packet.c revision 295367
1/* $OpenBSD: packet.c,v 1.214 2015/08/20 22:32:42 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 "includes.h" 41__RCSID("$FreeBSD: stable/10/crypto/openssh/packet.c 295367 2016-02-07 11:38:54Z des $"); 42 43#include <sys/param.h> /* MIN roundup */ 44#include <sys/types.h> 45#include "openbsd-compat/sys-queue.h" 46#include <sys/socket.h> 47#ifdef HAVE_SYS_TIME_H 48# include <sys/time.h> 49#endif 50 51#include <netinet/in.h> 52#include <netinet/ip.h> 53#include <arpa/inet.h> 54 55#include <errno.h> 56#include <stdarg.h> 57#include <stdio.h> 58#include <stdlib.h> 59#include <string.h> 60#include <unistd.h> 61#include <limits.h> 62#include <signal.h> 63#include <time.h> 64 65#include <zlib.h> 66 67#include "buffer.h" /* typedefs XXX */ 68#include "key.h" /* typedefs XXX */ 69 70#include "xmalloc.h" 71#include "crc32.h" 72#include "deattack.h" 73#include "compat.h" 74#include "ssh1.h" 75#include "ssh2.h" 76#include "cipher.h" 77#include "sshkey.h" 78#include "kex.h" 79#include "digest.h" 80#include "mac.h" 81#include "log.h" 82#include "canohost.h" 83#include "misc.h" 84#include "channels.h" 85#include "ssh.h" 86#include "packet.h" 87#include "roaming.h" 88#include "ssherr.h" 89#include "sshbuf.h" 90 91#ifdef PACKET_DEBUG 92#define DBG(x) x 93#else 94#define DBG(x) 95#endif 96 97#define PACKET_MAX_SIZE (256 * 1024) 98 99struct packet_state { 100 u_int32_t seqnr; 101 u_int32_t packets; 102 u_int64_t blocks; 103 u_int64_t bytes; 104}; 105 106struct packet { 107 TAILQ_ENTRY(packet) next; 108 u_char type; 109 struct sshbuf *payload; 110}; 111 112struct session_state { 113 /* 114 * This variable contains the file descriptors used for 115 * communicating with the other side. connection_in is used for 116 * reading; connection_out for writing. These can be the same 117 * descriptor, in which case it is assumed to be a socket. 118 */ 119 int connection_in; 120 int connection_out; 121 122 /* Protocol flags for the remote side. */ 123 u_int remote_protocol_flags; 124 125 /* Encryption context for receiving data. Only used for decryption. */ 126 struct sshcipher_ctx receive_context; 127 128 /* Encryption context for sending data. Only used for encryption. */ 129 struct sshcipher_ctx send_context; 130 131 /* Buffer for raw input data from the socket. */ 132 struct sshbuf *input; 133 134 /* Buffer for raw output data going to the socket. */ 135 struct sshbuf *output; 136 137 /* Buffer for the partial outgoing packet being constructed. */ 138 struct sshbuf *outgoing_packet; 139 140 /* Buffer for the incoming packet currently being processed. */ 141 struct sshbuf *incoming_packet; 142 143 /* Scratch buffer for packet compression/decompression. */ 144 struct sshbuf *compression_buffer; 145 146 /* Incoming/outgoing compression dictionaries */ 147 z_stream compression_in_stream; 148 z_stream compression_out_stream; 149 int compression_in_started; 150 int compression_out_started; 151 int compression_in_failures; 152 int compression_out_failures; 153 154 /* 155 * Flag indicating whether packet compression/decompression is 156 * enabled. 