1 /* $OpenBSD: packet.c,v 1.317 2024/08/23 04:51:00 deraadt 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 <sys/types.h> 41 #include <sys/queue.h> 42 #include <sys/socket.h> 43 #include <sys/time.h> 44 #include <netinet/in.h> 45 #include <netinet/ip.h> 46 47 #include <errno.h> 48 #include <netdb.h> 49 #include <stdarg.h> 50 #include <stdio.h> 51 #include <stdlib.h> 52 #include <string.h> 53 #include <unistd.h> 54 #include <limits.h> 55 #include <poll.h> 56 #include <signal.h> 57 #include <time.h> 58 59 #ifdef WITH_ZLIB 60 #include <zlib.h> 61 #endif 62 63 #include "xmalloc.h" 64 #include "compat.h" 65 #include "ssh2.h" 66 #include "cipher.h" 67 #include "sshkey.h" 68 #include "kex.h" 69 #include "digest.h" 70 #include "mac.h" 71 #include "log.h" 72 #include "canohost.h" 73 #include "misc.h" 74 #include "channels.h" 75 #include "ssh.h" 76 #include "packet.h" 77 #include "ssherr.h" 78 #include "sshbuf.h" 79 80 #ifdef PACKET_DEBUG 81 #define DBG(x) x 82 #else 83 #define DBG(x) 84 #endif 85 86 #define PACKET_MAX_SIZE (256 * 1024) 87 88 struct packet_state { 89 u_int32_t seqnr; 90 u_int32_t packets; 91 u_int64_t blocks; 92 u_int64_t bytes; 93 }; 94 95 struct packet { 96 TAILQ_ENTRY(packet) next; 97 u_char type; 98 struct sshbuf *payload; 99 }; 100 101 struct session_state { 102 /* 103 * This variable contains the file descriptors used for 104 * communicating with the other side. connection_in is used for 105 * reading; connection_out for writing. These can be the same 106 * descriptor, in which case it is assumed to be a socket. 107 */ 108 int connection_in; 109 int connection_out; 110 111 /* Protocol flags for the remote side. */ 112 u_int remote_protocol_flags; 113 114 /* Encryption context for receiving data. Only used for decryption. */ 115 struct sshcipher_ctx *receive_context; 116 117 /* Encryption context for sending data. Only used for encryption. */ 118 struct sshcipher_ctx *send_context; 119 120 /* Buffer for raw input data from the socket. */ 121 struct sshbuf *input; 122 123 /* Buffer for raw output data going to the socket. */ 124 struct sshbuf *output; 125 126 /* Buffer for the partial outgoing packet being constructed. */ 127 struct sshbuf *outgoing_packet; 128 129 /* Buffer for the incoming packet currently being processed. */ 130 struct sshbuf *incoming_packet; 131 132 /* Scratch buffer for packet compression/decompression. */ 133 struct sshbuf *compression_buffer; 134 135 #ifdef WITH_ZLIB 136 /* Incoming/outgoing compression dictionaries */ 137 z_stream compression_in_stream; 138 z_stream compression_out_stream; 139 #endif 140 int compression_in_started; 141 int compression_out_started; 142 int compression_in_failures; 143 int compression_out_failures; 144 145 /* default maximum packet size */ 146 u_int max_packet_size; 147 148 /* Flag indicating whether this module has been initialized. */ 149 int initialized; 150 151 /* Set to true if the connection is interactive. */ 152 int interactive_mode; 153 154 /* Set to true if we are the server side. */ 155 int server_side; 156 157 /* Set to true if we are authenticated. */ 158 int after_authentication; 159 160 int keep_alive_timeouts; 161 162 /* The maximum time that we will wait to send or receive a packet */ 163 int packet_timeout_ms; 164 165 /* Session key information for Encryption and MAC */ 166 struct newkeys *newkeys[MODE_MAX]; 167 struct packet_state p_read, p_send; 168 169 /* Volume-based rekeying */ 170 u_int64_t max_blocks_in, max_blocks_out, rekey_limit; 171 172 /* Time-based rekeying */ 173 u_int32_t rekey_interval; /* how often in seconds */ 174 time_t rekey_time; /* time of last rekeying */ 175 176 /* roundup current message to extra_pad bytes */ 177 u_char extra_pad; 178 179 /* XXX discard incoming data after MAC error */ 180 u_int packet_discard; 181 size_t packet_discard_mac_already; 182 struct sshmac *packet_discard_mac; 183 184 /* Used in packet_read_poll2() */ 185 u_int packlen; 186 187 /* Used in packet_send2 */ 188 int rekeying; 189 190 /* Used in ssh_packet_send_mux() */ 191 int mux; 192 193 /* Used in packet_set_interactive */ 194 int set_interactive_called; 195 196 /* Used in packet_set_maxsize */ 197 int set_maxsize_called; 198 199 /* One-off warning about weak ciphers */ 200 int cipher_warning_done; 201 202 /* Hook for fuzzing inbound packets */ 203 ssh_packet_hook_fn *hook_in; 204 void *hook_in_ctx; 205 206 TAILQ_HEAD(, packet) outgoing; 207 }; 208 209 struct ssh * 210 ssh_alloc_session_state(void) 211 { 212 struct ssh *ssh = NULL; 213 struct session_state *state = NULL; 214 215 if ((ssh = calloc(1, sizeof(*ssh))) == NULL || 216 (state = calloc(1, sizeof(*state))) == NULL || 217 (ssh->kex = kex_new()) == NULL || 218 (state->input = sshbuf_new()) == NULL || 219 (state->output = sshbuf_new()) == NULL || 220 (state->outgoing_packet = sshbuf_new()) == NULL || 221 (state->incoming_packet = sshbuf_new()) == NULL) 222 goto fail; 223 TAILQ_INIT(&state->outgoing); 224 TAILQ_INIT(&ssh->private_keys); 225 TAILQ_INIT(&ssh->public_keys); 226 state->connection_in = -1; 227 state->connection_out = -1; 228 state->max_packet_size = 32768; 229 state->packet_timeout_ms = -1; 230 state->p_send.packets = state->p_read.packets = 0; 231 state->initialized = 1; 232 /* 233 * ssh_packet_send2() needs to queue packets until 234 * we've done the initial key exchange. 235 */ 236 state->rekeying = 1; 237 ssh->state = state; 238 return ssh; 239 fail: 240 if (ssh) { 241 kex_free(ssh->kex); 242 free(ssh); 243 } 244 if (state) { 245 sshbuf_free(state->input); 246 sshbuf_free(state->output); 247 sshbuf_free(state->incoming_packet); 248 sshbuf_free(state->outgoing_packet); 249 free(state); 250 } 251 return NULL; 252 } 253 254 void 255 ssh_packet_set_input_hook(struct ssh *ssh, ssh_packet_hook_fn *hook, void *ctx) 256 { 257 ssh->state->hook_in = hook; 258 ssh->state->hook_in_ctx = ctx; 259 } 260 261 /* Returns nonzero if rekeying is in progress */ 262 int 263 ssh_packet_is_rekeying(struct ssh *ssh) 264 { 265 return ssh->state->rekeying || 266 (ssh->kex != NULL && ssh->kex->done == 0); 267 } 268 269 /* 270 * Sets the descriptors used for communication. 271 */ 272 struct ssh * 273 ssh_packet_set_connection(struct ssh *ssh, int fd_in, int fd_out) 274 { 275 struct session_state *state; 276 const struct sshcipher *none = cipher_by_name("none"); 277 int r; 278 279 if (none == NULL) { 280 error_f("cannot load cipher 'none'"); 281 return NULL; 282 } 283 if (ssh == NULL) 284 ssh = ssh_alloc_session_state(); 285 if (ssh == NULL) { 286 error_f("could not allocate state"); 287 return NULL; 288 } 289 state = ssh->state; 290 state->connection_in = fd_in; 291 state->connection_out = fd_out; 292 if ((r = cipher_init(&state->send_context, none, 293 (const u_char *)"", 0, NULL, 0, CIPHER_ENCRYPT)) != 0 || 294 (r = cipher_init(&state->receive_context, none, 295 (const u_char *)"", 0, NULL, 0, CIPHER_DECRYPT)) != 0) { 296 error_fr(r, "cipher_init failed"); 297 free(ssh); /* XXX need ssh_free_session_state? */ 298 return NULL; 299 } 300 state->newkeys[MODE_IN] = state->newkeys[MODE_OUT] = NULL; 301 /* 302 * Cache the IP address of the remote connection for use in error 303 * messages that might be generated after the connection has closed. 304 */ 305 (void)ssh_remote_ipaddr(ssh); 306 return ssh; 307 } 308 309 void 310 ssh_packet_set_timeout(struct ssh *ssh, int timeout, int count) 311 { 312 struct session_state *state = ssh->state; 313 314 if (timeout <= 0 || count <= 0) { 315 state->packet_timeout_ms = -1; 316 return; 317 } 318 if ((INT_MAX / 1000) / count < timeout) 319 state->packet_timeout_ms = INT_MAX; 320 else 321 state->packet_timeout_ms = timeout * count * 1000; 322 } 323 324 void 325 ssh_packet_set_mux(struct ssh *ssh) 326 { 327 ssh->state->mux = 1; 328 ssh->state->rekeying = 0; 329 kex_free(ssh->kex); 330 ssh->kex = NULL; 331 } 332 333 int 334 ssh_packet_get_mux(struct ssh *ssh) 335 { 336 return ssh->state->mux; 337 } 338 339 int 340 ssh_packet_set_log_preamble(struct ssh *ssh, const char *fmt, ...) 341 { 342 va_list args; 343 int r; 344 345 free(ssh->log_preamble); 346 if (fmt == NULL) 347 ssh->log_preamble = NULL; 348 else { 349 va_start(args, fmt); 350 r = vasprintf(&ssh->log_preamble, fmt, args); 351 va_end(args); 352 if (r < 0 || ssh->log_preamble == NULL) 353 return SSH_ERR_ALLOC_FAIL; 354 } 355 return 0; 356 } 357 358 int 359 ssh_packet_stop_discard(struct ssh *ssh) 360 { 361 struct session_state *state = ssh->state; 362 int r; 363 364 if (state->packet_discard_mac) { 365 char buf[1024]; 366 size_t dlen = PACKET_MAX_SIZE; 367 368 if (dlen > state->packet_discard_mac_already) 369 dlen -= state->packet_discard_mac_already; 370 memset(buf, 'a', sizeof(buf)); 371 while (sshbuf_len(state->incoming_packet) < dlen) 372 if ((r = sshbuf_put(state->incoming_packet, buf, 373 sizeof(buf))) != 0) 374 return r; 375 (void) mac_compute(state->packet_discard_mac, 376 state->p_read.seqnr, 377 sshbuf_ptr(state->incoming_packet), dlen, 378 NULL, 0); 379 } 380 logit("Finished discarding for %.200s port %d", 381 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 382 return SSH_ERR_MAC_INVALID; 383 } 384 385 static int 386 ssh_packet_start_discard(struct ssh *ssh, struct sshenc *enc, 387 struct sshmac *mac, size_t mac_already, u_int discard) 388 { 389 struct session_state *state = ssh->state; 390 int r; 391 392 if (enc == NULL || !cipher_is_cbc(enc->cipher) || (mac && mac->etm)) { 393 if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0) 394 return r; 395 return SSH_ERR_MAC_INVALID; 396 } 397 /* 398 * Record number of bytes over which the mac has already 399 * been computed in order to minimize timing attacks. 