1 /* $OpenBSD: packet.c,v 1.291 2020/03/06 18:20:44 markus 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 || ssh->kex->done == 0; 286 } 287 288 /* 289 * Sets the descriptors used for communication. 290 */ 291 struct ssh * 292 ssh_packet_set_connection(struct ssh *ssh, int fd_in, int fd_out) 293 { 294 struct session_state *state; 295 const struct sshcipher *none = cipher_by_name("none"); 296 int r; 297 298 if (none == NULL) { 299 error("%s: cannot load cipher 'none'", __func__); 300 return NULL; 301 } 302 if (ssh == NULL) 303 ssh = ssh_alloc_session_state(); 304 if (ssh == NULL) { 305 error("%s: could not allocate state", __func__); 306 return NULL; 307 } 308 state = ssh->state; 309 state->connection_in = fd_in; 310 state->connection_out = fd_out; 311 if ((r = cipher_init(&state->send_context, none, 312 (const u_char *)"", 0, NULL, 0, CIPHER_ENCRYPT)) != 0 || 313 (r = cipher_init(&state->receive_context, none, 314 (const u_char *)"", 0, NULL, 0, CIPHER_DECRYPT)) != 0) { 315 error("%s: cipher_init failed: %s", __func__, ssh_err(r)); 316 free(ssh); /* XXX need ssh_free_session_state? */ 317 return NULL; 318 } 319 state->newkeys[MODE_IN] = state->newkeys[MODE_OUT] = NULL; 320 /* 321 * Cache the IP address of the remote connection for use in error 322 * messages that might be generated after the connection has closed. 323 */ 324 (void)ssh_remote_ipaddr(ssh); 325 return ssh; 326 } 327 328 void 329 ssh_packet_set_timeout(struct ssh *ssh, int timeout, int count) 330 { 331 struct session_state *state = ssh->state; 332 333 if (timeout <= 0 || count <= 0) { 334 state->packet_timeout_ms = -1; 335 return; 336 } 337 if ((INT_MAX / 1000) / count < timeout) 338 state->packet_timeout_ms = INT_MAX; 339 else 340 state->packet_timeout_ms = timeout * count * 1000; 341 } 342 343 void 344 ssh_packet_set_mux(struct ssh *ssh) 345 { 346 ssh->state->mux = 1; 347 ssh->state->rekeying = 0; 348 } 349 350 int 351 ssh_packet_get_mux(struct ssh *ssh) 352 { 353 return ssh->state->mux; 354 } 355 356 int 357 ssh_packet_set_log_preamble(struct ssh *ssh, const char *fmt, ...) 358 { 359 va_list args; 360 int r; 361 362 free(ssh->log_preamble); 363 if (fmt == NULL) 364 ssh->log_preamble = NULL; 365 else { 366 va_start(args, fmt); 367 r = vasprintf(&ssh->log_preamble, fmt, args); 368 va_end(args); 369 if (r < 0 || ssh->log_preamble == NULL) 370 return SSH_ERR_ALLOC_FAIL; 371 } 372 return 0; 373 } 374 375 int 376 ssh_packet_stop_discard(struct ssh *ssh) 377 { 378 struct session_state *state = ssh->state; 379 int r; 380 381 if (state->packet_discard_mac) { 382 char buf[1024]; 383 size_t dlen = PACKET_MAX_SIZE; 384 385 if (dlen > state->packet_discard_mac_already) 386 dlen -= state->packet_discard_mac_already; 387 memset(buf, 'a', sizeof(buf)); 388 while (sshbuf_len(state->incoming_packet) < dlen) 389 if ((r = sshbuf_put(state->incoming_packet, buf, 390 sizeof(buf))) != 0) 391 return r; 392 (void) mac_compute(state->packet_discard_mac, 393 state->p_read.seqnr, 394 sshbuf_ptr(state->incoming_packet), dlen, 395 NULL, 0); 396 } 397 logit("Finished discarding for %.200s port %d", 398 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 399 return SSH_ERR_MAC_INVALID; 400 } 401 402 static int 403 ssh_packet_start_discard(struct ssh *ssh, struct sshenc *enc, 404 struct sshmac *mac, size_t mac_already, u_int discard) 405 { 406 struct session_state *state = ssh->state; 407 int r; 408 409 if (enc == NULL || !cipher_is_cbc(enc->cipher) || (mac && mac->etm)) { 410 if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0) 411 return r; 412 return SSH_ERR_MAC_INVALID; 413 } 414 /* 415 * Record number of bytes over which the mac has already 416 * been computed in order to minimize timing attacks. 417 */ 418 if (mac && mac->enabled) { 419 state->packet_discard_mac = mac; 420 state->packet_discard_mac_already = mac_already; 421 } 422 if (sshbuf_len(state->input) >= discard) 423 return ssh_packet_stop_discard(ssh); 424 state->packet_discard = discard - sshbuf_len(state->input); 425 return 0; 426 } 427 428 /* Returns 1 if remote host is connected via socket, 0 if not. */ 429 430 int 431 ssh_packet_connection_is_on_socket(struct ssh *ssh) 432 { 433 struct session_state *state; 434 struct sockaddr_storage from, to; 435 socklen_t fromlen, tolen; 436 437 if (ssh == NULL || ssh->state == NULL) 438 return 0; 439 440 state = ssh->state; 441 if (state->connection_in == -1 || state->connection_out == -1) 442 return 0; 443 /* filedescriptors in and out are the same, so it's a socket */ 444 if (state->connection_in == state->connection_out) 445 return 1; 446 fromlen = sizeof(from); 447 memset(&from, 0, sizeof(from)); 448 if (getpeername(state->connection_in, (struct sockaddr *)&from, 449 &fromlen) == -1) 450 return 0; 451 tolen = sizeof(to); 452 memset(&to, 0, sizeof(to)); 453 if (getpeername(state->connection_out, (struct sockaddr *)&to, 454 &tolen) == -1) 455 return 0; 456 if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0) 457 return 0; 458 if (from.ss_family != AF_INET && from.ss_family != AF_INET6) 459 return 0; 460 return 1; 461 } 462 463 void 464 ssh_packet_get_bytes(struct ssh *ssh, u_int64_t *ibytes, u_int64_t *obytes) 465 { 466 if (ibytes) 467 *ibytes = ssh->state->p_read.bytes; 468 if (obytes) 469 *obytes = ssh->state->p_send.bytes; 470 } 471 472 int 473 ssh_packet_connection_af(struct ssh *ssh) 474 { 475 struct sockaddr_storage to; 476 socklen_t tolen = sizeof(to); 477 478 memset(&to, 0, sizeof(to)); 479 if (getsockname(ssh->state->connection_out, (struct sockaddr *)&to, 480 &tolen) == -1) 481 return 0; 482 #ifdef IPV4_IN_IPV6 483 if (to.ss_family == AF_INET6 && 484 IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&to)->sin6_addr)) 485 return AF_INET; 486 #endif 487 return to.ss_family; 488 } 489 490 /* Sets the connection into non-blocking mode. */ 491 492 void 493 ssh_packet_set_nonblocking(struct ssh *ssh) 494 { 495 /* Set the socket into non-blocking mode. */ 496 set_nonblock(ssh->state->connection_in); 497 498 if (ssh->state->connection_out != ssh->state->connection_in) 499 set_nonblock(ssh->state->connection_out); 500 } 501 502 /* Returns the socket used for reading. */ 503 504 int 505 ssh_packet_get_connection_in(struct ssh *ssh) 506 { 507 return ssh->state->connection_in; 508 } 509 510 /* Returns the descriptor used for writing. */ 511 512 int 513 ssh_packet_get_connection_out(struct ssh *ssh) 514 { 515 return ssh->state->connection_out; 516 } 517 518 /* 519 * Returns the IP-address of the remote host as a string. The returned 520 * string must not be freed. 521 */ 522 523 const char * 524 ssh_remote_ipaddr(struct ssh *ssh) 525 { 526 int sock; 527 528 /* Check whether we have cached the ipaddr. */ 529 if (ssh->remote_ipaddr == NULL) { 530 if (ssh_packet_connection_is_on_socket(ssh)) { 531 sock = ssh->state->connection_in; 532 ssh->remote_ipaddr = get_peer_ipaddr(sock); 533 ssh->remote_port = get_peer_port(sock); 534 ssh->local_ipaddr = get_local_ipaddr(sock); 535 ssh->local_port = get_local_port(sock); 536 } else { 537 ssh->remote_ipaddr = xstrdup("UNKNOWN"); 538 ssh->remote_port = 65535; 539 ssh->local_ipaddr = xstrdup("UNKNOWN"); 540 ssh->local_port = 65535; 541 } 542 } 543 return ssh->remote_ipaddr; 544 } 545 546 /* Returns the port number of the remote host. */ 547 548 int 549 ssh_remote_port(struct ssh *ssh) 550 { 551 (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */ 552 return ssh->remote_port; 553 } 554 555 /* 556 * Returns the IP-address of the local host as a string. The returned 557 * string must not be freed. 558 */ 559 560 const char * 561 ssh_local_ipaddr(struct ssh *ssh) 562 { 563 (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */ 564 return ssh->local_ipaddr; 565 } 566 567 /* Returns the port number of the local host. */ 568 569 int 570 ssh_local_port(struct ssh *ssh) 571 { 572 (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */ 573 return ssh->local_port; 574 } 575 576 /* Returns the routing domain of the input socket, or NULL if unavailable */ 577 const char * 578 ssh_packet_rdomain_in(struct ssh *ssh) 579 { 580 if (ssh->rdomain_in != NULL) 581 return ssh->rdomain_in; 582 if (!ssh_packet_connection_is_on_socket(ssh)) 583 return NULL; 584 ssh->rdomain_in = get_rdomain(ssh->state->connection_in); 585 return ssh->rdomain_in; 586 } 587 588 /* Closes the connection and clears and frees internal data structures. */ 589 590 static void 591 ssh_packet_close_internal(struct ssh *ssh, int do_close) 592 { 593 struct session_state *state = ssh->state; 594 u_int mode; 595 596 if (!state->initialized) 597 return; 598 state->initialized = 0; 599 if (do_close) { 600 if (state->connection_in == state->connection_out) { 601 close(state->connection_out); 602 } else { 603 close(state->connection_in); 604 close(state->connection_out); 605 } 606 } 607 sshbuf_free(state->input); 608 sshbuf_free(state->output); 609 sshbuf_free(state->outgoing_packet); 610 sshbuf_free(state->incoming_packet); 611 for (mode = 0; mode < MODE_MAX; mode++) { 612 kex_free_newkeys(state->newkeys[mode]); /* current keys */ 613 state->newkeys[mode] = NULL; 614 ssh_clear_newkeys(ssh, mode); /* next keys */ 615 } 616 #ifdef WITH_ZLIB 617 /* compression state is in shared mem, so we can only release it once */ 618 if (do_close && state->compression_buffer) { 619 sshbuf_free(state->compression_buffer); 620 if (state->compression_out_started) { 621 z_streamp stream = &state->compression_out_stream; 622 debug("compress outgoing: " 623 "raw data %llu, compressed %llu, factor %.2f", 624 (unsigned long long)stream->total_in, 625 (unsigned long long)stream->total_out, 626 stream->total_in == 0 ? 