157 */ 158 int packet_compression; 159 160 /* default maximum packet size */ 161 u_int max_packet_size; 162 163 /* Flag indicating whether this module has been initialized. */ 164 int initialized; 165 166 /* Set to true if the connection is interactive. */ 167 int interactive_mode; 168 169 /* Set to true if we are the server side. */ 170 int server_side; 171 172 /* Set to true if we are authenticated. */ 173 int after_authentication; 174 175 int keep_alive_timeouts; 176 177 /* The maximum time that we will wait to send or receive a packet */ 178 int packet_timeout_ms; 179 180 /* Session key information for Encryption and MAC */ 181 struct newkeys *newkeys[MODE_MAX]; 182 struct packet_state p_read, p_send; 183 184 /* Volume-based rekeying */ 185 u_int64_t max_blocks_in, max_blocks_out; 186 u_int32_t rekey_limit; 187 188 /* Time-based rekeying */ 189 u_int32_t rekey_interval; /* how often in seconds */ 190 time_t rekey_time; /* time of last rekeying */ 191 192 /* Session key for protocol v1 */ 193 u_char ssh1_key[SSH_SESSION_KEY_LENGTH]; 194 u_int ssh1_keylen; 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 struct sshmac *packet_discard_mac; 202 203 /* Used in packet_read_poll2() */ 204 u_int packlen; 205 206 /* Used in packet_send2 */ 207 int rekeying; 208 209 /* Used in packet_set_interactive */ 210 int set_interactive_called; 211 212 /* Used in packet_set_maxsize */ 213 int set_maxsize_called; 214 215 /* One-off warning about weak ciphers */ 216 int cipher_warning_done; 217 218 /* SSH1 CRC compensation attack detector */ 219 struct deattack_ctx deattack; 220 221 TAILQ_HEAD(, packet) outgoing; 222}; 223 224struct ssh * 225ssh_alloc_session_state(void) 226{ 227 struct ssh *ssh = NULL; 228 struct session_state *state = NULL; 229 230 if ((ssh = calloc(1, sizeof(*ssh))) == NULL || 231 (state = calloc(1, sizeof(*state))) == NULL || 232 (state->input = sshbuf_new()) == NULL || 233 (state->output = sshbuf_new()) == NULL || 234 (state->outgoing_packet = sshbuf_new()) == NULL || 235 (state->incoming_packet = sshbuf_new()) == NULL) 236 goto fail; 237 TAILQ_INIT(&state->outgoing); 238 TAILQ_INIT(&ssh->private_keys); 239 TAILQ_INIT(&ssh->public_keys); 240 state->connection_in = -1; 241 state->connection_out = -1; 242 state->max_packet_size = 32768; 243 state->packet_timeout_ms = -1; 244 state->p_send.packets = state->p_read.packets = 0; 245 state->initialized = 1; 246 /* 247 * ssh_packet_send2() needs to queue packets until 248 * we've done the initial key exchange. 249 */ 250 state->rekeying = 1; 251 ssh->state = state; 252 return ssh; 253 fail: 254 if (state) { 255 sshbuf_free(state->input); 256 sshbuf_free(state->output); 257 sshbuf_free(state->incoming_packet); 258 sshbuf_free(state->outgoing_packet); 259 free(state); 260 } 261 free(ssh); 262 return NULL; 263} 264 265/* 266 * Sets the descriptors used for communication. Disables encryption until 267 * packet_set_encryption_key is called. 268 */ 269struct ssh * 270ssh_packet_set_connection(struct ssh *ssh, int fd_in, int fd_out) 271{ 272 struct session_state *state; 273 const struct sshcipher *none = cipher_by_name("none"); 274 int r; 275 276 if (none == NULL) { 277 error("%s: cannot load cipher 'none'", __func__); 278 return NULL; 279 } 280 if (ssh == NULL) 281 ssh = ssh_alloc_session_state(); 282 if (ssh == NULL) { 283 error("%s: cound not allocate state", __func__); 284 return NULL; 285 } 286 state = ssh->state; 287 state->connection_in = fd_in; 288 state->connection_out = fd_out; 289 if ((r = cipher_init(&state->send_context, none, 290 (const u_char *)"", 0, NULL, 0, CIPHER_ENCRYPT)) != 0 || 291 (r = cipher_init(&state->receive_context, none, 292 (const u_char *)"", 0, NULL, 0, CIPHER_DECRYPT)) != 0) { 293 error("%s: cipher_init failed: %s", __func__, ssh_err(r)); 294 free(ssh); 295 return NULL; 296 } 297 state->newkeys[MODE_IN] = state->newkeys[MODE_OUT] = NULL; 298 deattack_init(&state->deattack); 299 /* 300 * Cache the IP address of the remote connection for use in error 301 * messages that might be generated after the connection has closed. 