400 */ 401 if (mac && mac->enabled) { 402 state->packet_discard_mac = mac; 403 state->packet_discard_mac_already = mac_already; 404 } 405 if (sshbuf_len(state->input) >= discard) 406 return ssh_packet_stop_discard(ssh); 407 state->packet_discard = discard - sshbuf_len(state->input); 408 return 0; 409 } 410 411 /* Returns 1 if remote host is connected via socket, 0 if not. */ 412 413 int 414 ssh_packet_connection_is_on_socket(struct ssh *ssh) 415 { 416 struct session_state *state; 417 struct sockaddr_storage from, to; 418 socklen_t fromlen, tolen; 419 420 if (ssh == NULL || ssh->state == NULL) 421 return 0; 422 423 state = ssh->state; 424 if (state->connection_in == -1 || state->connection_out == -1) 425 return 0; 426 /* filedescriptors in and out are the same, so it's a socket */ 427 if (state->connection_in == state->connection_out) 428 return 1; 429 fromlen = sizeof(from); 430 memset(&from, 0, sizeof(from)); 431 if (getpeername(state->connection_in, (struct sockaddr *)&from, 432 &fromlen) == -1) 433 return 0; 434 tolen = sizeof(to); 435 memset(&to, 0, sizeof(to)); 436 if (getpeername(state->connection_out, (struct sockaddr *)&to, 437 &tolen) == -1) 438 return 0; 439 if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0) 440 return 0; 441 if (from.ss_family != AF_INET && from.ss_family != AF_INET6) 442 return 0; 443 return 1; 444 } 445 446 void 447 ssh_packet_get_bytes(struct ssh *ssh, u_int64_t *ibytes, u_int64_t *obytes) 448 { 449 if (ibytes) 450 *ibytes = ssh->state->p_read.bytes; 451 if (obytes) 452 *obytes = ssh->state->p_send.bytes; 453 } 454 455 int 456 ssh_packet_connection_af(struct ssh *ssh) 457 { 458 return get_sock_af(ssh->state->connection_out); 459 } 460 461 /* Sets the connection into non-blocking mode. */ 462 463 void 464 ssh_packet_set_nonblocking(struct ssh *ssh) 465 { 466 /* Set the socket into non-blocking mode. */ 467 set_nonblock(ssh->state->connection_in); 468 469 if (ssh->state->connection_out != ssh->state->connection_in) 470 set_nonblock(ssh->state->connection_out); 471 } 472 473 /* Returns the socket used for reading. */ 474 475 int 476 ssh_packet_get_connection_in(struct ssh *ssh) 477 { 478 return ssh->state->connection_in; 479 } 480 481 /* Returns the descriptor used for writing. */ 482 483 int 484 ssh_packet_get_connection_out(struct ssh *ssh) 485 { 486 return ssh->state->connection_out; 487 } 488 489 /* 490 * Returns the IP-address of the remote host as a string. The returned 491 * string must not be freed. 492 */ 493 494 const char * 495 ssh_remote_ipaddr(struct ssh *ssh) 496 { 497 int sock; 498 499 /* Check whether we have cached the ipaddr. */ 500 if (ssh->remote_ipaddr == NULL) { 501 if (ssh_packet_connection_is_on_socket(ssh)) { 502 sock = ssh->state->connection_in; 503 ssh->remote_ipaddr = get_peer_ipaddr(sock); 504 ssh->remote_port = get_peer_port(sock); 505 ssh->local_ipaddr = get_local_ipaddr(sock); 506 ssh->local_port = get_local_port(sock); 507 } else { 508 ssh->remote_ipaddr = xstrdup("UNKNOWN"); 509 ssh->remote_port = 65535; 510 ssh->local_ipaddr = xstrdup("UNKNOWN"); 511 ssh->local_port = 65535; 512 } 513 } 514 return ssh->remote_ipaddr; 515 } 516 517 /* 518 * Returns the remote DNS hostname as a string. The returned string must not 519 * be freed. NB. this will usually trigger a DNS query. Return value is on 520 * heap and no caching is performed. 521 * This function does additional checks on the hostname to mitigate some 522 * attacks based on conflation of hostnames and addresses and will 523 * fall back to returning an address on error. 524 */ 525 526 char * 527 ssh_remote_hostname(struct ssh *ssh) 528 { 529 struct sockaddr_storage from; 530 socklen_t fromlen; 531 struct addrinfo hints, *ai, *aitop; 532 char name[NI_MAXHOST], ntop2[NI_MAXHOST]; 533 const char *ntop = ssh_remote_ipaddr(ssh); 534 535 /* Get IP address of client. */ 536 fromlen = sizeof(from); 537 memset(&from, 0, sizeof(from)); 538 if (getpeername(ssh_packet_get_connection_in(ssh), 539 (struct sockaddr *)&from, &fromlen) == -1) { 540 debug_f("getpeername failed: %.100s", strerror(errno)); 541 return xstrdup(ntop); 542 } 543 544 debug3_f("trying to reverse map address %.100s.", ntop); 545 /* Map the IP address to a host name. */ 546 if (getnameinfo((struct sockaddr *)&from, fromlen, name, sizeof(name), 547 NULL, 0, NI_NAMEREQD) != 0) { 548 /* Host name not found. Use ip address. */ 549 return xstrdup(ntop); 550 } 551 552 /* 553 * if reverse lookup result looks like a numeric hostname, 554 * someone is trying to trick us by PTR record like following: 555 * 1.1.1.10.in-addr.arpa. IN PTR 2.3.4.5 556 */ 557 memset(&hints, 0, sizeof(hints)); 558 hints.ai_socktype = SOCK_DGRAM; /*dummy*/ 559 hints.ai_flags = AI_NUMERICHOST; 560 if (getaddrinfo(name, NULL, &hints, &ai) == 0) { 561 logit("Nasty PTR record \"%s\" is set up for %s, ignoring", 562 name, ntop); 563 freeaddrinfo(ai); 564 return xstrdup(ntop); 565 } 566 567 /* Names are stored in lowercase. */ 568 lowercase(name); 569 570 /* 571 * Map it back to an IP address and check that the given 572 * address actually is an address of this host. This is 573 * necessary because anyone with access to a name server can 574 * define arbitrary names for an IP address. Mapping from 575 * name to IP address can be trusted better (but can still be 576 * fooled if the intruder has access to the name server of 577 * the domain). 578 */ 579 memset(&hints, 0, sizeof(hints)); 580 hints.ai_family = from.ss_family; 581 hints.ai_socktype = SOCK_STREAM; 582 if (getaddrinfo(name, NULL, &hints, &aitop) != 0) { 583 logit("reverse mapping checking getaddrinfo for %.700s " 584 "[%s] failed.", name, ntop); 585 return xstrdup(ntop); 586 } 587 /* Look for the address from the list of addresses. */ 588 for (ai = aitop; ai; ai = ai->ai_next) { 589 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop2, 590 sizeof(ntop2), NULL, 0, NI_NUMERICHOST) == 0 && 591 (strcmp(ntop, ntop2) == 0)) 592 break; 593 } 594 freeaddrinfo(aitop); 595 /* If we reached the end of the list, the address was not there. */ 596 if (ai == NULL) { 597 /* Address not found for the host name. */ 598 logit("Address %.100s maps to %.600s, but this does not " 599 "map back to the address.", ntop, name); 600 return xstrdup(ntop); 601 } 602 return xstrdup(name); 603 } 604 605 /* Returns the port number of the remote host. */ 606 607 int 608 ssh_remote_port(struct ssh *ssh) 609 { 610 (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */ 611 return ssh->remote_port; 612 } 613 614 /* 615 * Returns the IP-address of the local host as a string. The returned 616 * string must not be freed. 617 */ 618 619 const char * 620 ssh_local_ipaddr(struct ssh *ssh) 621 { 622 (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */ 623 return ssh->local_ipaddr; 624 } 625 626 /* Returns the port number of the local host. */ 627 628 int 629 ssh_local_port(struct ssh *ssh) 630 { 631 (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */ 632 return ssh->local_port; 633 } 634 635 /* Returns the routing domain of the input socket, or NULL if unavailable */ 636 const char * 637 ssh_packet_rdomain_in(struct ssh *ssh) 638 { 639 if (ssh->rdomain_in != NULL) 640 return ssh->rdomain_in; 641 if (!ssh_packet_connection_is_on_socket(ssh)) 642 return NULL; 643 ssh->rdomain_in = get_rdomain(ssh->state->connection_in); 644 return ssh->rdomain_in; 645 } 646 647 /* Closes the connection and clears and frees internal data structures. */ 648 649 static void 650 ssh_packet_close_internal(struct ssh *ssh, int do_close) 651 { 652 struct session_state *state = ssh->state; 653 u_int mode; 654 655 if (!state->initialized) 656 return; 657 state->initialized = 0; 658 if (do_close) { 659 if (state->connection_in == state->connection_out) { 660 close(state->connection_out); 661 } else { 662 close(state->connection_in); 663 close(state->connection_out); 664 } 665 } 666 sshbuf_free(state->input); 667 sshbuf_free(state->output); 668 sshbuf_free(state->outgoing_packet); 669 sshbuf_free(state->incoming_packet); 670 for (mode = 0; mode < MODE_MAX; mode++) { 671 kex_free_newkeys(state->newkeys[mode]); /* current keys */ 672 state->newkeys[mode] = NULL; 673 ssh_clear_newkeys(ssh, mode); /* next keys */ 674 } 675 #ifdef WITH_ZLIB 676 /* compression state is in shared mem, so we can only release it once */ 677 if (do_close && state->compression_buffer) { 678 sshbuf_free(state->compression_buffer); 679 if (state->compression_out_started) { 680 z_streamp stream = &state->compression_out_stream; 681 debug("compress outgoing: " 682 "raw data %llu, compressed %llu, factor %.2f", 683 (unsigned long long)stream->total_in, 684 (unsigned long long)stream->total_out, 685 stream->total_in == 0 ? 0.0 : 686 (double) stream->total_out / stream->total_in); 687 if (state->compression_out_failures == 0) 688 deflateEnd(stream); 689 } 690 if (state->compression_in_started) { 691 z_streamp stream = &state->compression_in_stream; 692 debug("compress incoming: " 693 "raw data %llu, compressed %llu, factor %.2f", 694 (unsigned long long)stream->total_out, 695 (unsigned long long)stream->total_in, 696 stream->total_out == 0 ? 0.0 : 697 (double) stream->total_in / stream->total_out); 698 if (state->compression_in_failures == 0) 699 inflateEnd(stream); 700 } 701 } 702 #endif /* WITH_ZLIB */ 703 cipher_free(state->send_context); 704 cipher_free(state->receive_context); 705 state->send_context = state->receive_context = NULL; 706 if (do_close) { 707 free(ssh->local_ipaddr); 708 ssh->local_ipaddr = NULL; 709 free(ssh->remote_ipaddr); 710 ssh->remote_ipaddr = NULL; 711 free(ssh->state); 712 ssh->state = NULL; 713 kex_free(ssh->kex); 714 ssh->kex = NULL; 715 } 716 } 717 718 void 719 ssh_packet_close(struct ssh *ssh) 720 { 721 ssh_packet_close_internal(ssh, 1); 722 } 723 724 void 725 ssh_packet_clear_keys(struct ssh *ssh) 726 { 727 ssh_packet_close_internal(ssh, 0); 728 } 729 730 /* Sets remote side protocol flags. */ 731 732 void 733 ssh_packet_set_protocol_flags(struct ssh *ssh, u_int protocol_flags) 734 { 735 ssh->state->remote_protocol_flags = protocol_flags; 736 } 737 738 /* Returns the remote protocol flags set earlier by the above function. */ 739 740 u_int 741 ssh_packet_get_protocol_flags(struct ssh *ssh) 742 { 743 return ssh->state->remote_protocol_flags; 744 } 745 746 /* 747 * Starts packet compression from the next packet on in both directions. 