0.0 : 627 (double) stream->total_out / stream->total_in); 628 if (state->compression_out_failures == 0) 629 deflateEnd(stream); 630 } 631 if (state->compression_in_started) { 632 z_streamp stream = &state->compression_in_stream; 633 debug("compress incoming: " 634 "raw data %llu, compressed %llu, factor %.2f", 635 (unsigned long long)stream->total_out, 636 (unsigned long long)stream->total_in, 637 stream->total_out == 0 ? 0.0 : 638 (double) stream->total_in / stream->total_out); 639 if (state->compression_in_failures == 0) 640 inflateEnd(stream); 641 } 642 } 643 #endif /* WITH_ZLIB */ 644 cipher_free(state->send_context); 645 cipher_free(state->receive_context); 646 state->send_context = state->receive_context = NULL; 647 if (do_close) { 648 free(ssh->local_ipaddr); 649 ssh->local_ipaddr = NULL; 650 free(ssh->remote_ipaddr); 651 ssh->remote_ipaddr = NULL; 652 free(ssh->state); 653 ssh->state = NULL; 654 } 655 } 656 657 void 658 ssh_packet_close(struct ssh *ssh) 659 { 660 ssh_packet_close_internal(ssh, 1); 661 } 662 663 void 664 ssh_packet_clear_keys(struct ssh *ssh) 665 { 666 ssh_packet_close_internal(ssh, 0); 667 } 668 669 /* Sets remote side protocol flags. */ 670 671 void 672 ssh_packet_set_protocol_flags(struct ssh *ssh, u_int protocol_flags) 673 { 674 ssh->state->remote_protocol_flags = protocol_flags; 675 } 676 677 /* Returns the remote protocol flags set earlier by the above function. */ 678 679 u_int 680 ssh_packet_get_protocol_flags(struct ssh *ssh) 681 { 682 return ssh->state->remote_protocol_flags; 683 } 684 685 /* 686 * Starts packet compression from the next packet on in both directions. 687 * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip. 688 */ 689 690 static int 691 ssh_packet_init_compression(struct ssh *ssh) 692 { 693 if (!ssh->state->compression_buffer && 694 ((ssh->state->compression_buffer = sshbuf_new()) == NULL)) 695 return SSH_ERR_ALLOC_FAIL; 696 return 0; 697 } 698 699 #ifdef WITH_ZLIB 700 static int 701 start_compression_out(struct ssh *ssh, int level) 702 { 703 if (level < 1 || level > 9) 704 return SSH_ERR_INVALID_ARGUMENT; 705 debug("Enabling compression at level %d.", level); 706 if (ssh->state->compression_out_started == 1) 707 deflateEnd(&ssh->state->compression_out_stream); 708 switch (deflateInit(&ssh->state->compression_out_stream, level)) { 709 case Z_OK: 710 ssh->state->compression_out_started = 1; 711 break; 712 case Z_MEM_ERROR: 713 return SSH_ERR_ALLOC_FAIL; 714 default: 715 return SSH_ERR_INTERNAL_ERROR; 716 } 717 return 0; 718 } 719 720 static int 721 start_compression_in(struct ssh *ssh) 722 { 723 if (ssh->state->compression_in_started == 1) 724 inflateEnd(&ssh->state->compression_in_stream); 725 switch (inflateInit(&ssh->state->compression_in_stream)) { 726 case Z_OK: 727 ssh->state->compression_in_started = 1; 728 break; 729 case Z_MEM_ERROR: 730 return SSH_ERR_ALLOC_FAIL; 731 default: 732 return SSH_ERR_INTERNAL_ERROR; 733 } 734 return 0; 735 } 736 737 /* XXX remove need for separate compression buffer */ 738 static int 739 compress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out) 740 { 741 u_char buf[4096]; 742 int r, status; 743 744 if (ssh->state->compression_out_started != 1) 745 return SSH_ERR_INTERNAL_ERROR; 746 747 /* This case is not handled below. */ 748 if (sshbuf_len(in) == 0) 749 return 0; 750 751 /* Input is the contents of the input buffer. */ 752 if ((ssh->state->compression_out_stream.next_in = 753 sshbuf_mutable_ptr(in)) == NULL) 754 return SSH_ERR_INTERNAL_ERROR; 755 ssh->state->compression_out_stream.avail_in = sshbuf_len(in); 756 757 /* Loop compressing until deflate() returns with avail_out != 0. */ 758 do { 759 /* Set up fixed-size output buffer. */ 760 ssh->state->compression_out_stream.next_out = buf; 761 ssh->state->compression_out_stream.avail_out = sizeof(buf); 762 763 /* Compress as much data into the buffer as possible. */ 764 status = deflate(&ssh->state->compression_out_stream, 765 Z_PARTIAL_FLUSH); 766 switch (status) { 767 case Z_MEM_ERROR: 768 return SSH_ERR_ALLOC_FAIL; 769 case Z_OK: 770 /* Append compressed data to output_buffer. */ 771 if ((r = sshbuf_put(out, buf, sizeof(buf) - 772 ssh->state->compression_out_stream.avail_out)) != 0) 773 return r; 774 break; 775 case Z_STREAM_ERROR: 776 default: 777 ssh->state->compression_out_failures++; 778 return SSH_ERR_INVALID_FORMAT; 779 } 780 } while (ssh->state->compression_out_stream.avail_out == 0); 781 return 0; 782 } 783 784 static int 785 uncompress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out) 786 { 787 u_char buf[4096]; 788 int r, status; 789 790 if (ssh->state->compression_in_started != 1) 791 return SSH_ERR_INTERNAL_ERROR; 792 793 if ((ssh->state->compression_in_stream.next_in = 794 sshbuf_mutable_ptr(in)) == NULL) 795 return SSH_ERR_INTERNAL_ERROR; 796 ssh->state->compression_in_stream.avail_in = sshbuf_len(in); 797 798 for (;;) { 799 /* Set up fixed-size output buffer. */ 800 ssh->state->compression_in_stream.next_out = buf; 801 ssh->state->compression_in_stream.avail_out = sizeof(buf); 802 803 status = inflate(&ssh->state->compression_in_stream, 804 Z_PARTIAL_FLUSH); 805 switch (status) { 806 case Z_OK: 807 if ((r = sshbuf_put(out, buf, sizeof(buf) - 808 ssh->state->compression_in_stream.avail_out)) != 0) 809 return r; 810 break; 811 case Z_BUF_ERROR: 812 /* 813 * Comments in zlib.h say that we should keep calling 814 * inflate() until we get an error. This appears to 815 * be the error that we get. 816 */ 817 return 0; 818 case Z_DATA_ERROR: 819 return SSH_ERR_INVALID_FORMAT; 820 case Z_MEM_ERROR: 821 return SSH_ERR_ALLOC_FAIL; 822 case Z_STREAM_ERROR: 823 default: 824 ssh->state->compression_in_failures++; 825 return SSH_ERR_INTERNAL_ERROR; 826 } 827 } 828 /* NOTREACHED */ 829 } 830 831 #else /* WITH_ZLIB */ 832 833 static int 834 start_compression_out(struct ssh *ssh, int level) 835 { 836 return SSH_ERR_INTERNAL_ERROR; 837 } 838 839 static int 840 start_compression_in(struct ssh *ssh) 841 { 842 return SSH_ERR_INTERNAL_ERROR; 843 } 844 845 static int 846 compress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out) 847 { 848 return SSH_ERR_INTERNAL_ERROR; 849 } 850 851 static int 852 uncompress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out) 853 { 854 return SSH_ERR_INTERNAL_ERROR; 855 } 856 #endif /* WITH_ZLIB */ 857 858 void 859 ssh_clear_newkeys(struct ssh *ssh, int mode) 860 { 861 if (ssh->kex && ssh->kex->newkeys[mode]) { 862 kex_free_newkeys(ssh->kex->newkeys[mode]); 863 ssh->kex->newkeys[mode] = NULL; 864 } 865 } 866 867 int 868 ssh_set_newkeys(struct ssh *ssh, int mode) 869 { 870 struct session_state *state = ssh->state; 871 struct sshenc *enc; 872 struct sshmac *mac; 873 struct sshcomp *comp; 874 struct sshcipher_ctx **ccp; 875 struct packet_state *ps; 876 u_int64_t *max_blocks; 877 const char *wmsg; 878 int r, crypt_type; 879 const char *dir = mode == MODE_OUT ? "out" : "in"; 880 881 debug2("set_newkeys: mode %d", mode); 882 883 if (mode == MODE_OUT) { 884 ccp = &state->send_context; 885 crypt_type = CIPHER_ENCRYPT; 886 ps = &state->p_send; 887 max_blocks = &state->max_blocks_out; 888 } else { 889 ccp = &state->receive_context; 890 crypt_type = CIPHER_DECRYPT; 891 ps = &state->p_read; 892 max_blocks = &state->max_blocks_in; 893 } 894 if (state->newkeys[mode] != NULL) { 895 debug("%s: rekeying %s, input %llu bytes %llu blocks, " 896 "output %llu bytes %llu blocks", __func__, dir, 897 (unsigned long long)state->p_read.bytes, 898 (unsigned long long)state->p_read.blocks, 899 (unsigned long long)state->p_send.bytes, 900 (unsigned long long)state->p_send.blocks); 901 kex_free_newkeys(state->newkeys[mode]); 902 state->newkeys[mode] = NULL; 903 } 904 /* note that both bytes and the seqnr are not reset */ 905 ps->packets = ps->blocks = 0; 906 /* move newkeys from kex to state */ 907 if ((state->newkeys[mode] = ssh->kex->newkeys[mode]) == NULL) 908 return SSH_ERR_INTERNAL_ERROR; 909 ssh->kex->newkeys[mode] = NULL; 910 enc = &state->newkeys[mode]->enc; 911 mac = &state->newkeys[mode]->mac; 912 comp = &state->newkeys[mode]->comp; 913 if (cipher_authlen(enc->cipher) == 0) { 914 if ((r = mac_init(mac)) != 0) 915 return r; 916 } 917 mac->enabled = 1; 918 DBG(debug("%s: cipher_init_context: %s", __func__, dir)); 919 cipher_free(*ccp); 920 *ccp = NULL; 921 if ((r = cipher_init(ccp, enc->cipher, enc->key, enc->key_len, 922 enc->iv, enc->iv_len, crypt_type)) != 0) 923 return r; 924 if (!state->cipher_warning_done && 925 (wmsg = cipher_warning_message(*ccp)) != NULL) { 926 error("Warning: %s", wmsg); 927 state->cipher_warning_done = 1; 928 } 929 /* Deleting the keys does not gain extra security */ 930 /* explicit_bzero(enc->iv, enc->block_size); 931 explicit_bzero(enc->key, enc->key_len); 932 explicit_bzero(mac->key, mac->key_len); */ 933 if ((comp->type == COMP_ZLIB || 934 (comp->type == COMP_DELAYED && 935 state->after_authentication)) && comp->enabled == 0) { 936 if ((r = ssh_packet_init_compression(ssh)) < 0) 937 return r; 938 if (mode == MODE_OUT) { 939 if ((r = start_compression_out(ssh, 6)) != 0) 940 return r; 941 } else { 942 if ((r = start_compression_in(ssh)) != 0) 943 return r; 944 } 945 comp->enabled = 1; 946 } 947 /* 948 * The 2^(blocksize*2) limit is too expensive for 3DES, 949 * so enforce a 1GB limit for small blocksizes. 