 0 || 2421 (r = sshbuf_get_u32(m, &state->p_read.packets)) != 0 || 2422 (r = sshbuf_get_u64(m, &state->p_read.bytes)) != 0) 2423 return r; 2424 /* 2425 * We set the time here so that in post-auth privsep child we 2426 * count from the completion of the authentication. 2427 */ 2428 state->rekey_time = monotime(); 2429 /* XXX ssh_set_newkeys overrides p_read.packets? XXX */ 2430 if ((r = ssh_set_newkeys(ssh, MODE_IN)) != 0 || 2431 (r = ssh_set_newkeys(ssh, MODE_OUT)) != 0) 2432 return r; 2433 2434 if ((r = ssh_packet_set_postauth(ssh)) != 0) 2435 return r; 2436 2437 sshbuf_reset(state->input); 2438 sshbuf_reset(state->output); 2439 if ((r = sshbuf_get_string_direct(m, &input, &ilen)) != 0 || 2440 (r = sshbuf_get_string_direct(m, &output, &olen)) != 0 || 2441 (r = sshbuf_put(state->input, input, ilen)) != 0 || 2442 (r = sshbuf_put(state->output, output, olen)) != 0) 2443 return r; 2444 2445 if (sshbuf_len(m)) 2446 return SSH_ERR_INVALID_FORMAT; 2447 debug3_f("done"); 2448 return 0; 2449 } 2450 2451 /* NEW API */ 2452 2453 /* put data to the outgoing packet */ 2454 2455 int 2456 sshpkt_put(struct ssh *ssh, const void *v, size_t len) 2457 { 2458 return sshbuf_put(ssh->state->outgoing_packet, v, len); 2459 } 2460 2461 int 2462 sshpkt_putb(struct ssh *ssh, const struct sshbuf *b) 2463 { 2464 return sshbuf_putb(ssh->state->outgoing_packet, b); 2465 } 2466 2467 int 2468 sshpkt_put_u8(struct ssh *ssh, u_char val) 2469 { 2470 return sshbuf_put_u8(ssh->state->outgoing_packet, val); 2471 } 2472 2473 int 2474 sshpkt_put_u32(struct ssh *ssh, u_int32_t val) 2475 { 2476 return sshbuf_put_u32(ssh->state->outgoing_packet, val); 2477 } 2478 2479 int 2480 sshpkt_put_u64(struct ssh *ssh, u_int64_t val) 2481 { 2482 return sshbuf_put_u64(ssh->state->outgoing_packet, val); 2483 } 2484 2485 int 2486 sshpkt_put_string(struct ssh *ssh, const void *v, size_t len) 2487 { 2488 return sshbuf_put_string(ssh->state->outgoing_packet, v, len); 2489 } 2490 2491 int 2492 sshpkt_put_cstring(struct ssh *ssh, const void *v) 2493 { 2494 return sshbuf_put_cstring(ssh->state->outgoing_packet, v); 2495 } 2496 2497 int 2498 sshpkt_put_stringb(struct ssh *ssh, const struct sshbuf *v) 2499 { 2500 return sshbuf_put_stringb(ssh->state->outgoing_packet, v); 2501 } 2502 2503 int 2504 sshpkt_getb_froms(struct ssh *ssh, struct sshbuf **valp) 2505 { 2506 return sshbuf_froms(ssh->state->incoming_packet, valp); 2507 } 2508 2509 #ifdef WITH_OPENSSL 2510 #ifdef OPENSSL_HAS_ECC 2511 int 2512 sshpkt_put_ec(struct ssh *ssh, const EC_POINT *v, const EC_GROUP *g) 2513 { 2514 return sshbuf_put_ec(ssh->state->outgoing_packet, v, g); 2515 } 2516 #endif /* OPENSSL_HAS_ECC */ 2517 2518 2519 int 2520 sshpkt_put_bignum2(struct ssh *ssh, const BIGNUM *v) 2521 { 2522 return sshbuf_put_bignum2(ssh->state->outgoing_packet, v); 2523 } 2524 #endif /* WITH_OPENSSL */ 2525 2526 /* fetch data from the incoming packet */ 2527 2528 int 2529 sshpkt_get(struct ssh *ssh, void *valp, size_t len) 2530 { 2531 return sshbuf_get(ssh->state->incoming_packet, valp, len); 2532 } 2533 2534 int 2535 sshpkt_get_u8(struct ssh *ssh, u_char *valp) 2536 { 2537 return sshbuf_get_u8(ssh->state->incoming_packet, valp); 2538 } 2539 2540 int 2541 sshpkt_get_u32(struct ssh *ssh, u_int32_t *valp) 2542 { 2543 return sshbuf_get_u32(ssh->state->incoming_packet, valp); 2544 } 2545 2546 int 2547 sshpkt_get_u64(struct ssh *ssh, u_int64_t *valp) 2548 { 2549 return sshbuf_get_u64(ssh->state->incoming_packet, valp); 2550 } 2551 2552 int 2553 sshpkt_get_string(struct ssh *ssh, u_char **valp, size_t *lenp) 2554 { 2555 return sshbuf_get_string(ssh->state->incoming_packet, valp, lenp); 2556 } 2557 2558 int 2559 sshpkt_get_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp) 2560 { 2561 return sshbuf_get_string_direct(ssh->state->incoming_packet, valp, lenp); 2562 } 2563 2564 int 2565 sshpkt_peek_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp) 2566 { 2567 return sshbuf_peek_string_direct(ssh->state->incoming_packet, valp, lenp); 2568 } 2569 2570 int 2571 