748 * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip. 749 */ 750 751 static int 752 ssh_packet_init_compression(struct ssh *ssh) 753 { 754 if (!ssh->state->compression_buffer && 755 ((ssh->state->compression_buffer = sshbuf_new()) == NULL)) 756 return SSH_ERR_ALLOC_FAIL; 757 return 0; 758 } 759 760 #ifdef WITH_ZLIB 761 static int 762 start_compression_out(struct ssh *ssh, int level) 763 { 764 if (level < 1 || level > 9) 765 return SSH_ERR_INVALID_ARGUMENT; 766 debug("Enabling compression at level %d.", level); 767 if (ssh->state->compression_out_started == 1) 768 deflateEnd(&ssh->state->compression_out_stream); 769 switch (deflateInit(&ssh->state->compression_out_stream, level)) { 770 case Z_OK: 771 ssh->state->compression_out_started = 1; 772 break; 773 case Z_MEM_ERROR: 774 return SSH_ERR_ALLOC_FAIL; 775 default: 776 return SSH_ERR_INTERNAL_ERROR; 777 } 778 return 0; 779 } 780 781 static int 782 start_compression_in(struct ssh *ssh) 783 { 784 if (ssh->state->compression_in_started == 1) 785 inflateEnd(&ssh->state->compression_in_stream); 786 switch (inflateInit(&ssh->state->compression_in_stream)) { 787 case Z_OK: 788 ssh->state->compression_in_started = 1; 789 break; 790 case Z_MEM_ERROR: 791 return SSH_ERR_ALLOC_FAIL; 792 default: 793 return SSH_ERR_INTERNAL_ERROR; 794 } 795 return 0; 796 } 797 798 /* XXX remove need for separate compression buffer */ 799 static int 800 compress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out) 801 { 802 u_char buf[4096]; 803 int r, status; 804 805 if (ssh->state->compression_out_started != 1) 806 return SSH_ERR_INTERNAL_ERROR; 807 808 /* This case is not handled below. */ 809 if (sshbuf_len(in) == 0) 810 return 0; 811 812 /* Input is the contents of the input buffer. */ 813 if ((ssh->state->compression_out_stream.next_in = 814 sshbuf_mutable_ptr(in)) == NULL) 815 return SSH_ERR_INTERNAL_ERROR; 816 ssh->state->compression_out_stream.avail_in = sshbuf_len(in); 817 818 /* Loop compressing until deflate() returns with avail_out != 0. */ 819 do { 820 /* Set up fixed-size output buffer. */ 821 ssh->state->compression_out_stream.next_out = buf; 822 ssh->state->compression_out_stream.avail_out = sizeof(buf); 823 824 /* Compress as much data into the buffer as possible. */ 825 status = deflate(&ssh->state->compression_out_stream, 826 Z_PARTIAL_FLUSH); 827 switch (status) { 828 case Z_MEM_ERROR: 829 return SSH_ERR_ALLOC_FAIL; 830 case Z_OK: 831 /* Append compressed data to output_buffer. */ 832 if ((r = sshbuf_put(out, buf, sizeof(buf) - 833 ssh->state->compression_out_stream.avail_out)) != 0) 834 return r; 835 break; 836 case Z_STREAM_ERROR: 837 default: 838 ssh->state->compression_out_failures++; 839 return SSH_ERR_INVALID_FORMAT; 840 } 841 } while (ssh->state->compression_out_stream.avail_out == 0); 842 return 0; 843 } 844 845 static int 846 uncompress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out) 847 { 848 u_char buf[4096]; 849 int r, status; 850 851 if (ssh->state->compression_in_started != 1) 852 return SSH_ERR_INTERNAL_ERROR; 853 854 if ((ssh->state->compression_in_stream.next_in = 855 sshbuf_mutable_ptr(in)) == NULL) 856 return SSH_ERR_INTERNAL_ERROR; 857 ssh->state->compression_in_stream.avail_in = sshbuf_len(in); 858 859 for (;;) { 860 /* Set up fixed-size output buffer. */ 861 ssh->state->compression_in_stream.next_out = buf; 862 ssh->state->compression_in_stream.avail_out = sizeof(buf); 863 864 status = inflate(&ssh->state->compression_in_stream, 865 Z_SYNC_FLUSH); 866 switch (status) { 867 case Z_OK: 868 if ((r = sshbuf_put(out, buf, sizeof(buf) - 869 ssh->state->compression_in_stream.avail_out)) != 0) 870 return r; 871 break; 872 case Z_BUF_ERROR: 873 /* 874 * Comments in zlib.h say that we should keep calling 875 * inflate() until we get an error. This appears to 876 * be the error that we get. 877 */ 878 return 0; 879 case Z_DATA_ERROR: 880 return SSH_ERR_INVALID_FORMAT; 881 case Z_MEM_ERROR: 882 return SSH_ERR_ALLOC_FAIL; 883 case Z_STREAM_ERROR: 884 default: 885 ssh->state->compression_in_failures++; 886 return SSH_ERR_INTERNAL_ERROR; 887 } 888 } 889 /* NOTREACHED */ 890 } 891 892 #else /* WITH_ZLIB */ 893 894 static int 895 start_compression_out(struct ssh *ssh, int level) 896 { 897 return SSH_ERR_INTERNAL_ERROR; 898 } 899 900 static int 901 start_compression_in(struct ssh *ssh) 902 { 903 return SSH_ERR_INTERNAL_ERROR; 904 } 905 906 static int 907 compress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out) 908 { 909 return SSH_ERR_INTERNAL_ERROR; 910 } 911 912 static int 913 uncompress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out) 914 { 915 return SSH_ERR_INTERNAL_ERROR; 916 } 917 #endif /* WITH_ZLIB */ 918 919 void 920 ssh_clear_newkeys(struct ssh *ssh, int mode) 921 { 922 if (ssh->kex && ssh->kex->newkeys[mode]) { 923 kex_free_newkeys(ssh->kex->newkeys[mode]); 924 ssh->kex->newkeys[mode] = NULL; 925 } 926 } 927 928 int 929 ssh_set_newkeys(struct ssh *ssh, int mode) 930 { 931 struct session_state *state = ssh->state; 932 struct sshenc *enc; 933 struct sshmac *mac; 934 struct sshcomp *comp; 935 struct sshcipher_ctx **ccp; 936 struct packet_state *ps; 937 u_int64_t *max_blocks; 938 const char *wmsg; 939 int r, crypt_type; 940 const char *dir = mode == MODE_OUT ? "out" : "in"; 941 942 debug2_f("mode %d", mode); 943 944 if (mode == MODE_OUT) { 945 ccp = &state->send_context; 946 crypt_type = CIPHER_ENCRYPT; 947 ps = &state->p_send; 948 max_blocks = &state->max_blocks_out; 949 } else { 950 ccp = &state->receive_context; 951 crypt_type = CIPHER_DECRYPT; 952 ps = &state->p_read; 953 max_blocks = &state->max_blocks_in; 954 } 955 if (state->newkeys[mode] != NULL) { 956 debug_f("rekeying %s, input %llu bytes %llu blocks, " 957 "output %llu bytes %llu blocks", dir, 958 (unsigned long long)state->p_read.bytes, 959 (unsigned long long)state->p_read.blocks, 960 (unsigned long long)state->p_send.bytes, 961 (unsigned long long)state->p_send.blocks); 962 kex_free_newkeys(state->newkeys[mode]); 963 state->newkeys[mode] = NULL; 964 } 965 /* note that both bytes and the seqnr are not reset */ 966 ps->packets = ps->blocks = 0; 967 /* move newkeys from kex to state */ 968 if ((state->newkeys[mode] = ssh->kex->newkeys[mode]) == NULL) 969 return SSH_ERR_INTERNAL_ERROR; 970 ssh->kex->newkeys[mode] = NULL; 971 enc = &state->newkeys[mode]->enc; 972 mac = &state->newkeys[mode]->mac; 973 comp = &state->newkeys[mode]->comp; 974 if (cipher_authlen(enc->cipher) == 0) { 975 if ((r = mac_init(mac)) != 0) 976 return r; 977 } 978 mac->enabled = 1; 979 DBG(debug_f("cipher_init: %s", dir)); 980 cipher_free(*ccp); 981 *ccp = NULL; 982 if ((r = cipher_init(ccp, enc->cipher, enc->key, enc->key_len, 983 enc->iv, enc->iv_len, crypt_type)) != 0) 984 return r; 985 if (!state->cipher_warning_done && 986 (wmsg = cipher_warning_message(*ccp)) != NULL) { 987 error("Warning: %s", wmsg); 988 state->cipher_warning_done = 1; 989 } 990 /* Deleting the keys does not gain extra security */ 991 /* explicit_bzero(enc->iv, enc->block_size); 992 explicit_bzero(enc->key, enc->key_len); 993 explicit_bzero(mac->key, mac->key_len); */ 994 if (((comp->type == COMP_DELAYED && state->after_authentication)) && 995 comp->enabled == 0) { 996 if ((r = ssh_packet_init_compression(ssh)) < 0) 997 return r; 998 if (mode == MODE_OUT) { 999 if ((r = start_compression_out(ssh, 6)) != 0) 1000 return r; 1001 } else { 1002 if ((r = start_compression_in(ssh)) != 0) 1003 return r; 1004 } 1005 comp->enabled = 1; 1006 } 1007 /* 1008 * The 2^(blocksize*2) limit is too expensive for 3DES, 1009 * so enforce a 1GB limit for small blocksizes. 1010 * See RFC4344 section 3.2. 1011 */ 1012 if (enc->block_size >= 16) 1013 *max_blocks = (u_int64_t)1 << (enc->block_size*2); 1014 else 1015 *max_blocks = ((u_int64_t)1 << 30) / enc->block_size; 1016 if (state->rekey_limit) 1017 *max_blocks = MINIMUM(*max_blocks, 1018 state->rekey_limit / enc->block_size); 1019 debug("rekey %s after %llu blocks", dir, 1020 (unsigned long long)*max_blocks); 1021 return 0; 1022 } 1023 1024 #define MAX_PACKETS (1U<<31) 1025 static int 1026 ssh_packet_need_rekeying(struct ssh *ssh, u_int outbound_packet_len) 1027 { 1028 struct session_state *state = ssh->state; 1029 u_int32_t out_blocks; 1030 1031 /* XXX client can't cope with rekeying pre-auth */ 1032 if (!state->after_authentication) 1033 return 0; 1034 1035 /* Haven't keyed yet or KEX in progress. */ 1036 if (ssh_packet_is_rekeying(ssh)) 1037 return 0; 1038 1039 /* Peer can't rekey */ 1040 if (ssh->compat & SSH_BUG_NOREKEY) 1041 return 0; 1042 1043 /* 1044 * Permit one packet in or out per rekey - this allows us to 1045 * make progress when rekey limits are very small. 1046 */ 1047 if (state->p_send.packets == 0 && state->p_read.packets == 0) 1048 return 0; 1049 1050 /* Time-based rekeying */ 1051 if (state->rekey_interval != 0 && 1052 (int64_t)state->rekey_time + state->rekey_interval <= monotime()) 1053 return 1; 1054 1055 /* 1056 * Always rekey when MAX_PACKETS sent in either direction 1057 * As per RFC4344 section 3.1 we do this after 2^31 packets. 1058 */ 1059 if (state->p_send.packets > MAX_PACKETS || 1060 state->p_read.packets > MAX_PACKETS) 1061 return 1; 1062 1063 /* Rekey after (cipher-specific) maximum blocks */ 1064 out_blocks = ROUNDUP(outbound_packet_len, 1065 state->newkeys[MODE_OUT]->enc.block_size); 1066 return (state->max_blocks_out && 1067 (state->p_send.blocks + out_blocks > state->max_blocks_out)) || 1068 (state->max_blocks_in && 1069 (state->p_read.blocks > state->max_blocks_in)); 1070 } 1071 1072 int 1073 ssh_packet_check_rekey(struct ssh *ssh) 1074 { 1075 if (!ssh_packet_need_rekeying(ssh, 0)) 1076 return 0; 1077 debug3_f("rekex triggered"); 1078 return kex_start_rekex(ssh); 1079 } 1080 1081 /* 1082 * Delayed compression for SSH2 is enabled after authentication: 1083 * This happens on the server side after a SSH2_MSG_USERAUTH_SUCCESS is sent, 1084 * and on the client side after a SSH2_MSG_USERAUTH_SUCCESS is received. 1085 */ 1086 static int 1087 ssh_packet_enable_delayed_compress(struct ssh *ssh) 1088 { 1089 struct session_state *state = ssh->state; 1090 struct sshcomp *comp = NULL; 1091 int r, mode; 1092 1093 /* 1094 * Remember that we are past the authentication step, so rekeying 1095 * with COMP_DELAYED will turn on compression immediately. 