950 * See RFC4344 section 3.2. 951 */ 952 if (enc->block_size >= 16) 953 *max_blocks = (u_int64_t)1 << (enc->block_size*2); 954 else 955 *max_blocks = ((u_int64_t)1 << 30) / enc->block_size; 956 if (state->rekey_limit) 957 *max_blocks = MINIMUM(*max_blocks, 958 state->rekey_limit / enc->block_size); 959 debug("rekey %s after %llu blocks", dir, 960 (unsigned long long)*max_blocks); 961 return 0; 962 } 963 964 #define MAX_PACKETS (1U<<31) 965 static int 966 ssh_packet_need_rekeying(struct ssh *ssh, u_int outbound_packet_len) 967 { 968 struct session_state *state = ssh->state; 969 u_int32_t out_blocks; 970 971 /* XXX client can't cope with rekeying pre-auth */ 972 if (!state->after_authentication) 973 return 0; 974 975 /* Haven't keyed yet or KEX in progress. */ 976 if (ssh_packet_is_rekeying(ssh)) 977 return 0; 978 979 /* Peer can't rekey */ 980 if (ssh->compat & SSH_BUG_NOREKEY) 981 return 0; 982 983 /* 984 * Permit one packet in or out per rekey - this allows us to 985 * make progress when rekey limits are very small. 986 */ 987 if (state->p_send.packets == 0 && state->p_read.packets == 0) 988 return 0; 989 990 /* Time-based rekeying */ 991 if (state->rekey_interval != 0 && 992 (int64_t)state->rekey_time + state->rekey_interval <= monotime()) 993 return 1; 994 995 /* 996 * Always rekey when MAX_PACKETS sent in either direction 997 * As per RFC4344 section 3.1 we do this after 2^31 packets. 998 */ 999 if (state->p_send.packets > MAX_PACKETS || 1000 state->p_read.packets > MAX_PACKETS) 1001 return 1; 1002 1003 /* Rekey after (cipher-specific) maximum blocks */ 1004 out_blocks = ROUNDUP(outbound_packet_len, 1005 state->newkeys[MODE_OUT]->enc.block_size); 1006 return (state->max_blocks_out && 1007 (state->p_send.blocks + out_blocks > state->max_blocks_out)) || 1008 (state->max_blocks_in && 1009 (state->p_read.blocks > state->max_blocks_in)); 1010 } 1011 1012 /* 1013 * Delayed compression for SSH2 is enabled after authentication: 1014 * This happens on the server side after a SSH2_MSG_USERAUTH_SUCCESS is sent, 1015 * and on the client side after a SSH2_MSG_USERAUTH_SUCCESS is received. 1016 */ 1017 static int 1018 ssh_packet_enable_delayed_compress(struct ssh *ssh) 1019 { 1020 struct session_state *state = ssh->state; 1021 struct sshcomp *comp = NULL; 1022 int r, mode; 1023 1024 /* 1025 * Remember that we are past the authentication step, so rekeying 1026 * with COMP_DELAYED will turn on compression immediately. 1027 */ 1028 state->after_authentication = 1; 1029 for (mode = 0; mode < MODE_MAX; mode++) { 1030 /* protocol error: USERAUTH_SUCCESS received before NEWKEYS */ 1031 if (state->newkeys[mode] == NULL) 1032 continue; 1033 comp = &state->newkeys[mode]->comp; 1034 if (comp && !comp->enabled && comp->type == COMP_DELAYED) { 1035 if ((r = ssh_packet_init_compression(ssh)) != 0) 1036 return r; 1037 if (mode == MODE_OUT) { 1038 if ((r = start_compression_out(ssh, 6)) != 0) 1039 return r; 1040 } else { 1041 if ((r = start_compression_in(ssh)) != 0) 1042 return r; 1043 } 1044 comp->enabled = 1; 1045 } 1046 } 1047 return 0; 1048 } 1049 1050 /* Used to mute debug logging for noisy packet types */ 1051 int 1052 ssh_packet_log_type(u_char type) 1053 { 1054 switch (type) { 1055 case SSH2_MSG_CHANNEL_DATA: 1056 case SSH2_MSG_CHANNEL_EXTENDED_DATA: 1057 case SSH2_MSG_CHANNEL_WINDOW_ADJUST: 1058 return 0; 1059 default: 1060 return 1; 1061 } 1062 } 1063 1064 /* 1065 * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue) 1066 */ 1067 int 1068 ssh_packet_send2_wrapped(struct ssh *ssh) 1069 { 1070 struct session_state *state = ssh->state; 1071 u_char type, *cp, macbuf[SSH_DIGEST_MAX_LENGTH]; 1072 u_char tmp, padlen, pad = 0; 1073 u_int authlen = 0, aadlen = 0; 1074 u_int len; 1075 struct sshenc *enc = NULL; 1076 struct sshmac *mac = NULL; 1077 struct sshcomp *comp = NULL; 1078 int r, block_size; 1079 1080 if (state->newkeys[MODE_OUT] != NULL) { 1081 enc = &state->newkeys[MODE_OUT]->enc; 1082 mac = &state->newkeys[MODE_OUT]->mac; 1083 comp = &state->newkeys[MODE_OUT]->comp; 1084 /* disable mac for authenticated encryption */ 1085 if ((authlen = cipher_authlen(enc->cipher)) != 0) 1086 mac = NULL; 1087 } 1088 block_size = enc ? enc->block_size : 8; 1089 aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0; 1090 1091 type = (sshbuf_ptr(state->outgoing_packet))[5]; 1092 if (ssh_packet_log_type(type)) 1093 debug3("send packet: type %u", type); 1094 #ifdef PACKET_DEBUG 1095 fprintf(stderr, "plain: "); 1096 sshbuf_dump(state->outgoing_packet, stderr); 1097 #endif 1098 1099 if (comp && comp->enabled) { 1100 len = sshbuf_len(state->outgoing_packet); 1101 /* skip header, compress only payload */ 1102 if ((r = sshbuf_consume(state->outgoing_packet, 5)) != 0) 1103 goto out; 1104 sshbuf_reset(state->compression_buffer); 1105 if ((r = compress_buffer(ssh, state->outgoing_packet, 1106 state->compression_buffer)) != 0) 1107 goto out; 1108 sshbuf_reset(state->outgoing_packet); 1109 if ((r = sshbuf_put(state->outgoing_packet, 1110 "\0\0\0\0\0", 5)) != 0 || 1111 (r = sshbuf_putb(state->outgoing_packet, 1112 state->compression_buffer)) != 0) 1113 goto out; 1114 DBG(debug("compression: raw %d compressed %zd", len, 1115 sshbuf_len(state->outgoing_packet))); 1116 } 1117 1118 /* sizeof (packet_len + pad_len + payload) */ 1119 len = sshbuf_len(state->outgoing_packet); 1120 1121 /* 1122 * calc size of padding, alloc space, get random data, 1123 * minimum padding is 4 bytes 1124 */ 1125 len -= aadlen; /* packet length is not encrypted for EtM modes */ 1126 padlen = block_size - (len % block_size); 1127 if (padlen < 4) 1128 padlen += block_size; 1129 if (state->extra_pad) { 1130 tmp = state->extra_pad; 1131 state->extra_pad = 1132 ROUNDUP(state->extra_pad, block_size); 1133 /* check if roundup overflowed */ 1134 if (state->extra_pad < tmp) 1135 return SSH_ERR_INVALID_ARGUMENT; 1136 tmp = (len + padlen) % state->extra_pad; 1137 /* Check whether pad calculation below will underflow */ 1138 if (tmp > state->extra_pad) 1139 return SSH_ERR_INVALID_ARGUMENT; 1140 pad = state->extra_pad - tmp; 1141 DBG(debug3("%s: adding %d (len %d padlen %d extra_pad %d)", 1142 __func__, pad, len, padlen, state->extra_pad)); 1143 tmp = padlen; 1144 padlen += pad; 1145 /* Check whether padlen calculation overflowed */ 1146 if (padlen < tmp) 1147 return SSH_ERR_INVALID_ARGUMENT; /* overflow */ 1148 state->extra_pad = 0; 1149 } 1150 if ((r = sshbuf_reserve(state->outgoing_packet, padlen, &cp)) != 0) 1151 goto out; 1152 if (enc && !cipher_ctx_is_plaintext(state->send_context)) { 1153 /* random padding */ 1154 arc4random_buf(cp, padlen); 1155 } else { 1156 /* clear padding */ 1157 explicit_bzero(cp, padlen); 1158 } 1159 /* sizeof (packet_len + pad_len + payload + padding) */ 1160 len = sshbuf_len(state->outgoing_packet); 1161 cp = sshbuf_mutable_ptr(state->outgoing_packet); 1162 if (cp == NULL) { 1163 r = SSH_ERR_INTERNAL_ERROR; 1164 goto out; 1165 } 1166 /* packet_length includes payload, padding and padding length field */ 1167 POKE_U32(cp, len - 4); 1168 cp[4] = padlen; 1169 DBG(debug("send: len %d (includes padlen %d, aadlen %d)", 1170 len, padlen, aadlen)); 1171 1172 /* compute MAC over seqnr and packet(length fields, payload, padding) */ 1173 if (mac && mac->enabled && !mac->etm) { 1174 if ((r = mac_compute(mac, state->p_send.seqnr, 1175 sshbuf_ptr(state->outgoing_packet), len, 1176 macbuf, sizeof(macbuf))) != 0) 1177 goto out; 1178 DBG(debug("done calc MAC out #%d", state->p_send.seqnr)); 1179 } 1180 /* encrypt packet and append to output buffer. */ 1181 if ((r = sshbuf_reserve(state->output, 1182 sshbuf_len(state->outgoing_packet) + authlen, &cp)) != 0) 1183 goto out; 1184 if ((r = cipher_crypt(state->send_context, state->p_send.seqnr, cp, 1185 sshbuf_ptr(state->outgoing_packet), 1186 len - aadlen, aadlen, authlen)) != 0) 1187 goto out; 1188 /* append unencrypted MAC */ 1189 if (mac && mac->enabled) { 1190 if (mac->etm) { 1191 /* EtM: compute mac over aadlen + cipher text */ 1192 if ((r = mac_compute(mac, state->p_send.seqnr, 1193 cp, len, macbuf, sizeof(macbuf))) != 0) 1194 goto out; 1195 DBG(debug("done calc MAC(EtM) out #%d", 1196 state->p_send.seqnr)); 1197 } 1198 if ((r = sshbuf_put(state->output, macbuf, mac->mac_len)) != 0) 1199 goto out; 1200 } 1201 #ifdef PACKET_DEBUG 1202 fprintf(stderr, "encrypted: "); 1203 sshbuf_dump(state->output, stderr); 1204 #endif 1205 /* increment sequence number for outgoing packets */ 1206 if (++state->p_send.seqnr == 0) 1207 logit("outgoing seqnr wraps around"); 1208 if (++state->p_send.packets == 0) 1209 if (!