302 */ 303 (void)ssh_remote_ipaddr(ssh); 304 return ssh; 305} 306 307void 308ssh_packet_set_timeout(struct ssh *ssh, int timeout, int count) 309{ 310 struct session_state *state = ssh->state; 311 312 if (timeout <= 0 || count <= 0) { 313 state->packet_timeout_ms = -1; 314 return; 315 } 316 if ((INT_MAX / 1000) / count < timeout) 317 state->packet_timeout_ms = INT_MAX; 318 else 319 state->packet_timeout_ms = timeout * count * 1000; 320} 321 322int 323ssh_packet_stop_discard(struct ssh *ssh) 324{ 325 struct session_state *state = ssh->state; 326 int r; 327 328 if (state->packet_discard_mac) { 329 char buf[1024]; 330 331 memset(buf, 'a', sizeof(buf)); 332 while (sshbuf_len(state->incoming_packet) < 333 PACKET_MAX_SIZE) 334 if ((r = sshbuf_put(state->incoming_packet, buf, 335 sizeof(buf))) != 0) 336 return r; 337 (void) mac_compute(state->packet_discard_mac, 338 state->p_read.seqnr, 339 sshbuf_ptr(state->incoming_packet), PACKET_MAX_SIZE, 340 NULL, 0); 341 } 342 logit("Finished discarding for %.200s", ssh_remote_ipaddr(ssh)); 343 return SSH_ERR_MAC_INVALID; 344} 345 346static int 347ssh_packet_start_discard(struct ssh *ssh, struct sshenc *enc, 348 struct sshmac *mac, u_int packet_length, u_int discard) 349{ 350 struct session_state *state = ssh->state; 351 int r; 352 353 if (enc == NULL || !cipher_is_cbc(enc->cipher) || (mac && mac->etm)) { 354 if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0) 355 return r; 356 return SSH_ERR_MAC_INVALID; 357 } 358 if (packet_length != PACKET_MAX_SIZE && mac && mac->enabled) 359 state->packet_discard_mac = mac; 360 if (sshbuf_len(state->input) >= discard && 361 (r = ssh_packet_stop_discard(ssh)) != 0) 362 return r; 363 state->packet_discard = discard - sshbuf_len(state->input); 364 return 0; 365} 366 367/* Returns 1 if remote host is connected via socket, 0 if not. */ 368 369int 370ssh_packet_connection_is_on_socket(struct ssh *ssh) 371{ 372 struct session_state *state = ssh->state; 373 struct sockaddr_storage from, to; 374 socklen_t fromlen, tolen; 375 376 /* filedescriptors in and out are the same, so it's a socket */ 377 if (state->connection_in == state->connection_out) 378 return 1; 379 fromlen = sizeof(from); 380 memset(&from, 0, sizeof(from)); 381 if (getpeername(state->connection_in, (struct sockaddr *)&from, 382 &fromlen) < 0) 383 return 0; 384 tolen = sizeof(to); 385 memset(&to, 0, sizeof(to)); 386 if (getpeername(state->connection_out, (struct sockaddr *)&to, 387 &tolen) < 0) 388 return 0; 389 if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0) 390 return 0; 391 if (from.ss_family != AF_INET && from.ss_family != AF_INET6) 392 return 0; 393 return 1; 394} 395 396void 397ssh_packet_get_bytes(struct ssh *ssh, u_int64_t *ibytes, u_int64_t *obytes) 398{ 399 if (ibytes) 400 *ibytes = ssh->state->p_read.bytes; 401 if (obytes) 402 *obytes = ssh->state->p_send.bytes; 403} 404 405int 