1096 */ 1097 state->after_authentication = 1; 1098 for (mode = 0; mode < MODE_MAX; mode++) { 1099 /* protocol error: USERAUTH_SUCCESS received before NEWKEYS */ 1100 if (state->newkeys[mode] == NULL) 1101 continue; 1102 comp = &state->newkeys[mode]->comp; 1103 if (comp && !comp->enabled && comp->type == COMP_DELAYED) { 1104 if ((r = ssh_packet_init_compression(ssh)) != 0) 1105 return r; 1106 if (mode == MODE_OUT) { 1107 if ((r = start_compression_out(ssh, 6)) != 0) 1108 return r; 1109 } else { 1110 if ((r = start_compression_in(ssh)) != 0) 1111 return r; 1112 } 1113 comp->enabled = 1; 1114 } 1115 } 1116 return 0; 1117 } 1118 1119 /* Used to mute debug logging for noisy packet types */ 1120 int 1121 ssh_packet_log_type(u_char type) 1122 { 1123 switch (type) { 1124 case SSH2_MSG_PING: 1125 case SSH2_MSG_PONG: 1126 case SSH2_MSG_CHANNEL_DATA: 1127 case SSH2_MSG_CHANNEL_EXTENDED_DATA: 1128 case SSH2_MSG_CHANNEL_WINDOW_ADJUST: 1129 return 0; 1130 default: 1131 return 1; 1132 } 1133 } 1134 1135 /* 1136 * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue) 1137 */ 1138 int 1139 ssh_packet_send2_wrapped(struct ssh *ssh) 1140 { 1141 struct session_state *state = ssh->state; 1142 u_char type, *cp, macbuf[SSH_DIGEST_MAX_LENGTH]; 1143 u_char tmp, padlen, pad = 0; 1144 u_int authlen = 0, aadlen = 0; 1145 u_int len; 1146 struct sshenc *enc = NULL; 1147 struct sshmac *mac = NULL; 1148 struct sshcomp *comp = NULL; 1149 int r, block_size; 1150 1151 if (state->newkeys[MODE_OUT] != NULL) { 1152 enc = &state->newkeys[MODE_OUT]->enc; 1153 mac = &state->newkeys[MODE_OUT]->mac; 1154 comp = &state->newkeys[MODE_OUT]->comp; 1155 /* disable mac for authenticated encryption */ 1156 if ((authlen = cipher_authlen(enc->cipher)) != 0) 1157 mac = NULL; 1158 } 1159 block_size = enc ? enc->block_size : 8; 1160 aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0; 1161 1162 type = (sshbuf_ptr(state->outgoing_packet))[5]; 1163 if (ssh_packet_log_type(type)) 1164 debug3("send packet: type %u", type); 1165 #ifdef PACKET_DEBUG 1166 fprintf(stderr, "plain: "); 1167 sshbuf_dump(state->outgoing_packet, stderr); 1168 #endif 1169 1170 if (comp && comp->enabled) { 1171 len = sshbuf_len(state->outgoing_packet); 1172 /* skip header, compress only payload */ 1173 if ((r = sshbuf_consume(state->outgoing_packet, 5)) != 0) 1174 goto out; 1175 sshbuf_reset(state->compression_buffer); 1176 if ((r = compress_buffer(ssh, state->outgoing_packet, 1177 state->compression_buffer)) != 0) 1178 goto out; 1179 sshbuf_reset(state->outgoing_packet); 1180 if ((r = sshbuf_put(state->outgoing_packet, 1181 "\0\0\0\0\0", 5)) != 0 || 1182 (r = sshbuf_putb(state->outgoing_packet, 1183 state->compression_buffer)) != 0) 1184 goto out; 1185 DBG(debug("compression: raw %d compressed %zd", len, 1186 sshbuf_len(state->outgoing_packet))); 1187 } 1188 1189 /* sizeof (packet_len + pad_len + payload) */ 1190 len = sshbuf_len(state->outgoing_packet); 1191 1192 /* 1193 * calc size of padding, alloc space, get random data, 1194 * minimum padding is 4 bytes 1195 */ 1196 len -= aadlen; /* packet length is not encrypted for EtM modes */ 1197 padlen = block_size - (len % block_size); 1198 if (padlen < 4) 1199 padlen += block_size; 1200 if (state->extra_pad) { 1201 tmp = state->extra_pad; 1202 state->extra_pad = 1203 ROUNDUP(state->extra_pad, block_size); 1204 /* check if roundup overflowed */ 1205 if (state->extra_pad < tmp) 1206 return SSH_ERR_INVALID_ARGUMENT; 1207 tmp = (len + padlen) % state->extra_pad; 1208 /* Check whether pad calculation below will underflow */ 1209 if (tmp > state->extra_pad) 1210 return SSH_ERR_INVALID_ARGUMENT; 1211 pad = state->extra_pad - tmp; 1212 DBG(debug3_f("adding %d (len %d padlen %d extra_pad %d)", 1213 pad, len, padlen, state->extra_pad)); 1214 tmp = padlen; 1215 padlen += pad; 1216 /* Check whether padlen calculation overflowed */ 1217 if (padlen < tmp) 1218 return SSH_ERR_INVALID_ARGUMENT; /* overflow */ 1219 state->extra_pad = 0; 1220 } 1221 if ((r = sshbuf_reserve(state->outgoing_packet, padlen, &cp)) != 0) 1222 goto out; 1223 if (enc && !cipher_ctx_is_plaintext(state->send_context)) { 1224 /* random padding */ 1225 arc4random_buf(cp, padlen); 1226 } else { 1227 /* clear padding */ 1228 explicit_bzero(cp, padlen); 1229 } 1230 /* sizeof (packet_len + pad_len + payload + padding) */ 1231 len = sshbuf_len(state->outgoing_packet); 1232 cp = sshbuf_mutable_ptr(state->outgoing_packet); 1233 if (cp == NULL) { 1234 r = SSH_ERR_INTERNAL_ERROR; 1235 goto out; 1236 } 1237 /* packet_length includes payload, padding and padding length field */ 1238 POKE_U32(cp, len - 4); 1239 cp[4] = padlen; 1240 DBG(debug("send: len %d (includes padlen %d, aadlen %d)", 1241 len, padlen, aadlen)); 1242 1243 /* compute MAC over seqnr and packet(length fields, payload, padding) */ 1244 if (mac && mac->enabled && !mac->etm) { 1245 if ((r = mac_compute(mac, state->p_send.seqnr, 1246 sshbuf_ptr(state->outgoing_packet), len, 1247 macbuf, sizeof(macbuf))) != 0) 1248 goto out; 1249 DBG(debug("done calc MAC out #%d", state->p_send.seqnr)); 1250 } 1251 /* encrypt packet and append to output buffer. */ 1252 if ((r = sshbuf_reserve(state->output, 1253 sshbuf_len(state->outgoing_packet) + authlen, &cp)) != 0) 1254 goto out; 1255 if ((r = cipher_crypt(state->send_context, state->p_send.seqnr, cp, 1256 sshbuf_ptr(state->outgoing_packet), 1257 len - aadlen, aadlen, authlen)) != 0) 1258 goto out; 1259 /* append unencrypted MAC */ 1260 if (mac && mac->enabled) { 1261 if (mac->etm) { 1262 /* EtM: compute mac over aadlen + cipher text */ 1263 if ((r = mac_compute(mac, state->p_send.seqnr, 1264 cp, len, macbuf, sizeof(macbuf))) != 0) 1265 goto out; 1266 DBG(debug("done calc MAC(EtM) out #%d", 1267 state->p_send.seqnr)); 1268 } 1269 if ((r = sshbuf_put(state->output, macbuf, mac->mac_len)) != 0) 1270 goto out; 1271 } 1272 #ifdef PACKET_DEBUG 1273 fprintf(stderr, "encrypted: "); 1274 sshbuf_dump(state->output, stderr); 1275 #endif 1276 /* increment sequence number for outgoing packets */ 1277 if (++state->p_send.seqnr == 0) { 1278 if ((ssh->kex->flags & KEX_INITIAL) != 0) { 1279 ssh_packet_disconnect(ssh, "outgoing sequence number " 1280 "wrapped during initial key exchange"); 1281 } 1282 logit("outgoing seqnr wraps around"); 1283 } 1284 if (++state->p_send.packets == 0) 1285 if (!(ssh->compat & SSH_BUG_NOREKEY)) 1286 return SSH_ERR_NEED_REKEY; 1287 state->p_send.blocks += len / block_size; 1288 state->p_send.bytes += len; 1289 sshbuf_reset(state->outgoing_packet); 1290 1291 if (type == SSH2_MSG_NEWKEYS && ssh->kex->kex_strict) { 1292 debug_f("resetting send seqnr %u", state->p_send.seqnr); 1293 state->p_send.seqnr = 0; 1294 } 1295 1296 if (type == SSH2_MSG_NEWKEYS) 1297 r = ssh_set_newkeys(ssh, MODE_OUT); 1298 else if (type == SSH2_MSG_USERAUTH_SUCCESS && state->server_side) 1299 r = ssh_packet_enable_delayed_compress(ssh); 1300 else 1301 r = 0; 1302 out: 1303 return r; 1304 } 1305 1306 /* returns non-zero if the specified packet type is usec by KEX */ 1307 static int 1308 ssh_packet_type_is_kex(u_char type) 1309 { 1310 return 1311 type >= SSH2_MSG_TRANSPORT_MIN && 1312 type <= SSH2_MSG_TRANSPORT_MAX && 1313 type != SSH2_MSG_SERVICE_REQUEST && 1314 type != SSH2_MSG_SERVICE_ACCEPT && 1315 type != SSH2_MSG_EXT_INFO; 1316 } 1317 1318 int 1319 ssh_packet_send2(struct ssh *ssh) 1320 { 1321 struct session_state *state = ssh->state; 1322 struct packet *p; 1323 u_char type; 1324 int r, need_rekey; 1325 1326 if (sshbuf_len(state->outgoing_packet) < 6) 1327 return SSH_ERR_INTERNAL_ERROR; 1328 type = sshbuf_ptr(state->outgoing_packet)[5]; 1329 need_rekey = !ssh_packet_type_is_kex(type) && 1330 ssh_packet_need_rekeying(ssh, sshbuf_len(state->outgoing_packet)); 1331 1332 /* 1333 * During rekeying we can only send key exchange messages. 1334 * Queue everything else. 1335 */ 1336 if ((need_rekey || state->rekeying) && !ssh_packet_type_is_kex(type)) { 1337 if (need_rekey) 1338 debug3_f("rekex triggered"); 1339 debug("enqueue packet: %u", type); 1340 p = calloc(1, sizeof(*p)); 1341 if (p == NULL) 1342 return SSH_ERR_ALLOC_FAIL; 1343 p->type = type; 1344 p->payload = state->outgoing_packet; 1345 TAILQ_INSERT_TAIL(&state->outgoing, p, next); 1346 state->outgoing_packet = sshbuf_new(); 1347 if (state->outgoing_packet == NULL) 1348 return SSH_ERR_ALLOC_FAIL; 1349 if (need_rekey) { 1350 /* 1351 * This packet triggered a rekey, so send the 1352 * KEXINIT now. 1353 * NB. reenters this function via kex_start_rekex(). 1354 */ 1355 return kex_start_rekex(ssh); 1356 } 1357 return 0; 1358 } 1359 1360 /* rekeying starts with sending KEXINIT */ 1361 if (type == SSH2_MSG_KEXINIT) 1362 state->rekeying = 1; 1363 1364 if ((r = ssh_packet_send2_wrapped(ssh)) != 0) 1365 return r; 1366 1367 /* after a NEWKEYS message we can send the complete queue */ 1368 if (type == SSH2_MSG_NEWKEYS) { 1369 state->rekeying = 0; 1370 state->rekey_time = monotime(); 1371 while ((p = TAILQ_FIRST(&state->outgoing))) { 1372 type = p->type; 1373 /* 1374 * If this packet triggers a rekex, then skip the 1375 * remaining packets in the queue for now. 1376 * NB. re-enters this function via kex_start_rekex. 1377 */ 1378 if (ssh_packet_need_rekeying(ssh, 1379 sshbuf_len(p->payload))) { 1380 debug3_f("queued packet triggered rekex"); 1381 return kex_start_rekex(ssh); 1382 } 1383 debug("dequeue packet: %u", type); 1384 sshbuf_free(state->outgoing_packet); 1385 state->outgoing_packet = p->payload; 1386 TAILQ_REMOVE(&state->outgoing, p, next); 1387 memset(p, 0, sizeof(*p)); 1388 free(p); 1389 if ((r = ssh_packet_send2_wrapped(ssh)) != 0) 1390 return r; 1391 } 1392 } 1393 return 0; 1394 } 1395 1396 /* 1397 * Waits until a packet has been received, and returns its type. Note that 1398 * no other data is processed until this returns, so this function should not 1399 * be used during the interactive session. 1400 */ 1401 1402 int 1403 ssh_packet_read_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1404 { 1405 struct session_state *state = ssh->state; 1406 int len, r, ms_remain = 0; 1407 struct pollfd pfd; 1408 char buf[8192]; 1409 struct timeval start; 1410 struct timespec timespec, *timespecp = NULL; 1411 1412 DBG(debug("packet_read()")); 1413 1414 /* 1415 * Since we are blocking, ensure that all written packets have 1416 * been sent. 1417 */ 1418 if ((r = ssh_packet_write_wait(ssh)) != 0) 1419 goto out; 1420 1421 /* Stay in the loop until we have received a complete packet. */ 1422 for (;;) { 1423 /* Try to read a packet from the buffer. */ 1424 if ((r = ssh_packet_read_poll_seqnr(ssh, typep, seqnr_p)) != 0) 1425 break; 1426 /* If we got a packet, return it. */ 1427 if (*typep != SSH_MSG_NONE) 1428 break; 1429 /* 1430 * Otherwise, wait for some data to arrive, add it to the 1431 * buffer, and try again. 