sshpkt_get_cstring(struct ssh *ssh, char **valp, size_t *lenp) 2572 { 2573 return sshbuf_get_cstring(ssh->state->incoming_packet, valp, lenp); 2574 } 2575 2576 #ifdef WITH_OPENSSL 2577 #ifdef OPENSSL_HAS_ECC 2578 int 2579 sshpkt_get_ec(struct ssh *ssh, EC_POINT *v, const EC_GROUP *g) 2580 { 2581 return sshbuf_get_ec(ssh->state->incoming_packet, v, g); 2582 } 2583 #endif /* OPENSSL_HAS_ECC */ 2584 2585 int 2586 sshpkt_get_bignum2(struct ssh *ssh, BIGNUM **valp) 2587 { 2588 return sshbuf_get_bignum2(ssh->state->incoming_packet, valp); 2589 } 2590 #endif /* WITH_OPENSSL */ 2591 2592 int 2593 sshpkt_get_end(struct ssh *ssh) 2594 { 2595 if (sshbuf_len(ssh->state->incoming_packet) > 0) 2596 return SSH_ERR_UNEXPECTED_TRAILING_DATA; 2597 return 0; 2598 } 2599 2600 const u_char * 2601 sshpkt_ptr(struct ssh *ssh, size_t *lenp) 2602 { 2603 if (lenp != NULL) 2604 *lenp = sshbuf_len(ssh->state->incoming_packet); 2605 return sshbuf_ptr(ssh->state->incoming_packet); 2606 } 2607 2608 /* start a new packet */ 2609 2610 int 2611 sshpkt_start(struct ssh *ssh, u_char type) 2612 { 2613 u_char buf[6]; /* u32 packet length, u8 pad len, u8 type */ 2614 2615 DBG(debug("packet_start[%d]", type)); 2616 memset(buf, 0, sizeof(buf)); 2617 buf[sizeof(buf) - 1] = type; 2618 sshbuf_reset(ssh->state->outgoing_packet); 2619 return sshbuf_put(ssh->state->outgoing_packet, buf, sizeof(buf)); 2620 } 2621 2622 static int 2623 ssh_packet_send_mux(struct ssh *ssh) 2624 { 2625 struct session_state *state = ssh->state; 2626 u_char type, *cp; 2627 size_t len; 2628 int r; 2629 2630 if (ssh->kex) 2631 return SSH_ERR_INTERNAL_ERROR; 2632 len = sshbuf_len(state->outgoing_packet); 2633 if (len < 6) 2634 return SSH_ERR_INTERNAL_ERROR; 2635 cp = sshbuf_mutable_ptr(state->outgoing_packet); 2636 type = cp[5]; 2637 if (ssh_packet_log_type(type)) 2638 debug3_f("type %u", type); 2639 /* drop everything, but the connection protocol */ 2640 if (type >= SSH2_MSG_CONNECTION_MIN && 2641 type <= SSH2_MSG_CONNECTION_MAX) { 2642 POKE_U32(cp, len - 4); 2643 if ((r = sshbuf_putb(state->output, 2644 state->outgoing_packet)) != 0) 2645 return r; 2646 /* sshbuf_dump(state->output, stderr); */ 2647 } 2648 sshbuf_reset(state->outgoing_packet); 2649 return 0; 2650 } 2651 2652 /* 2653 * 9.2. Ignored Data Message 2654 * 2655 * byte SSH_MSG_IGNORE 2656 * string data 2657 * 2658 * All implementations MUST understand (and ignore) this message at any 2659 * time (after receiving the protocol version). No implementation is 2660 * required to send them. This message can be used as an additional 2661 * protection measure against advanced traffic analysis techniques. 2662 */ 2663 int 2664 sshpkt_msg_ignore(struct ssh *ssh, u_int nbytes) 2665 { 2666 u_int32_t rnd = 0; 2667 int r; 2668 u_int i; 2669 2670 if ((r = sshpkt_start(ssh, SSH2_MSG_IGNORE)) != 0 || 2671 (r = sshpkt_put_u32(ssh, nbytes)) != 0) 2672 return r; 2673 for (i = 0; i < nbytes; i++) { 2674 if (i % 4 == 0) 2675 rnd = arc4random(); 2676 if ((r = sshpkt_put_u8(ssh, (u_char)rnd & 0xff)) != 0) 2677 return r; 2678 rnd >>= 8; 2679 } 2680 return 0; 2681 } 2682 2683 /* send it */ 2684 2685 int 2686 sshpkt_send(struct ssh *ssh) 2687 { 2688 if (ssh->state && ssh->state->mux) 2689 return ssh_packet_send_mux(ssh); 2690 return ssh_packet_send2(ssh); 2691 } 2692 2693 int 2694 sshpkt_disconnect(struct ssh *ssh, const char *fmt,...) 2695 { 2696 char buf[1024]; 2697 va_list args; 2698 int r; 2699 2700 va_start(args, fmt); 2701 vsnprintf(buf, sizeof(buf), fmt, args); 2702 va_end(args); 2703 2704 if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 || 2705 (r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_PROTOCOL_ERROR)) != 0 || 2706 (r = sshpkt_put_cstring(ssh, buf)) != 0 || 2707 (r = sshpkt_put_cstring(ssh, "")) != 0 || 2708 (r = sshpkt_send(ssh)) != 0) 2709 return r; 2710 return 0; 2711 } 2712 2713 /* roundup current message to pad bytes */ 2714 int 2715 sshpkt_add_padding(struct ssh *ssh, u_char pad) 2716 { 2717 ssh->state->extra_pad = pad; 2718 return 0; 2719 } 2720