406ssh_packet_connection_af(struct ssh *ssh) 407{ 408 struct sockaddr_storage to; 409 socklen_t tolen = sizeof(to); 410 411 memset(&to, 0, sizeof(to)); 412 if (getsockname(ssh->state->connection_out, (struct sockaddr *)&to, 413 &tolen) < 0) 414 return 0; 415#ifdef IPV4_IN_IPV6 416 if (to.ss_family == AF_INET6 && 417 IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&to)->sin6_addr)) 418 return AF_INET; 419#endif 420 return to.ss_family; 421} 422 423/* Sets the connection into non-blocking mode. */ 424 425void 426ssh_packet_set_nonblocking(struct ssh *ssh) 427{ 428 /* Set the socket into non-blocking mode. */ 429 set_nonblock(ssh->state->connection_in); 430 431 if (ssh->state->connection_out != ssh->state->connection_in) 432 set_nonblock(ssh->state->connection_out); 433} 434 435/* Returns the socket used for reading. */ 436 437int 438ssh_packet_get_connection_in(struct ssh *ssh) 439{ 440 return ssh->state->connection_in; 441} 442 443/* Returns the descriptor used for writing. */ 444 445int 446ssh_packet_get_connection_out(struct ssh *ssh) 447{ 448 return ssh->state->connection_out; 449} 450 451/* 452 * Returns the IP-address of the remote host as a string. The returned 453 * string must not be freed. 454 */ 455 456const char * 457ssh_remote_ipaddr(struct ssh *ssh) 458{ 459 /* Check whether we have cached the ipaddr. */ 460 if (ssh->remote_ipaddr == NULL) 461 ssh->remote_ipaddr = ssh_packet_connection_is_on_socket(ssh) ? 462 get_peer_ipaddr(ssh->state->connection_in) : 463 strdup("UNKNOWN"); 464 if (ssh->remote_ipaddr == NULL) 465 return "UNKNOWN"; 466 return ssh->remote_ipaddr; 467} 468 469/* Closes the connection and clears and frees internal data structures. */ 470 471void 472ssh_packet_close(struct ssh *ssh) 473{ 474 struct session_state *state = ssh->state; 475 int r; 476 u_int mode; 477 478 if (!state->initialized) 479 return; 480 state->initialized = 0; 481 if (state->connection_in == state->connection_out) { 482 shutdown(state->connection_out, SHUT_RDWR); 483 close(state->connection_out); 484 } else { 485 close(state->connection_in); 486 close(state->connection_out); 487 } 488 sshbuf_free(state->input); 489 sshbuf_free(state->output); 490 sshbuf_free(state->outgoing_packet); 491 sshbuf_free(state->incoming_packet); 492 for (mode = 0; mode < MODE_MAX; mode++) 493 kex_free_newkeys(state->newkeys[mode]); 494 if (state->compression_buffer) { 495 sshbuf_free(state->compression_buffer); 496 if (state->compression_out_started) { 497 z_streamp stream = &state->compression_out_stream; 498 debug("compress outgoing: " 499 "raw data %llu, compressed %llu, factor %.2f", 500 (unsigned long long)stream->total_in, 501 (unsigned long long)stream->total_out, 502 stream->total_in == 0 ? 0.0 : 503 (double) stream->total_out / stream->total_in); 504 if (state->compression_out_failures == 0) 505 deflateEnd(stream); 506 } 507 if (state->compression_in_started) { 508 z_streamp stream = &state->compression_out_stream; 509 debug("compress incoming: " 510 "raw data %llu, compressed %llu, factor %.2f", 511 (unsigned long long)stream->total_out, 512 (unsigned long long)stream->total_in, 513 stream->total_out == 0 ? 