1432 */ 1433 pfd.fd = state->connection_in; 1434 pfd.events = POLLIN; 1435 1436 if (state->packet_timeout_ms > 0) { 1437 ms_remain = state->packet_timeout_ms; 1438 timespecp = ×pec; 1439 } 1440 /* Wait for some data to arrive. */ 1441 for (;;) { 1442 if (state->packet_timeout_ms > 0) { 1443 ms_to_timespec(×pec, ms_remain); 1444 monotime_tv(&start); 1445 } 1446 if ((r = ppoll(&pfd, 1, timespecp, NULL)) >= 0) 1447 break; 1448 if (errno != EAGAIN && errno != EINTR) { 1449 r = SSH_ERR_SYSTEM_ERROR; 1450 goto out; 1451 } 1452 if (state->packet_timeout_ms <= 0) 1453 continue; 1454 ms_subtract_diff(&start, &ms_remain); 1455 if (ms_remain <= 0) { 1456 r = 0; 1457 break; 1458 } 1459 } 1460 if (r == 0) { 1461 r = SSH_ERR_CONN_TIMEOUT; 1462 goto out; 1463 } 1464 /* Read data from the socket. */ 1465 len = read(state->connection_in, buf, sizeof(buf)); 1466 if (len == 0) { 1467 r = SSH_ERR_CONN_CLOSED; 1468 goto out; 1469 } 1470 if (len == -1) { 1471 r = SSH_ERR_SYSTEM_ERROR; 1472 goto out; 1473 } 1474 1475 /* Append it to the buffer. */ 1476 if ((r = ssh_packet_process_incoming(ssh, buf, len)) != 0) 1477 goto out; 1478 } 1479 out: 1480 return r; 1481 } 1482 1483 int 1484 ssh_packet_read(struct ssh *ssh) 1485 { 1486 u_char type; 1487 int r; 1488 1489 if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0) 1490 fatal_fr(r, "read"); 1491 return type; 1492 } 1493 1494 static int 1495 ssh_packet_read_poll2_mux(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1496 { 1497 struct session_state *state = ssh->state; 1498 const u_char *cp; 1499 size_t need; 1500 int r; 1501 1502 if (ssh->kex) 1503 return SSH_ERR_INTERNAL_ERROR; 1504 *typep = SSH_MSG_NONE; 1505 cp = sshbuf_ptr(state->input); 1506 if (state->packlen == 0) { 1507 if (sshbuf_len(state->input) < 4 + 1) 1508 return 0; /* packet is incomplete */ 1509 state->packlen = PEEK_U32(cp); 1510 if (state->packlen < 4 + 1 || 1511 state->packlen > PACKET_MAX_SIZE) 1512 return SSH_ERR_MESSAGE_INCOMPLETE; 1513 } 1514 need = state->packlen + 4; 1515 if (sshbuf_len(state->input) < need) 1516 return 0; /* packet is incomplete */ 1517 sshbuf_reset(state->incoming_packet); 1518 if ((r = sshbuf_put(state->incoming_packet, cp + 4, 1519 state->packlen)) != 0 || 1520 (r = sshbuf_consume(state->input, need)) != 0 || 1521 (r = sshbuf_get_u8(state->incoming_packet, NULL)) != 0 || 1522 (r = sshbuf_get_u8(state->incoming_packet, typep)) != 0) 1523 return r; 1524 if (ssh_packet_log_type(*typep)) 1525 debug3_f("type %u", *typep); 1526 /* sshbuf_dump(state->incoming_packet, stderr); */ 1527 /* reset for next packet */ 1528 state->packlen = 0; 1529 return r; 1530 } 1531 1532 int 1533 ssh_packet_read_poll2(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1534 { 1535 struct session_state *state = ssh->state; 1536 u_int padlen, need; 1537 u_char *cp; 1538 u_int maclen, aadlen = 0, authlen = 0, block_size; 1539 struct sshenc *enc = NULL; 1540 struct sshmac *mac = NULL; 1541 struct sshcomp *comp = NULL; 1542 int r; 1543 1544 if (state->mux) 1545 return ssh_packet_read_poll2_mux(ssh, typep, seqnr_p); 1546 1547 *typep = SSH_MSG_NONE; 1548 1549 if (state->packet_discard) 1550 return 0; 1551 1552 if (state->newkeys[MODE_IN] != NULL) { 1553 enc = &state->newkeys[MODE_IN]->enc; 1554 mac = &state->newkeys[MODE_IN]->mac; 1555 comp = &state->newkeys[MODE_IN]->comp; 1556 /* disable mac for authenticated encryption */ 1557 if ((authlen = cipher_authlen(enc->cipher)) != 0) 1558 mac = NULL; 1559 } 1560 maclen = mac && mac->enabled ? mac->mac_len : 0; 1561 block_size = enc ? enc->block_size : 8; 1562 aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0; 1563 1564 if (aadlen && state->packlen == 0) { 1565 if (cipher_get_length(state->receive_context, 1566 &state->packlen, state->p_read.seqnr, 1567 sshbuf_ptr(state->input), sshbuf_len(state->input)) != 0) 1568 return 0; 1569 if (state->packlen < 1 + 4 || 1570 state->packlen > PACKET_MAX_SIZE) { 1571 #ifdef PACKET_DEBUG 1572 sshbuf_dump(state->input, stderr); 1573 #endif 1574 logit("Bad packet length %u.", state->packlen); 1575 if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0) 1576 return r; 1577 return SSH_ERR_CONN_CORRUPT; 1578 } 1579 sshbuf_reset(state->incoming_packet); 1580 } else if (state->packlen == 0) { 1581 /* 1582 * check if input size is less than the cipher block size, 1583 * decrypt first block and extract length of incoming packet 1584 */ 1585 if (sshbuf_len(state->input) < block_size) 1586 return 0; 1587 sshbuf_reset(state->incoming_packet); 1588 if ((r = sshbuf_reserve(state->incoming_packet, block_size, 1589 &cp)) != 0) 1590 goto out; 1591 if ((r = cipher_crypt(state->receive_context, 1592 state->p_send.seqnr, cp, sshbuf_ptr(state->input), 1593 block_size, 0, 0)) != 0) 1594 goto out; 1595 state->packlen = PEEK_U32(sshbuf_ptr(state->incoming_packet)); 1596 if (state->packlen < 1 + 4 || 1597 state->packlen > PACKET_MAX_SIZE) { 1598 #ifdef PACKET_DEBUG 1599 fprintf(stderr, "input: \n"); 1600 sshbuf_dump(state->input, stderr); 1601 fprintf(stderr, "incoming_packet: \n"); 1602 sshbuf_dump(state->incoming_packet, stderr); 1603 #endif 1604 logit("Bad packet length %u.", state->packlen); 1605 return ssh_packet_start_discard(ssh, enc, mac, 0, 1606 PACKET_MAX_SIZE); 1607 } 1608 if ((r = sshbuf_consume(state->input, block_size)) != 0) 1609 goto out; 1610 } 1611 DBG(debug("input: packet len %u", state->packlen+4)); 1612 1613 if (aadlen) { 1614 /* only the payload is encrypted */ 1615 need = state->packlen; 1616 } else { 1617 /* 1618 * the payload size and the payload are encrypted, but we 1619 * have a partial packet of block_size bytes 1620 */ 1621 need = 4 + state->packlen - block_size; 1622 } 1623 DBG(debug("partial packet: block %d, need %d, maclen %d, authlen %d," 1624 " aadlen %d", block_size, need, maclen, authlen, aadlen)); 1625 if (need % block_size != 0) { 1626 logit("padding error: need %d block %d mod %d", 1627 need, block_size, need % block_size); 1628 return ssh_packet_start_discard(ssh, enc, mac, 0, 1629 PACKET_MAX_SIZE - block_size); 1630 } 1631 /* 1632 * check if the entire packet has been received and 1633 * decrypt into incoming_packet: 1634 * 'aadlen' bytes are unencrypted, but authenticated. 1635 * 'need' bytes are encrypted, followed by either 1636 * 'authlen' bytes of authentication tag or 1637 * 'maclen' bytes of message authentication code. 1638 */ 1639 if (sshbuf_len(state->input) < aadlen + need + authlen + maclen) 1640 return 0; /* packet is incomplete */ 1641 #ifdef PACKET_DEBUG 1642 fprintf(stderr, "read_poll enc/full: "); 1643 sshbuf_dump(state->input, stderr); 1644 #endif 1645 /* EtM: check mac over encrypted input */ 1646 if (mac && mac->enabled && mac->etm) { 1647 if ((r = mac_check(mac, state->p_read.seqnr, 1648 sshbuf_ptr(state->input), aadlen + need, 1649 sshbuf_ptr(state->input) + aadlen + need + authlen, 1650 maclen)) != 0) { 1651 if (r == SSH_ERR_MAC_INVALID) 1652 logit("Corrupted MAC on input."); 1653 goto out; 1654 } 1655 } 1656 if ((r = sshbuf_reserve(state->incoming_packet, aadlen + need, 1657 &cp)) != 0) 1658 goto out; 1659 if ((r = cipher_crypt(state->receive_context, state->p_read.seqnr, cp, 1660 sshbuf_ptr(state->input), need, aadlen, authlen)) != 0) 1661 goto out; 1662 if ((r = sshbuf_consume(state->input, aadlen + need + authlen)) != 0) 1663 goto out; 1664 if (mac && mac->enabled) { 1665 /* Not EtM: check MAC over cleartext */ 1666 if (!mac->etm && (r = mac_check(mac, state->p_read.seqnr, 1667 sshbuf_ptr(state->incoming_packet), 1668 sshbuf_len(state->incoming_packet), 1669 sshbuf_ptr(state->input), maclen)) != 0) { 1670 if (r != SSH_ERR_MAC_INVALID) 1671 goto out; 1672 logit("Corrupted MAC on input."); 1673 if (need + block_size > PACKET_MAX_SIZE) 1674 return SSH_ERR_INTERNAL_ERROR; 1675 return ssh_packet_start_discard(ssh, enc, mac, 1676 sshbuf_len(state->incoming_packet), 1677 PACKET_MAX_SIZE - need - block_size); 1678 } 1679 /* Remove MAC from input buffer */ 1680 DBG(debug("MAC #%d ok", state->p_read.seqnr)); 1681 if ((r = sshbuf_consume(state->input, mac->mac_len)) != 0) 1682 goto out; 1683 } 1684 1685 if (seqnr_p != NULL) 1686 *seqnr_p = state->p_read.seqnr; 1687 if (++state->p_read.seqnr == 0) { 1688 if ((ssh->kex->flags & KEX_INITIAL) != 0) { 1689 ssh_packet_disconnect(ssh, "incoming sequence number " 1690 "wrapped during initial key exchange"); 1691 } 1692 logit("incoming seqnr wraps around"); 1693 } 1694 if (++state->p_read.packets == 0) 1695 if (!(ssh->compat & SSH_BUG_NOREKEY)) 1696 return SSH_ERR_NEED_REKEY; 1697 state->p_read.blocks += (state->packlen + 4) / block_size; 1698 state->p_read.bytes += state->packlen + 4; 1699 1700 /* get padlen */ 1701 padlen = sshbuf_ptr(state->incoming_packet)[4]; 1702 DBG(debug("input: padlen %d", padlen)); 1703 if (padlen < 4) { 1704 if ((r = sshpkt_disconnect(ssh, 1705 "Corrupted padlen %d on input.", padlen)) != 0 || 1706 (r = ssh_packet_write_wait(ssh)) != 0) 1707 return r; 1708 return SSH_ERR_CONN_CORRUPT; 1709 } 1710 1711 /* skip packet size + padlen, discard padding */ 1712 if ((r = sshbuf_consume(state->incoming_packet, 4 + 1)) != 0 || 1713 ((r = sshbuf_consume_end(state->incoming_packet, padlen)) != 0)) 1714 goto out; 1715 1716 DBG(debug("input: len before de-compress %zd", 1717 sshbuf_len(state->incoming_packet))); 1718 if (comp && comp->enabled) { 1719 sshbuf_reset(state->compression_buffer); 1720 if ((r = uncompress_buffer(ssh, state->incoming_packet, 1721 state->compression_buffer)) != 0) 1722 goto out; 1723 sshbuf_reset(state->incoming_packet); 1724 if ((r = sshbuf_putb(state->incoming_packet, 1725 state->compression_buffer)) != 0) 1726 goto out; 1727 DBG(debug("input: len after de-compress %zd", 1728 sshbuf_len(state->incoming_packet))); 1729 } 1730 /* 1731 * get packet type, implies consume. 