(ssh->compat & SSH_BUG_NOREKEY)) 1210 return SSH_ERR_NEED_REKEY; 1211 state->p_send.blocks += len / block_size; 1212 state->p_send.bytes += len; 1213 sshbuf_reset(state->outgoing_packet); 1214 1215 if (type == SSH2_MSG_NEWKEYS) 1216 r = ssh_set_newkeys(ssh, MODE_OUT); 1217 else if (type == SSH2_MSG_USERAUTH_SUCCESS && state->server_side) 1218 r = ssh_packet_enable_delayed_compress(ssh); 1219 else 1220 r = 0; 1221 out: 1222 return r; 1223 } 1224 1225 /* returns non-zero if the specified packet type is usec by KEX */ 1226 static int 1227 ssh_packet_type_is_kex(u_char type) 1228 { 1229 return 1230 type >= SSH2_MSG_TRANSPORT_MIN && 1231 type <= SSH2_MSG_TRANSPORT_MAX && 1232 type != SSH2_MSG_SERVICE_REQUEST && 1233 type != SSH2_MSG_SERVICE_ACCEPT && 1234 type != SSH2_MSG_EXT_INFO; 1235 } 1236 1237 int 1238 ssh_packet_send2(struct ssh *ssh) 1239 { 1240 struct session_state *state = ssh->state; 1241 struct packet *p; 1242 u_char type; 1243 int r, need_rekey; 1244 1245 if (sshbuf_len(state->outgoing_packet) < 6) 1246 return SSH_ERR_INTERNAL_ERROR; 1247 type = sshbuf_ptr(state->outgoing_packet)[5]; 1248 need_rekey = !ssh_packet_type_is_kex(type) && 1249 ssh_packet_need_rekeying(ssh, sshbuf_len(state->outgoing_packet)); 1250 1251 /* 1252 * During rekeying we can only send key exchange messages. 1253 * Queue everything else. 1254 */ 1255 if ((need_rekey || state->rekeying) && !ssh_packet_type_is_kex(type)) { 1256 if (need_rekey) 1257 debug3("%s: rekex triggered", __func__); 1258 debug("enqueue packet: %u", type); 1259 p = calloc(1, sizeof(*p)); 1260 if (p == NULL) 1261 return SSH_ERR_ALLOC_FAIL; 1262 p->type = type; 1263 p->payload = state->outgoing_packet; 1264 TAILQ_INSERT_TAIL(&state->outgoing, p, next); 1265 state->outgoing_packet = sshbuf_new(); 1266 if (state->outgoing_packet == NULL) 1267 return SSH_ERR_ALLOC_FAIL; 1268 if (need_rekey) { 1269 /* 1270 * This packet triggered a rekey, so send the 1271 * KEXINIT now. 1272 * NB. reenters this function via kex_start_rekex(). 1273 */ 1274 return kex_start_rekex(ssh); 1275 } 1276 return 0; 1277 } 1278 1279 /* rekeying starts with sending KEXINIT */ 1280 if (type == SSH2_MSG_KEXINIT) 1281 state->rekeying = 1; 1282 1283 if ((r = ssh_packet_send2_wrapped(ssh)) != 0) 1284 return r; 1285 1286 /* after a NEWKEYS message we can send the complete queue */ 1287 if (type == SSH2_MSG_NEWKEYS) { 1288 state->rekeying = 0; 1289 state->rekey_time = monotime(); 1290 while ((p = TAILQ_FIRST(&state->outgoing))) { 1291 type = p->type; 1292 /* 1293 * If this packet triggers a rekex, then skip the 1294 * remaining packets in the queue for now. 1295 * NB. re-enters this function via kex_start_rekex. 1296 */ 1297 if (ssh_packet_need_rekeying(ssh, 1298 sshbuf_len(p->payload))) { 1299 debug3("%s: queued packet triggered rekex", 1300 __func__); 1301 return kex_start_rekex(ssh); 1302 } 1303 debug("dequeue packet: %u", type); 1304 sshbuf_free(state->outgoing_packet); 1305 state->outgoing_packet = p->payload; 1306 TAILQ_REMOVE(&state->outgoing, p, next); 1307 memset(p, 0, sizeof(*p)); 1308 free(p); 1309 if ((r = ssh_packet_send2_wrapped(ssh)) != 0) 1310 return r; 1311 } 1312 } 1313 return 0; 1314 } 1315 1316 /* 1317 * Waits until a packet has been received, and returns its type. Note that 1318 * no other data is processed until this returns, so this function should not 1319 * be used during the interactive session. 1320 */ 1321 1322 int 1323 ssh_packet_read_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1324 { 1325 struct session_state *state = ssh->state; 1326 int len, r, ms_remain; 1327 fd_set *setp; 1328 char buf[8192]; 1329 struct timeval timeout, start, *timeoutp = NULL; 1330 1331 DBG(debug("packet_read()")); 1332 1333 setp = calloc(howmany(state->connection_in + 1, 1334 NFDBITS), sizeof(fd_mask)); 1335 if (setp == NULL) 1336 return SSH_ERR_ALLOC_FAIL; 1337 1338 /* 1339 * Since we are blocking, ensure that all written packets have 1340 * been sent. 1341 */ 1342 if ((r = ssh_packet_write_wait(ssh)) != 0) 1343 goto out; 1344 1345 /* Stay in the loop until we have received a complete packet. */ 1346 for (;;) { 1347 /* Try to read a packet from the buffer. */ 1348 r = ssh_packet_read_poll_seqnr(ssh, typep, seqnr_p); 1349 if (r != 0) 1350 break; 1351 /* If we got a packet, return it. */ 1352 if (*typep != SSH_MSG_NONE) 1353 break; 1354 /* 1355 * Otherwise, wait for some data to arrive, add it to the 1356 * buffer, and try again. 1357 */ 1358 memset(setp, 0, howmany(state->connection_in + 1, 1359 NFDBITS) * sizeof(fd_mask)); 1360 FD_SET(state->connection_in, setp); 1361 1362 if (state->packet_timeout_ms > 0) { 1363 ms_remain = state->packet_timeout_ms; 1364 timeoutp = &timeout; 1365 } 1366 /* Wait for some data to arrive. */ 1367 for (;;) { 1368 if (state->packet_timeout_ms > 0) { 1369 ms_to_timeval(&timeout, ms_remain); 1370 monotime_tv(&start); 1371 } 1372 if ((r = select(state->connection_in + 1, setp, 1373 NULL, NULL, timeoutp)) >= 0) 1374 break; 1375 if (errno != EAGAIN && errno != EINTR && 1376 errno != EWOULDBLOCK) { 1377 r = SSH_ERR_SYSTEM_ERROR; 1378 goto out; 1379 } 1380 if (state->packet_timeout_ms <= 0) 1381 continue; 1382 ms_subtract_diff(&start, &ms_remain); 1383 if (ms_remain <= 0) { 1384 r = 0; 1385 break; 1386 } 1387 } 1388 if (r == 0) { 1389 r = SSH_ERR_CONN_TIMEOUT; 1390 goto out; 1391 } 1392 /* Read data from the socket. */ 1393 len = read(state->connection_in, buf, sizeof(buf)); 1394 if (len == 0) { 1395 r = SSH_ERR_CONN_CLOSED; 1396 goto out; 1397 } 1398 if (len == -1) { 1399 r = SSH_ERR_SYSTEM_ERROR; 1400 goto out; 1401 } 1402 1403 /* Append it to the buffer. */ 1404 if ((r = ssh_packet_process_incoming(ssh, buf, len)) != 0) 1405 goto out; 1406 } 1407 out: 1408 free(setp); 1409 return r; 1410 } 1411 1412 int 1413 ssh_packet_read(struct ssh *ssh) 1414 { 1415 u_char type; 1416 int r; 1417 1418 if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0) 1419 fatal("%s: %s", __func__, ssh_err(r)); 1420 return type; 1421 } 1422 1423 /* 1424 * Waits until a packet has been received, verifies that its type matches 1425 * that given, and gives a fatal error and exits if there is a mismatch. 1426 */ 1427 1428 int 1429 ssh_packet_read_expect(struct ssh *ssh, u_int expected_type) 1430 { 1431 int r; 1432 u_char type; 1433 1434 if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0) 1435 return r; 1436 if (type != expected_type) { 1437 if ((r = sshpkt_disconnect(ssh, 1438 "Protocol error: expected packet type %d, got %d", 1439 expected_type, type)) != 0) 1440 return r; 1441 return SSH_ERR_PROTOCOL_ERROR; 1442 } 1443 return 0; 1444 } 1445 1446 static int 1447 ssh_packet_read_poll2_mux(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1448 { 1449 struct session_state *state = ssh->state; 1450 const u_char *cp; 1451 size_t need; 1452 int r; 1453 1454 if (ssh->kex) 1455 return SSH_ERR_INTERNAL_ERROR; 1456 *typep = SSH_MSG_NONE; 1457 cp = sshbuf_ptr(state->input); 1458 if (state->packlen == 0) { 1459 if (sshbuf_len(state->input) < 4 + 1) 1460 return 0; /* packet is incomplete */ 1461 state->packlen = PEEK_U32(cp); 1462 if (state->packlen < 4 + 1 || 1463 state->packlen > PACKET_MAX_SIZE) 1464 return SSH_ERR_MESSAGE_INCOMPLETE; 1465 } 1466 need = state->packlen + 4; 1467 if (sshbuf_len(state->input) < need) 1468 return 0; /* packet is incomplete */ 1469 sshbuf_reset(state->incoming_packet); 1470 if ((r = sshbuf_put(state->incoming_packet, cp + 4, 1471 state->packlen)) != 0 || 1472 (r = sshbuf_consume(state->input, need)) != 0 || 1473 (r = sshbuf_get_u8(state->incoming_packet, NULL)) != 0 || 1474 (r = sshbuf_get_u8(state->incoming_packet, typep)) != 0) 1475 return r; 1476 if (ssh_packet_log_type(*typep)) 1477 debug3("%s: type %u", __func__, *typep); 1478 /* sshbuf_dump(state->incoming_packet, stderr); */ 1479 /* reset for next packet */ 1480 state->packlen = 0; 1481 return r; 1482 } 1483 1484 int 1485 ssh_packet_read_poll2(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1486 { 1487 struct session_state *state = ssh->state; 1488 u_int padlen, need; 1489 u_char *cp; 1490 u_int maclen, aadlen = 0, authlen = 0, block_size; 1491 struct sshenc *enc = NULL; 1492 struct sshmac *mac = NULL; 1493 struct sshcomp *comp = NULL; 1494 int r; 1495 1496 if (state->mux) 1497 return ssh_packet_read_poll2_mux(ssh, typep, seqnr_p); 1498 1499 *typep = SSH_MSG_NONE; 1500 1501 if (state->packet_discard) 1502 return 0; 1503 1504 if (state->newkeys[MODE_IN] != NULL) { 1505 enc = &state->newkeys[MODE_IN]->enc; 1506 mac = &state->newkeys[MODE_IN]->mac; 1507 comp = &state->newkeys[MODE_IN]->comp; 1508 /* disable mac for authenticated encryption */ 1509 if ((authlen = cipher_authlen(enc->cipher)) != 0) 1510 mac = NULL; 1511 } 1512 maclen = mac && mac->enabled ? mac->mac_len : 0; 1513 block_size = enc ? enc->block_size : 8; 1514 aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0; 1515 1516 if (aadlen && state->packlen == 0) { 1517 if (cipher_get_length(state->receive_context, 1518 &state->packlen, state->p_read.seqnr, 1519 sshbuf_ptr(state->input), sshbuf_len(state->input)) != 0) 1520 return 0; 1521 if (state->packlen < 1 + 4 || 1522 state->packlen > PACKET_MAX_SIZE) { 1523 #ifdef PACKET_DEBUG 1524 sshbuf_dump(state->input, stderr); 1525 #endif 1526 logit("Bad packet length %u.", state->packlen); 1527 if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0) 1528 return r; 1529 return SSH_ERR_CONN_CORRUPT; 1530 } 1531 sshbuf_reset(state->incoming_packet); 1532 } else if (state->packlen == 0) { 1533 /* 1534 * check if input size is less than the cipher block size, 1535 * decrypt first block and extract length of incoming packet 1536 */ 1537 if (sshbuf_len(state->input) < block_size) 1538 return 0; 1539 sshbuf_reset(state->incoming_packet); 1540 if ((r = sshbuf_reserve(state->incoming_packet, block_size, 1541 &cp)) != 0) 1542 goto out; 1543 if ((r = cipher_crypt(state->receive_context, 1544 state->p_send.seqnr, cp, sshbuf_ptr(state->input), 1545 block_size, 0, 0)) != 0) 1546 goto out; 1547 state->packlen = PEEK_U32(sshbuf_ptr(state->incoming_packet)); 1548 if (state->packlen < 1 + 4 || 1549 state->packlen > PACKET_MAX_SIZE) { 1550 #ifdef PACKET_DEBUG 1551 fprintf(stderr, "input: \n"); 1552 sshbuf_dump(state->input, stderr); 1553 fprintf(stderr, "incoming_packet: \n"); 1554 sshbuf_dump(state->incoming_packet, stderr); 1555 #endif 1556 logit("Bad packet length %u.", state->packlen); 1557 return ssh_packet_start_discard(ssh, enc, mac, 0, 1558 PACKET_MAX_SIZE); 1559 } 1560 if ((r = sshbuf_consume(state->input, block_size)) != 0) 1561 goto out; 1562 } 1563 DBG(debug("input: packet len %u", state->packlen+4)); 1564 1565 if (aadlen) { 1566 /* only the payload is encrypted */ 1567 need = state->packlen; 1568 } else { 1569 /* 1570 * the payload size and the payload are encrypted, but we 1571 * have a partial packet of block_size bytes 1572 */ 1573 need = 4 + state->packlen - block_size; 1574 } 1575 DBG(debug("partial packet: block %d, need %d, maclen %d, authlen %d," 1576 " aadlen %d", block_size, need, maclen, authlen, aadlen)); 1577 if (need % block_size != 0) { 1578 logit("padding error: need %d block %d mod %d", 1579 need, block_size, need % block_size); 1580 return ssh_packet_start_discard(ssh, enc, mac, 0, 1581 PACKET_MAX_SIZE - block_size); 1582 } 1583 /* 1584 * check if the entire packet has been received and 1585 * decrypt into incoming_packet: 1586 * 'aadlen' bytes are unencrypted, but authenticated. 1587 * 'need' bytes are encrypted, followed by either 1588 * 'authlen' bytes of authentication tag or 1589 * 'maclen' bytes of message authentication code. 1590 */ 1591 if (sshbuf_len(state->input) < aadlen + need + authlen + maclen) 1592 return 0; /* packet is incomplete */ 1593 #ifdef PACKET_DEBUG 1594 fprintf(stderr, "read_poll enc/full: "); 1595 sshbuf_dump(state->input, stderr); 1596 #endif 1597 /* EtM: check mac over encrypted input */ 1598 if (mac && mac->enabled && mac->etm) { 1599 if ((r = mac_check(mac, state->p_read.seqnr, 1600 sshbuf_ptr(state->input), aadlen + need, 1601 sshbuf_ptr(state->input) + aadlen + need + authlen, 1602 maclen)) != 0) { 1603 if (r == SSH_ERR_MAC_INVALID) 1604 logit("Corrupted MAC on input."); 1605 goto out; 1606 } 1607 } 1608 if ((r = sshbuf_reserve(state->incoming_packet, aadlen + need, 1609 &cp)) != 0) 1610 goto out; 1611 if ((r = cipher_crypt(state->receive_context, state->p_read.seqnr, cp, 1612 sshbuf_ptr(state->input), need, aadlen, authlen)) != 0) 1613 goto out; 1614 if ((r = sshbuf_consume(state->input, aadlen + need + authlen)) != 0) 1615 goto out; 1616 if (mac && mac->enabled) { 1617 /* Not EtM: check MAC over cleartext */ 1618 if (!mac->etm && (r = mac_check(mac, state->p_read.seqnr, 1619 sshbuf_ptr(state->incoming_packet), 1620 sshbuf_len(state->incoming_packet), 1621 sshbuf_ptr(state->input), maclen)) != 0) { 1622 if (r != SSH_ERR_MAC_INVALID) 1623 goto out; 1624 logit("Corrupted MAC on input."); 1625 if (need + block_size > PACKET_MAX_SIZE) 1626 return SSH_ERR_INTERNAL_ERROR; 1627 return ssh_packet_start_discard(ssh, enc, mac, 1628 sshbuf_len(state->incoming_packet), 1629 PACKET_MAX_SIZE - need - block_size); 1630 } 1631 /* Remove MAC from input buffer */ 1632 DBG(debug("MAC #%d ok", state->p_read.seqnr)); 1633 if ((r = sshbuf_consume(state->input, mac->mac_len)) != 0) 1634 goto out; 1635 } 1636 if (seqnr_p != NULL) 1637 *seqnr_p = state->p_read.seqnr; 1638 if (++state->p_read.seqnr == 0) 1639 logit("incoming seqnr wraps around"); 1640 if (++state->p_read.packets == 0) 1641 if (!(ssh->compat & SSH_BUG_NOREKEY)) 1642 return SSH_ERR_NEED_REKEY; 1643 state->p_read.blocks += (state->packlen + 4) / block_size; 1644 state->p_read.bytes += state->packlen + 4; 1645 1646 /* get padlen */ 1647 padlen = sshbuf_ptr(state->incoming_packet)[4]; 1648 DBG(debug("input: padlen %d", padlen)); 1649 if (padlen < 4) { 1650 if ((r = sshpkt_disconnect(ssh, 1651 "Corrupted padlen %d on input.", padlen)) != 0 || 1652 (r = ssh_packet_write_wait(ssh)) != 0) 1653 return r; 1654 return SSH_ERR_CONN_CORRUPT; 1655 } 1656 1657 /* skip packet size + padlen, discard padding */ 1658 if ((r = sshbuf_consume(state->incoming_packet, 4 + 1)) != 0 || 1659 ((r = sshbuf_consume_end(state->incoming_packet, padlen)) != 0)) 1660 goto out; 1661 1662 DBG(debug("input: len before de-compress %zd", 1663 sshbuf_len(state->incoming_packet))); 1664 if (comp && comp->enabled) { 1665 sshbuf_reset(state->compression_buffer); 1666 if ((r = uncompress_buffer(ssh, state->incoming_packet, 1667 state->compression_buffer)) != 0) 1668 goto out; 1669 sshbuf_reset(state->incoming_packet); 1670 if ((r = sshbuf_putb(state->incoming_packet, 1671 state->compression_buffer)) != 0) 1672 goto out; 1673 DBG(debug("input: len after de-compress %zd", 1674 sshbuf_len(state->incoming_packet))); 1675 } 1676 /* 1677 * get packet type, implies consume. 1678 * return length of payload (without type field) 1679 */ 1680 if ((r = sshbuf_get_u8(state->incoming_packet, typep)) != 0) 1681 goto out; 1682 if (ssh_packet_log_type(*typep)) 1683 debug3("receive packet: type %u", *typep); 1684 if (*typep < SSH2_MSG_MIN || *typep >= SSH2_MSG_LOCAL_MIN) { 1685 if ((r = sshpkt_disconnect(ssh, 1686 "Invalid ssh2 packet type: %d", *typep)) != 0 || 1687 (r = ssh_packet_write_wait(ssh)) != 0) 1688 return r; 1689 return SSH_ERR_PROTOCOL_ERROR; 1690 } 1691 if (state->hook_in != NULL && 1692 (r = state->hook_in(ssh, state->incoming_packet, typep, 1693 state->hook_in_ctx)) != 0) 1694 return r; 1695 if (*typep == SSH2_MSG_USERAUTH_SUCCESS && !state->server_side) 1696 r = ssh_packet_enable_delayed_compress(ssh); 1697 else 1698 r = 0; 1699 #ifdef PACKET_DEBUG 1700 fprintf(stderr, "read/plain[%d]:\r\n", *typep); 1701 sshbuf_dump(state->incoming_packet, stderr); 1702 #endif 1703 /* reset for next packet */ 1704 state->packlen = 0; 1705 1706 /* do we need to rekey? */ 1707 if (ssh_packet_need_rekeying(ssh, 0)) { 1708 debug3("%s: rekex triggered", __func__); 1709 if ((r = kex_start_rekex(ssh)) != 0) 1710 return r; 1711 } 1712 out: 1713 return r; 1714 } 1715 1716 int 1717 ssh_packet_read_poll_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1718 { 1719 struct session_state *state = ssh->state; 1720 u_int reason, seqnr; 1721 int r; 1722 u_char *msg; 1723 1724 for (;;) { 1725 msg = NULL; 1726 r = ssh_packet_read_poll2(ssh, typep, seqnr_p); 1727 if (r != 0) 1728 return r; 1729 if (*typep) { 1730 state->keep_alive_timeouts = 0; 1731 DBG(debug("received packet type %d", *typep)); 1732 } 1733 switch (*typep) { 1734 case SSH2_MSG_IGNORE: 1735 debug3("Received SSH2_MSG_IGNORE"); 1736 break; 1737 case SSH2_MSG_DEBUG: 1738 if ((r = sshpkt_get_u8(ssh, NULL)) != 0 || 1739 (r = sshpkt_get_string(ssh, &msg, NULL)) != 0 || 1740 (r = sshpkt_get_string(ssh, NULL, NULL)) != 0) { 1741 free(msg); 1742 return r; 1743 } 1744 debug("Remote: %.900s", msg); 1745 free(msg); 1746 break; 1747 case SSH2_MSG_DISCONNECT: 1748 if ((r = sshpkt_get_u32(ssh, &reason)) != 0 || 1749 (r = sshpkt_get_string(ssh, &msg, NULL)) != 0) 1750 return r; 1751 /* Ignore normal client exit notifications */ 1752 do_log2(ssh->state->server_side && 1753 reason == SSH2_DISCONNECT_BY_APPLICATION ? 1754 SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_ERROR, 1755 "Received disconnect from %s port %d:" 1756 "%u: %.400s", ssh_remote_ipaddr(ssh), 1757 ssh_remote_port(ssh), reason, msg); 1758 free(msg); 1759 return SSH_ERR_DISCONNECTED; 1760 case SSH2_MSG_UNIMPLEMENTED: 1761 if ((r = sshpkt_get_u32(ssh, &seqnr)) != 0) 1762 return r; 1763 debug("Received SSH2_MSG_UNIMPLEMENTED for %u", 1764 seqnr); 1765 break; 1766 default: 1767 return 0; 1768 } 1769 } 1770 } 1771 1772 /* 1773 * Buffers the given amount of input characters. This is intended to be used 1774 * together with packet_read_poll. 1775 */ 1776 1777 int 1778 ssh_packet_process_incoming(struct ssh *ssh, const char *buf, u_int len) 1779 { 1780 struct session_state *state = ssh->state; 1781 int r; 1782 1783 if (state->packet_discard) { 1784 state->keep_alive_timeouts = 0; /* ?? */ 1785 if (len >= state->packet_discard) { 1786 if ((r = ssh_packet_stop_discard(ssh)) != 0) 1787 return r; 1788 } 1789 state->packet_discard -= len; 1790 return 0; 1791 } 1792 if ((r = sshbuf_put(ssh->state->input, buf, len)) != 0) 1793 return r; 1794 1795 return 0; 1796 } 1797 1798 int 1799 ssh_packet_remaining(struct ssh *ssh) 1800 { 1801 return sshbuf_len(ssh->state->incoming_packet); 1802 } 1803 1804 /* 1805 * Sends a diagnostic message from the server to the client. This message 1806 * can be sent at any time (but not while constructing another message). The 1807 * message is printed immediately, but only if the client is being executed 1808 * in verbose mode. These messages are primarily intended to ease debugging 1809 * authentication problems. The length of the formatted message must not 1810 * exceed 1024 bytes. This will automatically call ssh_packet_write_wait. 1811 */ 1812 void 1813 ssh_packet_send_debug(struct ssh *ssh, const char *fmt,...) 