1732 * return length of payload (without type field) 1733 */ 1734 if ((r = sshbuf_get_u8(state->incoming_packet, typep)) != 0) 1735 goto out; 1736 if (ssh_packet_log_type(*typep)) 1737 debug3("receive packet: type %u", *typep); 1738 if (*typep < SSH2_MSG_MIN) { 1739 if ((r = sshpkt_disconnect(ssh, 1740 "Invalid ssh2 packet type: %d", *typep)) != 0 || 1741 (r = ssh_packet_write_wait(ssh)) != 0) 1742 return r; 1743 return SSH_ERR_PROTOCOL_ERROR; 1744 } 1745 if (state->hook_in != NULL && 1746 (r = state->hook_in(ssh, state->incoming_packet, typep, 1747 state->hook_in_ctx)) != 0) 1748 return r; 1749 if (*typep == SSH2_MSG_USERAUTH_SUCCESS && !state->server_side) 1750 r = ssh_packet_enable_delayed_compress(ssh); 1751 else 1752 r = 0; 1753 #ifdef PACKET_DEBUG 1754 fprintf(stderr, "read/plain[%d]:\r\n", *typep); 1755 sshbuf_dump(state->incoming_packet, stderr); 1756 #endif 1757 /* reset for next packet */ 1758 state->packlen = 0; 1759 if (*typep == SSH2_MSG_NEWKEYS && ssh->kex->kex_strict) { 1760 debug_f("resetting read seqnr %u", state->p_read.seqnr); 1761 state->p_read.seqnr = 0; 1762 } 1763 1764 if ((r = ssh_packet_check_rekey(ssh)) != 0) 1765 return r; 1766 out: 1767 return r; 1768 } 1769 1770 int 1771 ssh_packet_read_poll_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1772 { 1773 struct session_state *state = ssh->state; 1774 u_int reason, seqnr; 1775 int r; 1776 u_char *msg; 1777 const u_char *d; 1778 size_t len; 1779 1780 for (;;) { 1781 msg = NULL; 1782 r = ssh_packet_read_poll2(ssh, typep, seqnr_p); 1783 if (r != 0) 1784 return r; 1785 if (*typep == 0) { 1786 /* no message ready */ 1787 return 0; 1788 } 1789 state->keep_alive_timeouts = 0; 1790 DBG(debug("received packet type %d", *typep)); 1791 1792 /* Always process disconnect messages */ 1793 if (*typep == SSH2_MSG_DISCONNECT) { 1794 if ((r = sshpkt_get_u32(ssh, &reason)) != 0 || 1795 (r = sshpkt_get_string(ssh, &msg, NULL)) != 0) 1796 return r; 1797 /* Ignore normal client exit notifications */ 1798 do_log2(ssh->state->server_side && 1799 reason == SSH2_DISCONNECT_BY_APPLICATION ? 1800 SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_ERROR, 1801 "Received disconnect from %s port %d:" 1802 "%u: %.400s", ssh_remote_ipaddr(ssh), 1803 ssh_remote_port(ssh), reason, msg); 1804 free(msg); 1805 return SSH_ERR_DISCONNECTED; 1806 } 1807 1808 /* 1809 * Do not implicitly handle any messages here during initial 1810 * KEX when in strict mode. They will be need to be allowed 1811 * explicitly by the KEX dispatch table or they will generate 1812 * protocol errors. 1813 */ 1814 if (ssh->kex != NULL && 1815 (ssh->kex->flags & KEX_INITIAL) && ssh->kex->kex_strict) 1816 return 0; 1817 /* Implicitly handle transport-level messages */ 1818 switch (*typep) { 1819 case SSH2_MSG_IGNORE: 1820 debug3("Received SSH2_MSG_IGNORE"); 1821 break; 1822 case SSH2_MSG_DEBUG: 1823 if ((r = sshpkt_get_u8(ssh, NULL)) != 0 || 1824 (r = sshpkt_get_string(ssh, &msg, NULL)) != 0 || 1825 (r = sshpkt_get_string(ssh, NULL, NULL)) != 0) { 1826 free(msg); 1827 return r; 1828 } 1829 debug("Remote: %.900s", msg); 1830 free(msg); 1831 break; 1832 case SSH2_MSG_UNIMPLEMENTED: 1833 if ((r = sshpkt_get_u32(ssh, &seqnr)) != 0) 1834 return r; 1835 debug("Received SSH2_MSG_UNIMPLEMENTED for %u", 1836 seqnr); 1837 break; 1838 case SSH2_MSG_PING: 1839 if ((r = sshpkt_get_string_direct(ssh, &d, &len)) != 0) 1840 return r; 1841 DBG(debug("Received SSH2_MSG_PING len %zu", len)); 1842 if ((r = sshpkt_start(ssh, SSH2_MSG_PONG)) != 0 || 1843 (r = sshpkt_put_string(ssh, d, len)) != 0 || 1844 (r = sshpkt_send(ssh)) != 0) 1845 return r; 1846 break; 1847 case SSH2_MSG_PONG: 1848 if ((r = sshpkt_get_string_direct(ssh, 1849 NULL, &len)) != 0) 1850 return r; 1851 DBG(debug("Received SSH2_MSG_PONG len %zu", len)); 1852 break; 1853 default: 1854 return 0; 1855 } 1856 } 1857 } 1858 1859 /* 1860 * Buffers the supplied input data. This is intended to be used together 1861 * with packet_read_poll(). 1862 */ 1863 int 1864 ssh_packet_process_incoming(struct ssh *ssh, const char *buf, u_int len) 1865 { 1866 struct session_state *state = ssh->state; 1867 int r; 1868 1869 if (state->packet_discard) { 1870 state->keep_alive_timeouts = 0; /* ?? */ 1871 if (len >= state->packet_discard) { 1872 if ((r = ssh_packet_stop_discard(ssh)) != 0) 1873 return r; 1874 } 1875 state->packet_discard -= len; 1876 return 0; 1877 } 1878 if ((r = sshbuf_put(state->input, buf, len)) != 0) 1879 return r; 1880 1881 return 0; 1882 } 1883 1884 /* Reads and buffers data from the specified fd */ 1885 int 1886 ssh_packet_process_read(struct ssh *ssh, int fd) 1887 { 1888 struct session_state *state = ssh->state; 1889 int r; 1890 size_t rlen; 1891 1892 if ((r = sshbuf_read(fd, state->input, PACKET_MAX_SIZE, &rlen)) != 0) 1893 return r; 1894 1895 if (state->packet_discard) { 1896 if ((r = sshbuf_consume_end(state->input, rlen)) != 0) 1897 return r; 1898 state->keep_alive_timeouts = 0; /* ?? */ 1899 if (rlen >= state->packet_discard) { 1900 if ((r = ssh_packet_stop_discard(ssh)) != 0) 1901 return r; 1902 } 1903 state->packet_discard -= rlen; 1904 return 0; 1905 } 1906 return 0; 1907 } 1908 1909 int 1910 ssh_packet_remaining(struct ssh *ssh) 1911 { 1912 return sshbuf_len(ssh->state->incoming_packet); 1913 } 1914 1915 /* 1916 * Sends a diagnostic message from the server to the client. This message 1917 * can be sent at any time (but not while constructing another message). The 1918 * message is printed immediately, but only if the client is being executed 1919 * in verbose mode. These messages are primarily intended to ease debugging 1920 * authentication problems. The length of the formatted message must not 1921 * exceed 1024 bytes. This will automatically call ssh_packet_write_wait. 1922 */ 1923 void 1924 ssh_packet_send_debug(struct ssh *ssh, const char *fmt,...) 1925 { 1926 char buf[1024]; 1927 va_list args; 1928 int r; 1929 1930 if ((ssh->compat & SSH_BUG_DEBUG)) 1931 return; 1932 1933 va_start(args, fmt); 1934 vsnprintf(buf, sizeof(buf), fmt, args); 1935 va_end(args); 1936 1937 debug3("sending debug message: %s", buf); 1938 1939 if ((r = sshpkt_start(ssh, SSH2_MSG_DEBUG)) != 0 || 1940 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* always display */ 1941 (r = sshpkt_put_cstring(ssh, buf)) != 0 || 1942 (r = sshpkt_put_cstring(ssh, "")) != 0 || 1943 (r = sshpkt_send(ssh)) != 0 || 1944 (r = ssh_packet_write_wait(ssh)) != 0) 1945 fatal_fr(r, "send DEBUG"); 1946 } 1947 1948 void 1949 sshpkt_fmt_connection_id(struct ssh *ssh, char *s, size_t l) 1950 { 1951 snprintf(s, l, "%.200s%s%s port %d", 1952 ssh->log_preamble ? ssh->log_preamble : "", 1953 ssh->log_preamble ? " " : "", 1954 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 1955 } 1956 1957 /* 1958 * Pretty-print connection-terminating errors and exit. 1959 */ 1960 static void 1961 sshpkt_vfatal(struct ssh *ssh, int r, const char *fmt, va_list ap) 1962 { 1963 char *tag = NULL, remote_id[512]; 1964 int oerrno = errno; 1965 1966 sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id)); 1967 1968 switch (r) { 1969 case SSH_ERR_CONN_CLOSED: 1970 ssh_packet_clear_keys(ssh); 1971 logdie("Connection closed by %s", remote_id); 1972 case SSH_ERR_CONN_TIMEOUT: 1973 ssh_packet_clear_keys(ssh); 1974 logdie("Connection %s %s timed out", 1975 ssh->state->server_side ? "from" : "to", remote_id); 1976 case SSH_ERR_DISCONNECTED: 1977 ssh_packet_clear_keys(ssh); 1978 logdie("Disconnected from %s", remote_id); 1979 case SSH_ERR_SYSTEM_ERROR: 1980 if (errno == ECONNRESET) { 1981 ssh_packet_clear_keys(ssh); 1982 logdie("Connection reset by %s", remote_id); 1983 } 1984 /* FALLTHROUGH */ 1985 case SSH_ERR_NO_CIPHER_ALG_MATCH: 1986 case SSH_ERR_NO_MAC_ALG_MATCH: 1987 case SSH_ERR_NO_COMPRESS_ALG_MATCH: 1988 case SSH_ERR_NO_KEX_ALG_MATCH: 1989 case SSH_ERR_NO_HOSTKEY_ALG_MATCH: 1990 if (ssh->kex && ssh->kex->failed_choice) { 1991 ssh_packet_clear_keys(ssh); 1992 errno = oerrno; 1993 logdie("Unable to negotiate with %s: %s. " 1994 "Their offer: %s", remote_id, ssh_err(r), 1995 ssh->kex->failed_choice); 1996 } 1997 /* FALLTHROUGH */ 1998 default: 1999 if (vasprintf(&tag, fmt, ap) == -1) { 2000 ssh_packet_clear_keys(ssh); 2001 logdie_f("could not allocate failure message"); 2002 } 2003 ssh_packet_clear_keys(ssh); 2004 errno = oerrno; 2005 logdie_r(r, "%s%sConnection %s %s", 2006 tag != NULL ? tag : "", tag != NULL ? ": " : "", 2007 ssh->state->server_side ? "from" : "to", remote_id); 2008 } 2009 } 2010 2011 void 2012 sshpkt_fatal(struct ssh *ssh, int r, const char *fmt, ...) 2013 { 2014 va_list ap; 2015 2016 va_start(ap, fmt); 2017 sshpkt_vfatal(ssh, r, fmt, ap); 2018 /* NOTREACHED */ 2019 va_end(ap); 2020 logdie_f("should have exited"); 2021 } 2022 2023 /* 2024 * Logs the error plus constructs and sends a disconnect packet, closes the 2025 * connection, and exits. This function never returns. The error message 2026 * should not contain a newline. The length of the formatted message must 2027 * not exceed 1024 bytes. 2028 */ 2029 void 2030 ssh_packet_disconnect(struct ssh *ssh, const char *fmt,...) 2031 { 2032 char buf[1024], remote_id[512]; 2033 va_list args; 2034 static int disconnecting = 0; 2035 int r; 2036 2037 if (disconnecting) /* Guard against recursive invocations. */ 2038 fatal("packet_disconnect called recursively."); 2039 disconnecting = 1; 2040 2041 /* 2042 * Format the message. Note that the caller must make sure the 2043 * message is of limited size. 2044 */ 2045 sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id)); 2046 va_start(args, fmt); 2047 vsnprintf(buf, sizeof(buf), fmt, args); 2048 va_end(args); 2049 2050 /* Display the error locally */ 2051 logit("Disconnecting %s: %.100s", remote_id, buf); 2052 2053 /* 2054 * Send the disconnect message to the other side, and wait 2055 * for it to get sent. 2056 */ 2057 if ((r = sshpkt_disconnect(ssh, "%s", buf)) != 0) 2058 sshpkt_fatal(ssh, r, "%s", __func__); 2059 2060 if ((r = ssh_packet_write_wait(ssh)) != 0) 2061 sshpkt_fatal(ssh, r, "%s", __func__); 2062 2063 /* Close the connection. */ 2064 ssh_packet_close(ssh); 2065 cleanup_exit(255); 2066 } 2067 2068 /* 2069 * Checks if there is any buffered output, and tries to write some of 2070 * the output. 2071 */ 2072 int 2073 ssh_packet_write_poll(struct ssh *ssh) 2074 { 2075 struct session_state *state = ssh->state; 2076 int len = sshbuf_len(state->output); 2077 int r; 2078 2079 if (len > 0) { 2080 len = write(state->connection_out, 2081 sshbuf_ptr(state->output), len); 2082 if (len == -1) { 2083 if (errno == EINTR || errno == EAGAIN) 2084 return 0; 2085 return SSH_ERR_SYSTEM_ERROR; 2086 } 2087 if (len == 0) 2088 return SSH_ERR_CONN_CLOSED; 2089 if ((r = sshbuf_consume(state->output, len)) != 0) 2090 return r; 2091 } 2092 return 0; 2093 } 2094 2095 /* 2096 * Calls packet_write_poll repeatedly until all pending output data has been 2097 * written. 