1814 { 1815 char buf[1024]; 1816 va_list args; 1817 int r; 1818 1819 if ((ssh->compat & SSH_BUG_DEBUG)) 1820 return; 1821 1822 va_start(args, fmt); 1823 vsnprintf(buf, sizeof(buf), fmt, args); 1824 va_end(args); 1825 1826 debug3("sending debug message: %s", buf); 1827 1828 if ((r = sshpkt_start(ssh, SSH2_MSG_DEBUG)) != 0 || 1829 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* always display */ 1830 (r = sshpkt_put_cstring(ssh, buf)) != 0 || 1831 (r = sshpkt_put_cstring(ssh, "")) != 0 || 1832 (r = sshpkt_send(ssh)) != 0 || 1833 (r = ssh_packet_write_wait(ssh)) != 0) 1834 fatal("%s: %s", __func__, ssh_err(r)); 1835 } 1836 1837 void 1838 sshpkt_fmt_connection_id(struct ssh *ssh, char *s, size_t l) 1839 { 1840 snprintf(s, l, "%.200s%s%s port %d", 1841 ssh->log_preamble ? ssh->log_preamble : "", 1842 ssh->log_preamble ? " " : "", 1843 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 1844 } 1845 1846 /* 1847 * Pretty-print connection-terminating errors and exit. 1848 */ 1849 static void 1850 sshpkt_vfatal(struct ssh *ssh, int r, const char *fmt, va_list ap) 1851 { 1852 char *tag = NULL, remote_id[512]; 1853 int oerrno = errno; 1854 1855 sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id)); 1856 1857 switch (r) { 1858 case SSH_ERR_CONN_CLOSED: 1859 ssh_packet_clear_keys(ssh); 1860 logdie("Connection closed by %s", remote_id); 1861 case SSH_ERR_CONN_TIMEOUT: 1862 ssh_packet_clear_keys(ssh); 1863 logdie("Connection %s %s timed out", 1864 ssh->state->server_side ? "from" : "to", remote_id); 1865 case SSH_ERR_DISCONNECTED: 1866 ssh_packet_clear_keys(ssh); 1867 logdie("Disconnected from %s", remote_id); 1868 case SSH_ERR_SYSTEM_ERROR: 1869 if (errno == ECONNRESET) { 1870 ssh_packet_clear_keys(ssh); 1871 logdie("Connection reset by %s", remote_id); 1872 } 1873 /* FALLTHROUGH */ 1874 case SSH_ERR_NO_CIPHER_ALG_MATCH: 1875 case SSH_ERR_NO_MAC_ALG_MATCH: 1876 case SSH_ERR_NO_COMPRESS_ALG_MATCH: 1877 case SSH_ERR_NO_KEX_ALG_MATCH: 1878 case SSH_ERR_NO_HOSTKEY_ALG_MATCH: 1879 if (ssh && ssh->kex && ssh->kex->failed_choice) { 1880 ssh_packet_clear_keys(ssh); 1881 errno = oerrno; 1882 logdie("Unable to negotiate with %s: %s. " 1883 "Their offer: %s", remote_id, ssh_err(r), 1884 ssh->kex->failed_choice); 1885 } 1886 /* FALLTHROUGH */ 1887 default: 1888 if (vasprintf(&tag, fmt, ap) == -1) { 1889 ssh_packet_clear_keys(ssh); 1890 logdie("%s: could not allocate failure message", 1891 __func__); 1892 } 1893 ssh_packet_clear_keys(ssh); 1894 errno = oerrno; 1895 logdie("%s%sConnection %s %s: %s", 1896 tag != NULL ? tag : "", tag != NULL ? ": " : "", 1897 ssh->state->server_side ? "from" : "to", 1898 remote_id, ssh_err(r)); 1899 } 1900 } 1901 1902 void 1903 sshpkt_fatal(struct ssh *ssh, int r, const char *fmt, ...) 1904 { 1905 va_list ap; 1906 1907 va_start(ap, fmt); 1908 sshpkt_vfatal(ssh, r, fmt, ap); 1909 /* NOTREACHED */ 1910 va_end(ap); 1911 logdie("%s: should have exited", __func__); 1912 } 1913 1914 /* 1915 * Logs the error plus constructs and sends a disconnect packet, closes the 1916 * connection, and exits. This function never returns. The error message 1917 * should not contain a newline. The length of the formatted message must 1918 * not exceed 1024 bytes. 1919 */ 1920 void 1921 ssh_packet_disconnect(struct ssh *ssh, const char *fmt,...) 1922 { 1923 char buf[1024], remote_id[512]; 1924 va_list args; 1925 static int disconnecting = 0; 1926 int r; 1927 1928 if (disconnecting) /* Guard against recursive invocations. */ 1929 fatal("packet_disconnect called recursively."); 1930 disconnecting = 1; 1931 1932 /* 1933 * Format the message. Note that the caller must make sure the 1934 * message is of limited size. 1935 */ 1936 sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id)); 1937 va_start(args, fmt); 1938 vsnprintf(buf, sizeof(buf), fmt, args); 1939 va_end(args); 1940 1941 /* Display the error locally */ 1942 logit("Disconnecting %s: %.100s", remote_id, buf); 1943 1944 /* 1945 * Send the disconnect message to the other side, and wait 1946 * for it to get sent. 1947 */ 1948 if ((r = sshpkt_disconnect(ssh, "%s", buf)) != 0) 1949 sshpkt_fatal(ssh, r, "%s", __func__); 1950 1951 if ((r = ssh_packet_write_wait(ssh)) != 0) 1952 sshpkt_fatal(ssh, r, "%s", __func__); 1953 1954 /* Close the connection. */ 1955 ssh_packet_close(ssh); 1956 cleanup_exit(255); 1957 } 1958 1959 /* 1960 * Checks if there is any buffered output, and tries to write some of 1961 * the output. 1962 */ 1963 int 1964 ssh_packet_write_poll(struct ssh *ssh) 1965 { 1966 struct session_state *state = ssh->state; 1967 int len = sshbuf_len(state->output); 1968 int r; 1969 1970 if (len > 0) { 1971 len = write(state->connection_out, 1972 sshbuf_ptr(state->output), len); 1973 if (len == -1) { 1974 if (errno == EINTR || errno == EAGAIN || 1975 errno == EWOULDBLOCK) 1976 return 0; 1977 return SSH_ERR_SYSTEM_ERROR; 1978 } 1979 if (len == 0) 1980 return SSH_ERR_CONN_CLOSED; 1981 if ((r = sshbuf_consume(state->output, len)) != 0) 1982 return r; 1983 } 1984 return 0; 1985 } 1986 1987 /* 1988 * Calls packet_write_poll repeatedly until all pending output data has been 1989 * written. 1990 */ 1991 int 1992 ssh_packet_write_wait(struct ssh *ssh) 1993 { 1994 fd_set *setp; 1995 int ret, r, ms_remain = 0; 1996 struct timeval start, timeout, *timeoutp = NULL; 1997 struct session_state *state = ssh->state; 1998 1999 setp = calloc(howmany(state->connection_out + 1, 2000 NFDBITS), sizeof(fd_mask)); 2001 if (setp == NULL) 2002 return SSH_ERR_ALLOC_FAIL; 2003 if ((r = ssh_packet_write_poll(ssh)) != 0) { 2004 free(setp); 2005 return r; 2006 } 2007 while (ssh_packet_have_data_to_write(ssh)) { 2008 memset(setp, 0, howmany(state->connection_out + 1, 2009 NFDBITS) * sizeof(fd_mask)); 2010 FD_SET(state->connection_out, setp); 2011 2012 if (state->packet_timeout_ms > 0) { 2013 ms_remain = state->packet_timeout_ms; 2014 timeoutp = &timeout; 2015 } 2016 for (;;) { 2017 if (state->packet_timeout_ms > 0) { 2018 ms_to_timeval(&timeout, ms_remain); 2019 monotime_tv(&start); 2020 } 2021 if ((ret = select(state->connection_out + 1, 2022 NULL, setp, NULL, timeoutp)) >= 0) 2023 break; 2024 if (errno != EAGAIN && errno != EINTR && 2025 errno != EWOULDBLOCK) 2026 break; 2027 if (state->packet_timeout_ms <= 0) 2028 continue; 2029 ms_subtract_diff(&start, &ms_remain); 2030 if (ms_remain <= 0) { 2031 ret = 0; 2032 break; 2033 } 2034 } 2035 if (ret == 0) { 2036 free(setp); 2037 return SSH_ERR_CONN_TIMEOUT; 2038 } 2039 if ((r = ssh_packet_write_poll(ssh)) != 0) { 2040 free(setp); 2041 return r; 2042 } 2043 } 2044 free(setp); 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 #ifndef IP_TOS_IS_BROKEN 2071 if (!ssh_packet_connection_is_on_socket(ssh) || tos == INT_MAX) 2072 return; 2073 switch (ssh_packet_connection_af(ssh)) { 2074 # ifdef IP_TOS 2075 case AF_INET: 2076 debug3("%s: set IP_TOS 0x%02x", __func__, tos); 2077 if (setsockopt(ssh->state->connection_in, 2078 IPPROTO_IP, IP_TOS, &tos, sizeof(tos)) == -1) 2079 error("setsockopt IP_TOS %d: %.100s:", 2080 tos, strerror(errno)); 2081 break; 2082 # endif /* IP_TOS */ 2083 # ifdef IPV6_TCLASS 2084 case AF_INET6: 2085 debug3("%s: set IPV6_TCLASS 0x%02x", __func__, tos); 2086 if (setsockopt(ssh->state->connection_in, 2087 IPPROTO_IPV6, IPV6_TCLASS, &tos, sizeof(tos)) == -1) 2088 error("setsockopt IPV6_TCLASS %d: %.100s:", 2089 tos, strerror(errno)); 2090 break; 2091 # endif /* IPV6_TCLASS */ 2092 } 2093 #endif /* IP_TOS_IS_BROKEN */ 2094 } 2095 2096 /* Informs that the current session is interactive. Sets IP flags for that. */ 2097 2098 void 2099 ssh_packet_set_interactive(struct ssh *ssh, int interactive, int qos_interactive, int qos_bulk) 2100 { 2101 struct session_state *state = ssh->state; 2102 2103 if (state->set_interactive_called) 2104 return; 2105 state->set_interactive_called = 1; 2106 2107 /* Record that we are in interactive mode. */ 2108 state->interactive_mode = interactive; 2109 2110 /* Only set socket options if using a socket. */ 2111 if (!ssh_packet_connection_is_on_socket(ssh)) 2112 return; 2113 set_nodelay(state->connection_in); 2114 ssh_packet_set_tos(ssh, interactive ? qos_interactive : 2115 qos_bulk); 2116 } 2117 2118 /* Returns true if the current connection is interactive. */ 2119 2120 int 2121 ssh_packet_is_interactive(struct ssh *ssh) 2122 { 2123 return ssh->state->interactive_mode; 2124 } 2125 2126 int 2127 ssh_packet_set_maxsize(struct ssh *ssh, u_int s) 2128 { 2129 struct session_state *state = ssh->state; 2130 2131 if (state->set_maxsize_called) { 2132 logit("packet_set_maxsize: called twice: old %d new %d", 2133 state->max_packet_size, s); 2134 return -1; 2135 } 2136 if (s < 4 * 1024 || s > 1024 * 1024) { 2137 logit("packet_set_maxsize: bad size %d", s); 2138 return -1; 2139 } 2140 state->set_maxsize_called = 1; 2141 debug("packet_set_maxsize: setting to %d", s); 2142 state->max_packet_size = s; 2143 return s; 2144 } 2145 2146 int 2147 ssh_packet_inc_alive_timeouts(struct ssh *ssh) 2148 { 2149 return ++ssh->state->keep_alive_timeouts; 2150 } 2151 2152 void 2153 ssh_packet_set_alive_timeouts(struct ssh *ssh, int ka) 2154 { 2155 ssh->state->keep_alive_timeouts = ka; 2156 } 2157 2158 u_int 2159 ssh_packet_get_maxsize(struct ssh *ssh) 2160 { 2161 return ssh->state->max_packet_size; 2162 } 2163 2164 void 2165 ssh_packet_set_rekey_limits(struct ssh *ssh, u_int64_t bytes, u_int32_t seconds) 2166 { 2167 debug3("rekey after %llu bytes, %u seconds", (unsigned long long)bytes, 2168 (unsigned int)seconds); 2169 ssh->state->rekey_limit = bytes; 2170 ssh->state->rekey_interval = seconds; 2171 } 2172 2173 time_t 2174 ssh_packet_get_rekey_timeout(struct ssh *ssh) 2175 { 2176 time_t seconds; 2177 2178 seconds = ssh->state->rekey_time + ssh->state->rekey_interval - 2179 monotime(); 2180 return (seconds <= 0 ? 1 : seconds); 2181 } 2182 2183 void 2184 ssh_packet_set_server(struct ssh *ssh) 2185 { 2186 ssh->state->server_side = 1; 2187 ssh->kex->server = 1; /* XXX unify? */ 2188 } 2189 2190 void 2191 ssh_packet_set_authenticated(struct ssh *ssh) 2192 { 2193 ssh->state->after_authentication = 1; 2194 } 2195 2196 void * 2197 ssh_packet_get_input(struct ssh *ssh) 2198 { 2199 return (void *)ssh->state->input; 2200 } 2201 2202 void * 2203 ssh_packet_get_output(struct ssh *ssh) 2204 { 2205 return (void *)ssh->state->output; 2206 } 2207 2208 /* Reset after_authentication and reset compression in post-auth privsep */ 2209 static int 2210 ssh_packet_set_postauth(struct ssh *ssh) 2211 { 2212 int r; 2213 2214 debug("%s: called", __func__); 2215 /* This was set in net child, but is not visible in user child */ 2216 ssh->state->after_authentication = 1; 2217 ssh->state->rekeying = 0; 2218 if ((r = ssh_packet_enable_delayed_compress(ssh)) != 0) 2219 return r; 2220 return 0; 2221 } 2222 2223 /* Packet state (de-)serialization for privsep */ 2224 2225 /* turn kex into a blob for packet state serialization */ 2226 static int 2227 kex_to_blob(struct sshbuf *m, struct kex *kex) 2228 { 2229 int r; 2230 2231 if ((r = sshbuf_put_string(m, kex->session_id, 2232 kex->session_id_len)) != 0 || 2233 (r = sshbuf_put_u32(m, kex->we_need)) != 0 || 2234 (r = sshbuf_put_cstring(m, kex->hostkey_alg)) != 0 || 2235 (r = sshbuf_put_u32(m, kex->hostkey_type)) != 0 || 2236 (r = sshbuf_put_u32(m, kex->hostkey_nid)) != 0 || 2237 (r = sshbuf_put_u32(m, kex->kex_type)) != 0 || 2238 (r = sshbuf_put_stringb(m, kex->my)) != 0 || 2239 (r = sshbuf_put_stringb(m, kex->peer)) != 0 || 2240 (r = sshbuf_put_stringb(m, kex->client_version)) != 0 || 2241 (r = sshbuf_put_stringb(m, kex->server_version)) != 0 || 2242 (r = sshbuf_put_u32(m, kex->flags)) != 0) 2243 return r; 2244 return 0; 2245 } 2246 2247 /* turn key exchange results into a blob for packet state serialization */ 2248 static int 2249 newkeys_to_blob(struct sshbuf *m, struct ssh *ssh, int mode) 2250 { 2251 struct sshbuf *b; 2252 struct sshcipher_ctx *cc; 2253 struct sshcomp *comp; 2254 struct sshenc *enc; 2255 struct sshmac *mac; 2256 struct newkeys *newkey; 2257 int r; 2258 2259 if ((newkey = ssh->state->newkeys[mode]) == NULL) 2260 return SSH_ERR_INTERNAL_ERROR; 2261 enc = &newkey->enc; 2262 mac = &newkey->mac; 2263 comp = &newkey->comp; 2264 cc = (mode == MODE_OUT) ? ssh->state->send_context : 2265 ssh->state->receive_context; 2266 if ((r = cipher_get_keyiv(cc, enc->iv, enc->iv_len)) != 0) 2267 return r; 2268 if ((b = sshbuf_new()) == NULL) 2269 return SSH_ERR_ALLOC_FAIL; 2270 if ((r = sshbuf_put_cstring(b, enc->name)) != 0 || 2271 (r = sshbuf_put_u32(b, enc->enabled)) != 0 || 2272 (r = sshbuf_put_u32(b, enc->block_size)) != 0 || 2273 (r = sshbuf_put_string(b, enc->key, enc->key_len)) != 0 || 2274 (r = sshbuf_put_string(b, enc->iv, enc->iv_len)) != 0) 2275 goto out; 2276 if (cipher_authlen(enc->cipher) == 0) { 2277 if ((r = sshbuf_put_cstring(b, mac->name)) != 0 || 2278 (r = sshbuf_put_u32(b, mac->enabled)) != 0 || 2279 (r = sshbuf_put_string(b, mac->key, mac->key_len)) != 0) 2280 goto out; 2281 } 2282 if ((r = sshbuf_put_u32(b, comp->type)) != 0 || 2283 (r = sshbuf_put_cstring(b, comp->name)) != 0) 2284 goto out; 2285 r = sshbuf_put_stringb(m, b); 2286 out: 2287 sshbuf_free(b); 2288 return r; 2289 } 2290 2291 /* serialize packet state into a blob */ 2292 int 2293 ssh_packet_get_state(struct ssh *ssh, struct sshbuf *m) 2294 { 2295 struct session_state *state = ssh->state; 2296 int r; 2297 2298 if ((r = kex_to_blob(m, ssh->kex)) != 0 || 2299 (r = newkeys_to_blob(m, ssh, MODE_OUT)) != 0 || 2300 (r = newkeys_to_blob(m, ssh, MODE_IN)) != 0 || 2301 (r = sshbuf_put_u64(m, state->rekey_limit)) != 0 || 2302 (r = sshbuf_put_u32(m, state->rekey_interval)) != 0 || 2303 (r = sshbuf_put_u32(m, state->p_send.seqnr)) != 0 || 2304 (r = sshbuf_put_u64(m, state->p_send.blocks)) != 0 || 2305 (r = sshbuf_put_u32(m, state->p_send.packets)) != 0 || 2306 (r = sshbuf_put_u64(m, state->p_send.bytes)) != 0 || 2307 (r = sshbuf_put_u32(m, state->p_read.seqnr)) != 0 || 2308 (r = sshbuf_put_u64(m, state->p_read.blocks)) != 0 || 2309 (r = sshbuf_put_u32(m, state->p_read.packets)) != 0 || 2310 (r = sshbuf_put_u64(m, state->p_read.bytes)) != 0 || 2311 (r = sshbuf_put_stringb(m, state->input)) != 0 || 2312 (r = sshbuf_put_stringb(m, state->output)) != 0) 2313 return r; 2314 2315 return 0; 2316 } 2317 2318 /* restore key exchange results from blob for packet state de-serialization */ 2319 static int 2320 newkeys_from_blob(struct sshbuf *m, struct ssh *ssh, int mode) 2321 { 2322 struct sshbuf *b = NULL; 2323 struct sshcomp *comp; 2324 struct sshenc *enc; 2325 struct sshmac *mac; 2326 struct newkeys *newkey = NULL; 2327 size_t keylen, ivlen, maclen; 2328 int r; 2329 2330 if ((newkey = calloc(1, sizeof(*newkey))) == NULL) { 2331 r = SSH_ERR_ALLOC_FAIL; 2332 goto out; 2333 } 2334 if ((r = sshbuf_froms(m, &b)) != 0) 2335 goto out; 2336 #ifdef DEBUG_PK 2337 sshbuf_dump(b, stderr); 2338 #endif 2339 enc = &newkey->enc; 2340 mac = &newkey->mac; 2341 comp = &newkey->comp; 2342 2343 if ((r = sshbuf_get_cstring(b, &enc->name, NULL)) != 0 || 2344 (r = sshbuf_get_u32(b, (u_int *)&enc->enabled)) != 0 || 2345 (r = sshbuf_get_u32(b, &enc->block_size)) != 0 || 2346 (r = sshbuf_get_string(b, &enc->key, &keylen)) != 0 || 2347 (r = sshbuf_get_string(b, &enc->iv, &ivlen)) != 0) 2348 goto out; 2349 if ((enc->cipher = cipher_by_name(enc->name)) == NULL) { 2350 r = SSH_ERR_INVALID_FORMAT; 2351 goto out; 2352 } 2353 if (cipher_authlen(enc->cipher) == 0) { 2354 if ((r = sshbuf_get_cstring(b, &mac->name, NULL)) != 0) 2355 goto out; 2356 if ((r = mac_setup(mac, mac->name)) != 0) 2357 goto out; 2358 if ((r = sshbuf_get_u32(b, (u_int *)&mac->enabled)) != 0 || 2359 (r = sshbuf_get_string(b, &mac->key, &maclen)) != 0) 2360 goto out; 2361 if (maclen > mac->key_len) { 2362 r = SSH_ERR_INVALID_FORMAT; 2363 goto out; 2364 } 2365 mac->key_len = maclen; 2366 } 2367 if ((r = sshbuf_get_u32(b, &comp->type)) != 0 || 2368 (r = sshbuf_get_cstring(b, &comp->name, NULL)) != 0) 2369 goto out; 2370 if (sshbuf_len(b) != 0) { 2371 r = SSH_ERR_INVALID_FORMAT; 2372 goto out; 2373 } 2374 enc->key_len = keylen; 2375 enc->iv_len = ivlen; 2376 ssh->kex->newkeys[mode] = newkey; 2377 newkey = NULL; 2378 r = 0; 2379 out: 2380 free(newkey); 2381 sshbuf_free(b); 2382 return r; 2383 } 2384 2385 /* restore kex from blob for packet state de-serialization */ 2386 static int 2387 kex_from_blob(struct sshbuf *m, struct kex **kexp) 2388 { 2389 struct kex *kex; 2390 int r; 2391 2392 if ((kex = kex_new()) == NULL) 2393 return SSH_ERR_ALLOC_FAIL; 2394 if ((r = sshbuf_get_string(m, &kex->session_id, &kex->session_id_len)) != 0 || 2395 (r = sshbuf_get_u32(m, &kex->we_need)) != 0 || 2396 (r = sshbuf_get_cstring(m, &kex->hostkey_alg, NULL)) != 0 || 2397 (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_type)) != 0 || 2398 (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_nid)) != 0 || 2399 (r = sshbuf_get_u32(m, &kex->kex_type)) != 0 || 2400 (r = sshbuf_get_stringb(m, kex->my)) != 0 || 2401 (r = sshbuf_get_stringb(m, kex->peer)) != 0 || 2402 (r = sshbuf_get_stringb(m, kex->client_version)) != 0 || 2403 (r = sshbuf_get_stringb(m, kex->server_version)) != 0 || 2404 (r = sshbuf_get_u32(m, &kex->flags)) != 0) 2405 goto out; 2406 kex->server = 1; 2407 kex->done = 1; 2408 r = 0; 2409 out: 2410 if (r != 0 || kexp == NULL) { 2411 kex_free(kex); 2412 if (kexp != NULL) 2413 *kexp = NULL; 2414 } else { 2415 kex_free(*kexp); 2416 *kexp = kex; 2417 } 2418 return r; 2419 } 2420 2421 /* 2422 * Restore packet state from content of blob 'm' (de-serialization). 