2098 */ 2099 int 2100 ssh_packet_write_wait(struct ssh *ssh) 2101 { 2102 int ret, r, ms_remain = 0; 2103 struct timeval start; 2104 struct timespec timespec, *timespecp = NULL; 2105 struct session_state *state = ssh->state; 2106 struct pollfd pfd; 2107 2108 if ((r = ssh_packet_write_poll(ssh)) != 0) 2109 return r; 2110 while (ssh_packet_have_data_to_write(ssh)) { 2111 pfd.fd = state->connection_out; 2112 pfd.events = POLLOUT; 2113 2114 if (state->packet_timeout_ms > 0) { 2115 ms_remain = state->packet_timeout_ms; 2116 timespecp = ×pec; 2117 } 2118 for (;;) { 2119 if (state->packet_timeout_ms > 0) { 2120 ms_to_timespec(×pec, ms_remain); 2121 monotime_tv(&start); 2122 } 2123 if ((ret = ppoll(&pfd, 1, timespecp, NULL)) >= 0) 2124 break; 2125 if (errno != EAGAIN && errno != EINTR) 2126 break; 2127 if (state->packet_timeout_ms <= 0) 2128 continue; 2129 ms_subtract_diff(&start, &ms_remain); 2130 if (ms_remain <= 0) { 2131 ret = 0; 2132 break; 2133 } 2134 } 2135 if (ret == 0) 2136 return SSH_ERR_CONN_TIMEOUT; 2137 if ((r = ssh_packet_write_poll(ssh)) != 0) 2138 return r; 2139 } 2140 return 0; 2141 } 2142 2143 /* Returns true if there is buffered data to write to the connection. */ 2144 2145 int 2146 ssh_packet_have_data_to_write(struct ssh *ssh) 2147 { 2148 return sshbuf_len(ssh->state->output) != 0; 2149 } 2150 2151 /* Returns true if there is not too much data to write to the connection. */ 2152 2153 int 2154 ssh_packet_not_very_much_data_to_write(struct ssh *ssh) 2155 { 2156 if (ssh->state->interactive_mode) 2157 return sshbuf_len(ssh->state->output) < 16384; 2158 else 2159 return sshbuf_len(ssh->state->output) < 128 * 1024; 2160 } 2161 2162 /* 2163 * returns true when there are at most a few keystrokes of data to write 2164 * and the connection is in interactive mode. 2165 */ 2166 2167 int 2168 ssh_packet_interactive_data_to_write(struct ssh *ssh) 2169 { 2170 return ssh->state->interactive_mode && 2171 sshbuf_len(ssh->state->output) < 256; 2172 } 2173 2174 void 2175 ssh_packet_set_tos(struct ssh *ssh, int tos) 2176 { 2177 if (!ssh_packet_connection_is_on_socket(ssh) || tos == INT_MAX) 2178 return; 2179 set_sock_tos(ssh->state->connection_in, tos); 2180 } 2181 2182 /* Informs that the current session is interactive. Sets IP flags for that. */ 2183 2184 void 2185 ssh_packet_set_interactive(struct ssh *ssh, int interactive, int qos_interactive, int qos_bulk) 2186 { 2187 struct session_state *state = ssh->state; 2188 2189 if (state->set_interactive_called) 2190 return; 2191 state->set_interactive_called = 1; 2192 2193 /* Record that we are in interactive mode. */ 2194 state->interactive_mode = interactive; 2195 2196 /* Only set socket options if using a socket. */ 2197 if (!ssh_packet_connection_is_on_socket(ssh)) 2198 return; 2199 set_nodelay(state->connection_in); 2200 ssh_packet_set_tos(ssh, interactive ? qos_interactive : qos_bulk); 2201 } 2202 2203 /* Returns true if the current connection is interactive. */ 2204 2205 int 2206 ssh_packet_is_interactive(struct ssh *ssh) 2207 { 2208 return ssh->state->interactive_mode; 2209 } 2210 2211 int 2212 ssh_packet_set_maxsize(struct ssh *ssh, u_int s) 2213 { 2214 struct session_state *state = ssh->state; 2215 2216 if (state->set_maxsize_called) { 2217 logit_f("called twice: old %d new %d", 2218 state->max_packet_size, s); 2219 return -1; 2220 } 2221 if (s < 4 * 1024 || s > 1024 * 1024) { 2222 logit_f("bad size %d", s); 2223 return -1; 2224 } 2225 state->set_maxsize_called = 1; 2226 debug_f("setting to %d", s); 2227 state->max_packet_size = s; 2228 return s; 2229 } 2230 2231 int 2232 ssh_packet_inc_alive_timeouts(struct ssh *ssh) 2233 { 2234 return ++ssh->state->keep_alive_timeouts; 2235 } 2236 2237 void 2238 ssh_packet_set_alive_timeouts(struct ssh *ssh, int ka) 2239 { 2240 ssh->state->keep_alive_timeouts = ka; 2241 } 2242 2243 u_int 2244 ssh_packet_get_maxsize(struct ssh *ssh) 2245 { 2246 return ssh->state->max_packet_size; 2247 } 2248 2249 void 2250 ssh_packet_set_rekey_limits(struct ssh *ssh, u_int64_t bytes, u_int32_t seconds) 2251 { 2252 debug3("rekey after %llu bytes, %u seconds", (unsigned long long)bytes, 2253 (unsigned int)seconds); 2254 ssh->state->rekey_limit = bytes; 2255 ssh->state->rekey_interval = seconds; 2256 } 2257 2258 time_t 2259 ssh_packet_get_rekey_timeout(struct ssh *ssh) 2260 { 2261 time_t seconds; 2262 2263 seconds = ssh->state->rekey_time + ssh->state->rekey_interval - 2264 monotime(); 2265 return (seconds <= 0 ? 1 : seconds); 2266 } 2267 2268 void 2269 ssh_packet_set_server(struct ssh *ssh) 2270 { 2271 ssh->state->server_side = 1; 2272 ssh->kex->server = 1; /* XXX unify? */ 2273 } 2274 2275 void 2276 ssh_packet_set_authenticated(struct ssh *ssh) 2277 { 2278 ssh->state->after_authentication = 1; 2279 } 2280 2281 void * 2282 ssh_packet_get_input(struct ssh *ssh) 2283 { 2284 return (void *)ssh->state->input; 2285 } 2286 2287 void * 2288 ssh_packet_get_output(struct ssh *ssh) 2289 { 2290 return (void *)ssh->state->output; 2291 } 2292 2293 /* Reset after_authentication and reset compression in post-auth privsep */ 2294 static int 2295 ssh_packet_set_postauth(struct ssh *ssh) 2296 { 2297 int r; 2298 2299 debug_f("called"); 2300 /* This was set in net child, but is not visible in user child */ 2301 ssh->state->after_authentication = 1; 2302 ssh->state->rekeying = 0; 2303 if ((r = ssh_packet_enable_delayed_compress(ssh)) != 0) 2304 return r; 2305 return 0; 2306 } 2307 2308 /* Packet state (de-)serialization for privsep */ 2309 2310 /* turn kex into a blob for packet state serialization */ 2311 static int 2312 kex_to_blob(struct sshbuf *m, struct kex *kex) 2313 { 2314 int r; 2315 2316 if ((r = sshbuf_put_u32(m, kex->we_need)) != 0 || 2317 (r = sshbuf_put_cstring(m, kex->hostkey_alg)) != 0 || 2318 (r = sshbuf_put_u32(m, kex->hostkey_type)) != 0 || 2319 (r = sshbuf_put_u32(m, kex->hostkey_nid)) != 0 || 2320 (r = sshbuf_put_u32(m, kex->kex_type)) != 0 || 2321 (r = sshbuf_put_u32(m, kex->kex_strict)) != 0 || 2322 (r = sshbuf_put_stringb(m, kex->my)) != 0 || 2323 (r = sshbuf_put_stringb(m, kex->peer)) != 0 || 2324 (r = sshbuf_put_stringb(m, kex->client_version)) != 0 || 2325 (r = sshbuf_put_stringb(m, kex->server_version)) != 0 || 2326 (r = sshbuf_put_stringb(m, kex->session_id)) != 0 || 2327 (r = sshbuf_put_u32(m, kex->flags)) != 0) 2328 return r; 2329 return 0; 2330 } 2331 2332 /* turn key exchange results into a blob for packet state serialization */ 2333 static int 2334 newkeys_to_blob(struct sshbuf *m, struct ssh *ssh, int mode) 2335 { 2336 struct sshbuf *b; 2337 struct sshcipher_ctx *cc; 2338 struct sshcomp *comp; 2339 struct sshenc *enc; 2340 struct sshmac *mac; 2341 struct newkeys *newkey; 2342 int r; 2343 2344 if ((newkey = ssh->state->newkeys[mode]) == NULL) 2345 return SSH_ERR_INTERNAL_ERROR; 2346 enc = &newkey->enc; 2347 mac = &newkey->mac; 2348 comp = &newkey->comp; 2349 cc = (mode == MODE_OUT) ? ssh->state->send_context : 2350 ssh->state->receive_context; 2351 if ((r = cipher_get_keyiv(cc, enc->iv, enc->iv_len)) != 0) 2352 return r; 2353 if ((b = sshbuf_new()) == NULL) 2354 return SSH_ERR_ALLOC_FAIL; 2355 if ((r = sshbuf_put_cstring(b, enc->name)) != 0 || 2356 (r = sshbuf_put_u32(b, enc->enabled)) != 0 || 2357 (r = sshbuf_put_u32(b, enc->block_size)) != 0 || 2358 (r = sshbuf_put_string(b, enc->key, enc->key_len)) != 0 || 2359 (r = sshbuf_put_string(b, enc->iv, enc->iv_len)) != 0) 2360 goto out; 2361 if (cipher_authlen(enc->cipher) == 0) { 2362 if ((r = sshbuf_put_cstring(b, mac->name)) != 0 || 2363 (r = sshbuf_put_u32(b, mac->enabled)) != 0 || 2364 (r = sshbuf_put_string(b, mac->key, mac->key_len)) != 0) 2365 goto out; 2366 } 2367 if ((r = sshbuf_put_u32(b, comp->type)) != 0 || 2368 (r = sshbuf_put_cstring(b, comp->name)) != 0) 2369 goto out; 2370 r = sshbuf_put_stringb(m, b); 2371 out: 2372 sshbuf_free(b); 2373 return r; 2374 } 2375 2376 /* serialize packet state into a blob */ 2377 int 2378 ssh_packet_get_state(struct ssh *ssh, struct sshbuf *m) 2379 { 2380 struct session_state *state = ssh->state; 2381 int r; 2382 2383 if ((r = kex_to_blob(m, ssh->kex)) != 0 || 2384 (r = newkeys_to_blob(m, ssh, MODE_OUT)) != 0 || 2385 (r = newkeys_to_blob(m, ssh, MODE_IN)) != 0 || 2386 (r = sshbuf_put_u64(m, state->rekey_limit)) != 0 || 2387 (r = sshbuf_put_u32(m, state->rekey_interval)) != 0 || 2388 (r = sshbuf_put_u32(m, state->p_send.seqnr)) != 0 || 2389 (r = sshbuf_put_u64(m, state->p_send.blocks)) != 0 || 2390 (r = sshbuf_put_u32(m, state->p_send.packets)) != 0 || 2391 (r = sshbuf_put_u64(m, state->p_send.bytes)) != 0 || 2392 (r = sshbuf_put_u32(m, state->p_read.seqnr)) != 0 || 2393 (r = sshbuf_put_u64(m, state->p_read.blocks)) != 0 || 2394 (r = sshbuf_put_u32(m, state->p_read.packets)) != 0 || 2395 (r = sshbuf_put_u64(m, state->p_read.bytes)) != 0 || 2396 (r = sshbuf_put_stringb(m, state->input)) != 0 || 2397 (r = sshbuf_put_stringb(m, state->output)) != 0) 2398 return r; 2399 2400 return 0; 2401 } 2402 2403 /* restore key exchange results from blob for packet state de-serialization */ 2404 static int 2405 newkeys_from_blob(struct sshbuf *m, struct ssh *ssh, int mode) 2406 { 2407 struct sshbuf *b = NULL; 2408 struct sshcomp *comp; 2409 struct sshenc *enc; 2410 struct sshmac *mac; 2411 struct newkeys *newkey = NULL; 2412 size_t keylen, ivlen, maclen; 2413 int r; 2414 2415 if ((newkey = calloc(1, sizeof(*newkey))) == NULL) { 2416 r = SSH_ERR_ALLOC_FAIL; 2417 goto out; 2418 } 2419 if ((r = sshbuf_froms(m, &b)) != 0) 2420 goto out; 2421 #ifdef DEBUG_PK 2422 sshbuf_dump(b, stderr); 2423 #endif 2424 enc = &newkey->enc; 2425 mac = &newkey->mac; 2426 comp = &newkey->comp; 2427 2428 if ((r = sshbuf_get_cstring(b, &enc->name, NULL)) != 0 || 2429 (r = sshbuf_get_u32(b, (u_int *)&enc->enabled)) != 0 || 2430 (r = sshbuf_get_u32(b, &enc->block_size)) != 0 || 2431 (r = sshbuf_get_string(b, &enc->key, &keylen)) != 0 || 2432 (r = sshbuf_get_string(b, &enc->iv, &ivlen)) != 0) 2433 goto out; 2434 if ((enc->cipher = cipher_by_name(enc->name)) == NULL) { 2435 r = SSH_ERR_INVALID_FORMAT; 2436 goto out; 2437 } 2438 if (cipher_authlen(enc->cipher) == 0) { 2439 if ((r = sshbuf_get_cstring(b, &mac->name, NULL)) != 0) 2440 goto out; 2441 if ((r = mac_setup(mac, mac->name)) != 0) 2442 goto out; 2443 if ((r = sshbuf_get_u32(b, (u_int *)&mac->enabled)) != 0 || 2444 (r = sshbuf_get_string(b, &mac->key, &maclen)) != 0) 2445 goto out; 2446 if (maclen > mac->key_len) { 2447 r = SSH_ERR_INVALID_FORMAT; 2448 goto out; 2449 } 2450 mac->key_len = maclen; 2451 } 2452 if ((r = sshbuf_get_u32(b, &comp->type)) != 0 || 2453 (r = sshbuf_get_cstring(b, &comp->name, NULL)) != 0) 2454 goto out; 2455 if (sshbuf_len(b) != 0) { 2456 r = SSH_ERR_INVALID_FORMAT; 2457 goto out; 2458 } 2459 enc->key_len = keylen; 2460 enc->iv_len = ivlen; 2461 ssh->kex->newkeys[mode] = newkey; 2462 newkey = NULL; 2463 r = 0; 2464 out: 2465 free(newkey); 2466 sshbuf_free(b); 2467 return r; 2468 } 2469 2470 /* restore kex from blob for packet state de-serialization */ 2471 static int 2472 kex_from_blob(struct sshbuf *m, struct kex **kexp) 2473 { 2474 struct kex *kex; 2475 int r; 2476 2477 if ((kex = kex_new()) == NULL) 2478 return SSH_ERR_ALLOC_FAIL; 2479 if ((r = sshbuf_get_u32(m, &kex->we_need)) != 0 || 2480 (r = sshbuf_get_cstring(m, &kex->hostkey_alg, NULL)) != 0 || 2481 (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_type)) != 0 || 2482 (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_nid)) != 0 || 2483 (r = sshbuf_get_u32(m, &kex->kex_type)) != 0 || 2484 (r = sshbuf_get_u32(m, &kex->kex_strict)) != 0 || 2485 (r = sshbuf_get_stringb(m, kex->my)) != 0 || 2486 (r = sshbuf_get_stringb(m, kex->peer)) != 0 || 2487 (r = sshbuf_get_stringb(m, kex->client_version)) != 0 || 2488 (r = sshbuf_get_stringb(m, kex->server_version)) != 0 || 2489 (r = sshbuf_get_stringb(m, kex->session_id)) != 0 || 2490 (r = sshbuf_get_u32(m, &kex->flags)) != 0) 2491 goto out; 2492 kex->server = 1; 2493 kex->done = 1; 2494 r = 0; 2495 out: 2496 if (r != 0 || kexp == NULL) { 2497 kex_free(kex); 2498 if (kexp != NULL) 2499 *kexp = NULL; 2500 } else { 2501 kex_free(*kexp); 2502 *kexp = kex; 2503 } 2504 return r; 2505 } 2506 2507 /* 2508 * Restore packet state from content of blob 'm' (de-serialization). 