2423 * Note that 'm' will be partially consumed on parsing or any other errors. 2424 */ 2425 int 2426 ssh_packet_set_state(struct ssh *ssh, struct sshbuf *m) 2427 { 2428 struct session_state *state = ssh->state; 2429 const u_char *input, *output; 2430 size_t ilen, olen; 2431 int r; 2432 2433 if ((r = kex_from_blob(m, &ssh->kex)) != 0 || 2434 (r = newkeys_from_blob(m, ssh, MODE_OUT)) != 0 || 2435 (r = newkeys_from_blob(m, ssh, MODE_IN)) != 0 || 2436 (r = sshbuf_get_u64(m, &state->rekey_limit)) != 0 || 2437 (r = sshbuf_get_u32(m, &state->rekey_interval)) != 0 || 2438 (r = sshbuf_get_u32(m, &state->p_send.seqnr)) != 0 || 2439 (r = sshbuf_get_u64(m, &state->p_send.blocks)) != 0 || 2440 (r = sshbuf_get_u32(m, &state->p_send.packets)) != 0 || 2441 (r = sshbuf_get_u64(m, &state->p_send.bytes)) != 0 || 2442 (r = sshbuf_get_u32(m, &state->p_read.seqnr)) != 0 || 2443 (r = sshbuf_get_u64(m, &state->p_read.blocks)) != 0 || 2444 (r = sshbuf_get_u32(m, &state->p_read.packets)) != 0 || 2445 (r = sshbuf_get_u64(m, &state->p_read.bytes)) != 0) 2446 return r; 2447 /* 2448 * We set the time here so that in post-auth privsep slave we 2449 * count from the completion of the authentication. 2450 */ 2451 state->rekey_time = monotime(); 2452 /* XXX ssh_set_newkeys overrides p_read.packets? XXX */ 2453 if ((r = ssh_set_newkeys(ssh, MODE_IN)) != 0 || 2454 (r = ssh_set_newkeys(ssh, MODE_OUT)) != 0) 2455 return r; 2456 2457 if ((r = ssh_packet_set_postauth(ssh)) != 0) 2458 return r; 2459 2460 sshbuf_reset(state->input); 2461 sshbuf_reset(state->output); 2462 if ((r = sshbuf_get_string_direct(m, &input, &ilen)) != 0 || 2463 (r = sshbuf_get_string_direct(m, &output, &olen)) != 0 || 2464 (r = sshbuf_put(state->input, input, ilen)) != 0 || 2465 (r = sshbuf_put(state->output, output, olen)) != 0) 2466 return r; 2467 2468 if (sshbuf_len(m)) 2469 return SSH_ERR_INVALID_FORMAT; 2470 debug3("%s: done", __func__); 2471 return 0; 2472 } 2473 2474 /* NEW API */ 2475 2476 /* put data to the outgoing packet */ 2477 2478 int 2479 sshpkt_put(struct ssh *ssh, const void *v, size_t len) 2480 { 2481 return sshbuf_put(ssh->state->outgoing_packet, v, len); 2482 } 2483 2484 int 2485 sshpkt_putb(struct ssh *ssh, const struct sshbuf *b) 2486 { 2487 return sshbuf_putb(ssh->state->outgoing_packet, b); 2488 } 2489 2490 int 2491 sshpkt_put_u8(struct ssh *ssh, u_char val) 2492 { 2493 return sshbuf_put_u8(ssh->state->outgoing_packet, val); 2494 } 2495 2496 int 2497 sshpkt_put_u32(struct ssh *ssh, u_int32_t val) 2498 { 2499 return sshbuf_put_u32(ssh->state->outgoing_packet, val); 2500 } 2501 2502 int 2503 sshpkt_put_u64(struct ssh *ssh, u_int64_t val) 2504 { 2505 return sshbuf_put_u64(ssh->state->outgoing_packet, val); 2506 } 2507 2508 int 2509 sshpkt_put_string(struct ssh *ssh, const void *v, size_t len) 2510 { 2511 return sshbuf_put_string(ssh->state->outgoing_packet, v, len); 2512 } 2513 2514 int 2515 sshpkt_put_cstring(struct ssh *ssh, const void *v) 2516 { 2517 return sshbuf_put_cstring(ssh->state->outgoing_packet, v); 2518 } 2519 2520 int 2521 sshpkt_put_stringb(struct ssh *ssh, const struct sshbuf *v) 2522 { 2523 return sshbuf_put_stringb(ssh->state->outgoing_packet, v); 2524 } 2525 2526 int 2527 sshpkt_getb_froms(struct ssh *ssh, struct sshbuf **valp) 2528 { 2529 return sshbuf_froms(ssh->state->incoming_packet, valp); 2530 } 2531 2532 #ifdef WITH_OPENSSL 2533 #ifdef OPENSSL_HAS_ECC 2534 int 2535 sshpkt_put_ec(struct ssh *ssh, const EC_POINT *v, const EC_GROUP *g) 2536 { 2537 return sshbuf_put_ec(ssh->state->outgoing_packet, v, g); 2538 } 2539 #endif /* OPENSSL_HAS_ECC */ 2540 2541 2542 int 2543 sshpkt_put_bignum2(struct ssh *ssh, const BIGNUM *v) 2544 { 2545 return sshbuf_put_bignum2(ssh->state->outgoing_packet, v); 2546 } 2547 #endif /* WITH_OPENSSL */ 2548 2549 /* fetch data from the incoming packet */ 2550 2551 int 2552 sshpkt_get(struct ssh *ssh, void *valp, size_t len) 2553 { 2554 return sshbuf_get(ssh->state->incoming_packet, valp, len); 2555 } 2556 2557 int 2558 sshpkt_get_u8(struct ssh *ssh, u_char *valp) 2559 { 2560 return sshbuf_get_u8(ssh->state->incoming_packet, valp); 2561 } 2562 2563 int 2564 sshpkt_get_u32(struct ssh *ssh, u_int32_t *valp) 2565 { 2566 return sshbuf_get_u32(ssh->state->incoming_packet, valp); 2567 } 2568 2569 int 2570 sshpkt_get_u64(struct ssh *ssh, u_int64_t *valp) 2571 { 2572 return sshbuf_get_u64(ssh->state->incoming_packet, valp); 2573 } 2574 2575 int 2576 sshpkt_get_string(struct ssh *ssh, u_char **valp, size_t *lenp) 2577 { 2578 return sshbuf_get_string(ssh->state->incoming_packet, valp, lenp); 2579 } 2580 2581 int 2582 sshpkt_get_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp) 2583 { 2584 return sshbuf_get_string_direct(ssh->state->incoming_packet, valp, lenp); 2585 } 2586 2587 int 2588 sshpkt_peek_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp) 2589 { 2590 return sshbuf_peek_string_direct(ssh->state->incoming_packet, valp, lenp); 2591 } 2592 2593 int 2594 sshpkt_get_cstring(struct ssh *ssh, char **valp, size_t *lenp) 2595 { 2596 return sshbuf_get_cstring(ssh->state->incoming_packet, valp, lenp); 2597 } 2598 2599 #ifdef WITH_OPENSSL 2600 #ifdef OPENSSL_HAS_ECC 2601 int 2602 sshpkt_get_ec(struct ssh *ssh, EC_POINT *v, const EC_GROUP *g) 2603 { 2604 return sshbuf_get_ec(ssh->state->incoming_packet, v, g); 2605 } 2606 #endif /* OPENSSL_HAS_ECC */ 2607 2608 int 2609 sshpkt_get_bignum2(struct ssh *ssh, BIGNUM **valp) 2610 { 2611 return sshbuf_get_bignum2(ssh->state->incoming_packet, valp); 2612 } 2613 #endif /* WITH_OPENSSL */ 2614 2615 int 2616 sshpkt_get_end(struct ssh *ssh) 2617 { 2618 if (sshbuf_len(ssh->state->incoming_packet) > 0) 2619 return SSH_ERR_UNEXPECTED_TRAILING_DATA; 2620 return 0; 2621 } 2622 2623 const u_char * 2624 sshpkt_ptr(struct ssh *ssh, size_t *lenp) 2625 { 2626 if (lenp != NULL) 2627 *lenp = sshbuf_len(ssh->state->incoming_packet); 2628 return sshbuf_ptr(ssh->state->incoming_packet); 2629 } 2630 2631 /* start a new packet */ 2632 2633 int 2634 sshpkt_start(struct ssh *ssh, u_char type) 2635 { 2636 u_char buf[6]; /* u32 packet length, u8 pad len, u8 type */ 2637 2638 DBG(debug("packet_start[%d]", type)); 2639 memset(buf, 0, sizeof(buf)); 2640 buf[sizeof(buf) - 1] = type; 2641 sshbuf_reset(ssh->state->outgoing_packet); 2642 return sshbuf_put(ssh->state->outgoing_packet, buf, sizeof(buf)); 2643 } 2644 2645 static int 2646 ssh_packet_send_mux(struct ssh *ssh) 2647 { 2648 struct session_state *state = ssh->state; 2649 u_char type, *cp; 2650 size_t len; 2651 int r; 2652 2653 if (ssh->kex) 2654 return SSH_ERR_INTERNAL_ERROR; 2655 len = sshbuf_len(state->outgoing_packet); 2656 if (len < 6) 2657 return SSH_ERR_INTERNAL_ERROR; 2658 cp = sshbuf_mutable_ptr(state->outgoing_packet); 2659 type = cp[5]; 2660 if (ssh_packet_log_type(type)) 2661 debug3("%s: type %u", __func__, type); 2662 /* drop everything, but the connection protocol */ 2663 if (type >= SSH2_MSG_CONNECTION_MIN && 2664 type <= SSH2_MSG_CONNECTION_MAX) { 2665 POKE_U32(cp, len - 4); 2666 if ((r = sshbuf_putb(state->output, 2667 state->outgoing_packet)) != 0) 2668 return r; 2669 /* sshbuf_dump(state->output, stderr); */ 2670 } 2671 sshbuf_reset(state->outgoing_packet); 2672 return 0; 2673 } 2674 2675 /* 2676 * 9.2. Ignored Data Message 2677 * 2678 * byte SSH_MSG_IGNORE 2679 * string data 2680 * 2681 * All implementations MUST understand (and ignore) this message at any 2682 * time (after receiving the protocol version). No implementation is 2683 * required to send them. This message can be used as an additional 2684 * protection measure against advanced traffic analysis techniques. 2685 */ 2686 int 2687 sshpkt_msg_ignore(struct ssh *ssh, u_int nbytes) 2688 { 2689 u_int32_t rnd = 0; 2690 int r; 2691 u_int i; 2692 2693 if ((r = sshpkt_start(ssh, SSH2_MSG_IGNORE)) != 0 || 2694 (r = sshpkt_put_u32(ssh, nbytes)) != 0) 2695 return r; 2696 for (i = 0; i < nbytes; i++) { 2697 if (i % 4 == 0) 2698 rnd = arc4random(); 2699 if ((r = sshpkt_put_u8(ssh, (u_char)rnd & 0xff)) != 0) 2700 return r; 2701 rnd >>= 8; 2702 } 2703 return 0; 2704 } 2705 2706 /* send it */ 2707 2708 int 2709 sshpkt_send(struct ssh *ssh) 2710 { 2711 if (ssh->state && ssh->state->mux) 2712 return ssh_packet_send_mux(ssh); 2713 return ssh_packet_send2(ssh); 2714 } 2715 2716 int 2717 sshpkt_disconnect(struct ssh *ssh, const char *fmt,...) 2718 { 2719 char buf[1024]; 2720 va_list args; 2721 int r; 2722 2723 va_start(args, fmt); 2724 vsnprintf(buf, sizeof(buf), fmt, args); 2725 va_end(args); 2726 2727 if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 || 2728 (r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_PROTOCOL_ERROR)) != 0 || 2729 (r = sshpkt_put_cstring(ssh, buf)) != 0 || 2730 (r = sshpkt_put_cstring(ssh, "")) != 0 || 2731 (r = sshpkt_send(ssh)) != 0) 2732 return r; 2733 return 0; 2734 } 2735 2736 /* roundup current message to pad bytes */ 2737 int 2738 sshpkt_add_padding(struct ssh *ssh, u_char pad) 2739 { 2740 ssh->state->extra_pad = pad; 2741 return 0; 2742 } 2743