2509 * Note that 'm' will be partially consumed on parsing or any other errors. 2510 */ 2511 int 2512 ssh_packet_set_state(struct ssh *ssh, struct sshbuf *m) 2513 { 2514 struct session_state *state = ssh->state; 2515 const u_char *input, *output; 2516 size_t ilen, olen; 2517 int r; 2518 2519 if ((r = kex_from_blob(m, &ssh->kex)) != 0 || 2520 (r = newkeys_from_blob(m, ssh, MODE_OUT)) != 0 || 2521 (r = newkeys_from_blob(m, ssh, MODE_IN)) != 0 || 2522 (r = sshbuf_get_u64(m, &state->rekey_limit)) != 0 || 2523 (r = sshbuf_get_u32(m, &state->rekey_interval)) != 0 || 2524 (r = sshbuf_get_u32(m, &state->p_send.seqnr)) != 0 || 2525 (r = sshbuf_get_u64(m, &state->p_send.blocks)) != 0 || 2526 (r = sshbuf_get_u32(m, &state->p_send.packets)) != 0 || 2527 (r = sshbuf_get_u64(m, &state->p_send.bytes)) != 0 || 2528 (r = sshbuf_get_u32(m, &state->p_read.seqnr)) != 0 || 2529 (r = sshbuf_get_u64(m, &state->p_read.blocks)) != 0 || 2530 (r = sshbuf_get_u32(m, &state->p_read.packets)) != 0 || 2531 (r = sshbuf_get_u64(m, &state->p_read.bytes)) != 0) 2532 return r; 2533 /* 2534 * We set the time here so that in post-auth privsep child we 2535 * count from the completion of the authentication. 2536 */ 2537 state->rekey_time = monotime(); 2538 /* XXX ssh_set_newkeys overrides p_read.packets? XXX */ 2539 if ((r = ssh_set_newkeys(ssh, MODE_IN)) != 0 || 2540 (r = ssh_set_newkeys(ssh, MODE_OUT)) != 0) 2541 return r; 2542 2543 if ((r = ssh_packet_set_postauth(ssh)) != 0) 2544 return r; 2545 2546 sshbuf_reset(state->input); 2547 sshbuf_reset(state->output); 2548 if ((r = sshbuf_get_string_direct(m, &input, &ilen)) != 0 || 2549 (r = sshbuf_get_string_direct(m, &output, &olen)) != 0 || 2550 (r = sshbuf_put(state->input, input, ilen)) != 0 || 2551 (r = sshbuf_put(state->output, output, olen)) != 0) 2552 return r; 2553 2554 if (sshbuf_len(m)) 2555 return SSH_ERR_INVALID_FORMAT; 2556 debug3_f("done"); 2557 return 0; 2558 } 2559 2560 /* NEW API */ 2561 2562 /* put data to the outgoing packet */ 2563 2564 int 2565 sshpkt_put(struct ssh *ssh, const void *v, size_t len) 2566 { 2567 return sshbuf_put(ssh->state->outgoing_packet, v, len); 2568 } 2569 2570 int 2571 sshpkt_putb(struct ssh *ssh, const struct sshbuf *b) 2572 { 2573 return sshbuf_putb(ssh->state->outgoing_packet, b); 2574 } 2575 2576 int 2577 sshpkt_put_u8(struct ssh *ssh, u_char val) 2578 { 2579 return sshbuf_put_u8(ssh->state->outgoing_packet, val); 2580 } 2581 2582 int 2583 sshpkt_put_u32(struct ssh *ssh, u_int32_t val) 2584 { 2585 return sshbuf_put_u32(ssh->state->outgoing_packet, val); 2586 } 2587 2588 int 2589 sshpkt_put_u64(struct ssh *ssh, u_int64_t val) 2590 { 2591 return sshbuf_put_u64(ssh->state->outgoing_packet, val); 2592 } 2593 2594 int 2595 sshpkt_put_string(struct ssh *ssh, const void *v, size_t len) 2596 { 2597 return sshbuf_put_string(ssh->state->outgoing_packet, v, len); 2598 } 2599 2600 int 2601 sshpkt_put_cstring(struct ssh *ssh, const void *v) 2602 { 2603 return sshbuf_put_cstring(ssh->state->outgoing_packet, v); 2604 } 2605 2606 int 2607 sshpkt_put_stringb(struct ssh *ssh, const struct sshbuf *v) 2608 { 2609 return sshbuf_put_stringb(ssh->state->outgoing_packet, v); 2610 } 2611 2612 #ifdef WITH_OPENSSL 2613 int 2614 sshpkt_put_ec(struct ssh *ssh, const EC_POINT *v, const EC_GROUP *g) 2615 { 2616 return sshbuf_put_ec(ssh->state->outgoing_packet, v, g); 2617 } 2618 2619 int 2620 sshpkt_put_ec_pkey(struct ssh *ssh, EVP_PKEY *pkey) 2621 { 2622 return sshbuf_put_ec_pkey(ssh->state->outgoing_packet, pkey); 2623 } 2624 2625 int 2626 sshpkt_put_bignum2(struct ssh *ssh, const BIGNUM *v) 2627 { 2628 return sshbuf_put_bignum2(ssh->state->outgoing_packet, v); 2629 } 2630 #endif /* WITH_OPENSSL */ 2631 2632 /* fetch data from the incoming packet */ 2633 2634 int 2635 sshpkt_get(struct ssh *ssh, void *valp, size_t len) 2636 { 2637 return sshbuf_get(ssh->state->incoming_packet, valp, len); 2638 } 2639 2640 int 2641 sshpkt_get_u8(struct ssh *ssh, u_char *valp) 2642 { 2643 return sshbuf_get_u8(ssh->state->incoming_packet, valp); 2644 } 2645 2646 int 2647 sshpkt_get_u32(struct ssh *ssh, u_int32_t *valp) 2648 { 2649 return sshbuf_get_u32(ssh->state->incoming_packet, valp); 2650 } 2651 2652 int 2653 sshpkt_get_u64(struct ssh *ssh, u_int64_t *valp) 2654 { 2655 return sshbuf_get_u64(ssh->state->incoming_packet, valp); 2656 } 2657 2658 int 2659 sshpkt_get_string(struct ssh *ssh, u_char **valp, size_t *lenp) 2660 { 2661 return sshbuf_get_string(ssh->state->incoming_packet, valp, lenp); 2662 } 2663 2664 int 2665 sshpkt_get_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp) 2666 { 2667 return sshbuf_get_string_direct(ssh->state->incoming_packet, valp, lenp); 2668 } 2669 2670 int 2671 sshpkt_peek_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp) 2672 { 2673 return sshbuf_peek_string_direct(ssh->state->incoming_packet, valp, lenp); 2674 } 2675 2676 int 2677 sshpkt_get_cstring(struct ssh *ssh, char **valp, size_t *lenp) 2678 { 2679 return sshbuf_get_cstring(ssh->state->incoming_packet, valp, lenp); 2680 } 2681 2682 int 2683 sshpkt_getb_froms(struct ssh *ssh, struct sshbuf **valp) 2684 { 2685 return sshbuf_froms(ssh->state->incoming_packet, valp); 2686 } 2687 2688 #ifdef WITH_OPENSSL 2689 int 2690 sshpkt_get_ec(struct ssh *ssh, EC_POINT *v, const EC_GROUP *g) 2691 { 2692 return sshbuf_get_ec(ssh->state->incoming_packet, v, g); 2693 } 2694 2695 int 2696 sshpkt_get_bignum2(struct ssh *ssh, BIGNUM **valp) 2697 { 2698 return sshbuf_get_bignum2(ssh->state->incoming_packet, valp); 2699 } 2700 #endif /* WITH_OPENSSL */ 2701 2702 int 2703 sshpkt_get_end(struct ssh *ssh) 2704 { 2705 if (sshbuf_len(ssh->state->incoming_packet) > 0) 2706 return SSH_ERR_UNEXPECTED_TRAILING_DATA; 2707 return 0; 2708 } 2709 2710 const u_char * 2711 sshpkt_ptr(struct ssh *ssh, size_t *lenp) 2712 { 2713 if (lenp != NULL) 2714 *lenp = sshbuf_len(ssh->state->incoming_packet); 2715 return sshbuf_ptr(ssh->state->incoming_packet); 2716 } 2717 2718 /* start a new packet */ 2719 2720 int 2721 sshpkt_start(struct ssh *ssh, u_char type) 2722 { 2723 u_char buf[6]; /* u32 packet length, u8 pad len, u8 type */ 2724 2725 DBG(debug("packet_start[%d]", type)); 2726 memset(buf, 0, sizeof(buf)); 2727 buf[sizeof(buf) - 1] = type; 2728 sshbuf_reset(ssh->state->outgoing_packet); 2729 return sshbuf_put(ssh->state->outgoing_packet, buf, sizeof(buf)); 2730 } 2731 2732 static int 2733 ssh_packet_send_mux(struct ssh *ssh) 2734 { 2735 struct session_state *state = ssh->state; 2736 u_char type, *cp; 2737 size_t len; 2738 int r; 2739 2740 if (ssh->kex) 2741 return SSH_ERR_INTERNAL_ERROR; 2742 len = sshbuf_len(state->outgoing_packet); 2743 if (len < 6) 2744 return SSH_ERR_INTERNAL_ERROR; 2745 cp = sshbuf_mutable_ptr(state->outgoing_packet); 2746 type = cp[5]; 2747 if (ssh_packet_log_type(type)) 2748 debug3_f("type %u", type); 2749 /* drop everything, but the connection protocol */ 2750 if (type >= SSH2_MSG_CONNECTION_MIN && 2751 type <= SSH2_MSG_CONNECTION_MAX) { 2752 POKE_U32(cp, len - 4); 2753 if ((r = sshbuf_putb(state->output, 2754 state->outgoing_packet)) != 0) 2755 return r; 2756 /* sshbuf_dump(state->output, stderr); */ 2757 } 2758 sshbuf_reset(state->outgoing_packet); 2759 return 0; 2760 } 2761 2762 /* 2763 * 9.2. Ignored Data Message 2764 * 2765 * byte SSH_MSG_IGNORE 2766 * string data 2767 * 2768 * All implementations MUST understand (and ignore) this message at any 2769 * time (after receiving the protocol version). No implementation is 2770 * required to send them. This message can be used as an additional 2771 * protection measure against advanced traffic analysis techniques. 2772 */ 2773 int 2774 sshpkt_msg_ignore(struct ssh *ssh, u_int nbytes) 2775 { 2776 u_int32_t rnd = 0; 2777 int r; 2778 u_int i; 2779 2780 if ((r = sshpkt_start(ssh, SSH2_MSG_IGNORE)) != 0 || 2781 (r = sshpkt_put_u32(ssh, nbytes)) != 0) 2782 return r; 2783 for (i = 0; i < nbytes; i++) { 2784 if (i % 4 == 0) 2785 rnd = arc4random(); 2786 if ((r = sshpkt_put_u8(ssh, (u_char)rnd & 0xff)) != 0) 2787 return r; 2788 rnd >>= 8; 2789 } 2790 return 0; 2791 } 2792 2793 /* send it */ 2794 2795 int 2796 sshpkt_send(struct ssh *ssh) 2797 { 2798 if (ssh->state && ssh->state->mux) 2799 return ssh_packet_send_mux(ssh); 2800 return ssh_packet_send2(ssh); 2801 } 2802 2803 int 2804 sshpkt_disconnect(struct ssh *ssh, const char *fmt,...) 2805 { 2806 char buf[1024]; 2807 va_list args; 2808 int r; 2809 2810 va_start(args, fmt); 2811 vsnprintf(buf, sizeof(buf), fmt, args); 2812 va_end(args); 2813 2814 debug2_f("sending SSH2_MSG_DISCONNECT: %s", buf); 2815 if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 || 2816 (r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_PROTOCOL_ERROR)) != 0 || 2817 (r = sshpkt_put_cstring(ssh, buf)) != 0 || 2818 (r = sshpkt_put_cstring(ssh, "")) != 0 || 2819 (r = sshpkt_send(ssh)) != 0) 2820 return r; 2821 return 0; 2822 } 2823 2824 /* roundup current message to pad bytes */ 2825 int 2826 sshpkt_add_padding(struct ssh *ssh, u_char pad) 2827 { 2828 ssh->state->extra_pad = pad; 2829 return 0; 2830 } 2831