0.0 : 514 (double) stream->total_in / stream->total_out); 515 if (state->compression_in_failures == 0) 516 inflateEnd(stream); 517 } 518 } 519 if ((r = cipher_cleanup(&state->send_context)) != 0) 520 error("%s: cipher_cleanup failed: %s", __func__, ssh_err(r)); 521 if ((r = cipher_cleanup(&state->receive_context)) != 0) 522 error("%s: cipher_cleanup failed: %s", __func__, ssh_err(r)); 523 if (ssh->remote_ipaddr) { 524 free(ssh->remote_ipaddr); 525 ssh->remote_ipaddr = NULL; 526 } 527 free(ssh->state); 528 ssh->state = NULL; 529} 530 531/* Sets remote side protocol flags. */ 532 533void 534ssh_packet_set_protocol_flags(struct ssh *ssh, u_int protocol_flags) 535{ 536 ssh->state->remote_protocol_flags = protocol_flags; 537} 538 539/* Returns the remote protocol flags set earlier by the above function. */ 540 541u_int 542ssh_packet_get_protocol_flags(struct ssh *ssh) 543{ 544 return ssh->state->remote_protocol_flags; 545} 546 547/* 548 * Starts packet compression from the next packet on in both directions. 549 * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip. 550 */ 551 552static int 553ssh_packet_init_compression(struct ssh *ssh) 554{ 555 if (!ssh->state->compression_buffer && 556 ((ssh->state->compression_buffer = sshbuf_new()) == NULL)) 557 return SSH_ERR_ALLOC_FAIL; 558 return 0; 559} 560 561static int 562start_compression_out(struct ssh *ssh, int level) 563{ 564 if (level < 1 || level > 9) 565 return SSH_ERR_INVALID_ARGUMENT; 566 debug("Enabling compression at level %d.", level); 567 if (ssh->state->compression_out_started == 1) 568 deflateEnd(&ssh->state->compression_out_stream); 569 switch (deflateInit(&ssh->state->compression_out_stream, level)) { 570 case Z_OK: 571 ssh->state->compression_out_started = 1; 572 break; 573 case Z_MEM_ERROR: 574 return SSH_ERR_ALLOC_FAIL; 575 default: 576 return SSH_ERR_INTERNAL_ERROR; 577 } 578 return 0; 579} 580 581static int 582start_compression_in(struct ssh *ssh) 583{ 584 if (ssh->state->compression_in_started == 1) 585 inflateEnd(&ssh->state->compression_in_stream); 586 switch (inflateInit(&ssh->state->compression_in_stream)) { 587 case Z_OK: 588 ssh->state->compression_in_started = 1; 589 break; 590 case Z_MEM_ERROR: 591 return SSH_ERR_ALLOC_FAIL; 592 default: 593 return SSH_ERR_INTERNAL_ERROR; 594 } 595 return 0; 596} 597 598int 599ssh_packet_start_compression(struct ssh *ssh, int level) 600{ 601 int r; 602 603 if (ssh->state->packet_compression && !compat20) 604 return SSH_ERR_INTERNAL_ERROR; 605 ssh->state->packet_compression = 1; 606 if ((r = ssh_packet_init_compression(ssh)) != 0 || 607 (r = start_compression_in(ssh)) != 0 || 608 (r = start_compression_out(ssh, level)) != 0) 609 return r; 610 return 0; 611} 612 613/* XXX remove need for separate compression buffer */ 614static int 615compress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out) 616{ 617 u_char buf[4096]; 618 int r, status; 619 620 if (ssh->state->compression_out_started != 1) 621 return SSH_ERR_INTERNAL_ERROR; 622 623 /* This case is not handled below. */ 624 if (sshbuf_len(in) == 0) 625 return 0; 626 627 /* Input is the contents of the input buffer. */ 628 if ((ssh->state->compression_out_stream.next_in = 629 sshbuf_mutable_ptr(in)) == NULL) 630 return SSH_ERR_INTERNAL_ERROR; 631 ssh->state->compression_out_stream.avail_in = sshbuf_len(in); 632 633 /* Loop compressing until deflate() returns with avail_out != 0. */ 634 do { 635 /* Set up fixed-size output buffer. */ 636 ssh->state->compression_out_stream.next_out = buf; 637 ssh->state->compression_out_stream.avail_out = sizeof(buf); 638 639 /* Compress as much data into the buffer as possible. */ 640 status = deflate(&ssh->state->compression_out_stream, 641 Z_PARTIAL_FLUSH); 642 switch (status) { 643 case Z_MEM_ERROR: 644 return SSH_ERR_ALLOC_FAIL; 645 case Z_OK: 646 /* Append compressed data to output_buffer. */ 647 if ((r = sshbuf_put(out, buf, sizeof(buf) - 648 ssh->state->compression_out_stream.avail_out)) != 0) 649 return r; 650 break; 651 case Z_STREAM_ERROR: 652 default: 653 ssh->state->compression_out_failures++; 654 return SSH_ERR_INVALID_FORMAT; 655 } 656 } while (ssh->state->compression_out_stream.avail_out == 0); 657 return 0; 658} 659 660static int 661uncompress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out) 662{ 663 u_char buf[4096]; 664 int r, status; 665 666 if (ssh->state->compression_in_started != 1) 667 return SSH_ERR_INTERNAL_ERROR; 668 669 if ((ssh->state->compression_in_stream.next_in = 670 sshbuf_mutable_ptr(in)) == NULL) 671 return SSH_ERR_INTERNAL_ERROR; 672 ssh->state->compression_in_stream.avail_in = sshbuf_len(in); 673 674 for (;;) { 675 /* Set up fixed-size output buffer. */ 676 ssh->state->compression_in_stream.next_out = buf; 677 ssh->state->compression_in_stream.avail_out = sizeof(buf); 678 679 status = inflate(&ssh->state->compression_in_stream, 680 Z_PARTIAL_FLUSH); 681 switch (status) { 682 case Z_OK: 683 if ((r = sshbuf_put(out, buf, sizeof(buf) - 684 ssh->state->compression_in_stream.avail_out)) != 0) 685 return r; 686 break; 687 case Z_BUF_ERROR: 688 /* 689 * Comments in zlib.h say that we should keep calling 690 * inflate() until we get an error. This appears to 691 * be the error that we get. 692 */ 693 return 0; 694 case Z_DATA_ERROR: 695 return SSH_ERR_INVALID_FORMAT; 696 case Z_MEM_ERROR: 697 return SSH_ERR_ALLOC_FAIL; 698 case Z_STREAM_ERROR: 699 default: 700 ssh->state->compression_in_failures++; 701 return SSH_ERR_INTERNAL_ERROR; 702 } 703 } 704 /* NOTREACHED */ 705} 706 707/* Serialise compression state into a blob for privsep */ 708static int 709ssh_packet_get_compress_state(struct sshbuf *m, struct ssh *ssh) 710{ 711 struct session_state *state = ssh->state; 712 struct sshbuf *b; 713 int r; 714 715 if ((b = sshbuf_new()) == NULL) 716 return SSH_ERR_ALLOC_FAIL; 717 if (state->compression_in_started) { 718 if ((r = sshbuf_put_string(b, &state->compression_in_stream, 719 sizeof(state->compression_in_stream))) != 0) 720 goto out; 721 } else if ((r = sshbuf_put_string(b, NULL, 0)) != 0) 722 goto out; 723 if (state->compression_out_started) { 724 if ((r = sshbuf_put_string(b, &state->compression_out_stream, 725 sizeof(state->compression_out_stream))) != 0) 726 goto out; 727 } else if ((r = sshbuf_put_string(b, NULL, 0)) != 0) 728 goto out; 729 r = sshbuf_put_stringb(m, b); 730 out: 731 sshbuf_free(b); 732 return r; 733} 734 735/* Deserialise compression state from a blob for privsep */ 736static int 737ssh_packet_set_compress_state(struct ssh *ssh, struct sshbuf *m) 738{ 739 struct session_state *state = ssh->state; 740 struct sshbuf *b = NULL; 741 int r; 742 const u_char *inblob, *outblob; 743 size_t inl, outl; 744 745 if ((r = sshbuf_froms(m, &b)) != 0) 746 goto out; 747 if ((r = sshbuf_get_string_direct(b, &inblob, &inl)) != 0 || 748 (r = sshbuf_get_string_direct(b, &outblob, &outl)) != 0) 749 goto out; 750 if (inl == 0) 751 state->compression_in_started = 0; 752 else if (inl != sizeof(state->compression_in_stream)) { 753 r = SSH_ERR_INTERNAL_ERROR; 754 goto out; 755 } else { 756 state->compression_in_started = 1; 757 memcpy(&state->compression_in_stream, inblob, inl); 758 } 759 if (outl == 0) 760 state->compression_out_started = 0; 761 else if (outl != sizeof(state->compression_out_stream)) { 762 r = SSH_ERR_INTERNAL_ERROR; 763 goto out; 764 } else { 765 state->compression_out_started = 1; 766 memcpy(&state->compression_out_stream, outblob, outl); 767 } 768 r = 0; 769 out: 770 sshbuf_free(b); 771 return r; 772} 773 774void 775ssh_packet_set_compress_hooks(struct ssh *ssh, void *ctx, 776 void *(*allocfunc)(void *, u_int, u_int), 777 void (*freefunc)(void *, void *)) 778{ 779 ssh->state->compression_out_stream.zalloc = (alloc_func)allocfunc; 780 ssh->state->compression_out_stream.zfree = (free_func)freefunc; 781 ssh->state->compression_out_stream.opaque = ctx; 782 ssh->state->compression_in_stream.zalloc = (alloc_func)allocfunc; 783 ssh->state->compression_in_stream.zfree = (free_func)freefunc; 784 ssh->state->compression_in_stream.opaque = ctx; 785} 786 787/* 788 * Causes any further packets to be encrypted using the given key. The same 789 * key is used for both sending and reception. However, both directions are 790 * encrypted independently of each other. 791 */ 792 793void 794ssh_packet_set_encryption_key(struct ssh *ssh, const u_char *key, u_int keylen, int number) 795{ 796#ifndef WITH_SSH1 797 fatal("no SSH protocol 1 support"); 798#else /* WITH_SSH1 */ 799 struct session_state *state = ssh->state; 800 const struct sshcipher *cipher = cipher_by_number(number); 801 int r; 802 const char *wmsg; 803 804 if (cipher == NULL) 805 fatal("%s: unknown cipher number %d", __func__, number); 806 if (keylen < 20) 807 fatal("%s: keylen too small: %d", __func__, keylen); 808 if (keylen > SSH_SESSION_KEY_LENGTH) 809 fatal("%s: keylen too big: %d", __func__, keylen); 810 memcpy(state->ssh1_key, key, keylen); 811 state->ssh1_keylen = keylen; 812 if ((r = cipher_init(&state->send_context, cipher, key, keylen, 813 NULL, 0, CIPHER_ENCRYPT)) != 0 || 814 (r = cipher_init(&state->receive_context, cipher, key, keylen, 815 NULL, 0, CIPHER_DECRYPT) != 0)) 816 fatal("%s: cipher_init failed: %s", __func__, ssh_err(r)); 817 if (!state->cipher_warning_done && 818 ((wmsg = cipher_warning_message(&state->send_context)) != NULL || 819 (wmsg = cipher_warning_message(&state->send_context)) != NULL)) { 820 error("Warning: %s", wmsg); 821 state->cipher_warning_done = 1; 822 } 823#endif /* WITH_SSH1 */ 824} 825 826/* 827 * Finalizes and sends the packet. If the encryption key has been set, 828 * encrypts the packet before sending. 829 */ 830 831int 832ssh_packet_send1(struct ssh *ssh) 833{ 834 struct session_state *state = ssh->state; 835 u_char buf[8], *cp; 836 int r, padding, len; 837 u_int checksum; 838 839 /* 840 * If using packet compression, compress the payload of the outgoing 841 * packet. 842 */ 843 if (state->packet_compression) { 844 sshbuf_reset(state->compression_buffer); 845 /* Skip padding. */ 846 if ((r = sshbuf_consume(state->outgoing_packet, 8)) != 0) 847 goto out; 848 /* padding */ 849 if ((r = sshbuf_put(state->compression_buffer, 850 "\0\0\0\0\0\0\0\0", 8)) != 0) 851 goto out; 852 if ((r = compress_buffer(ssh, state->outgoing_packet, 853 state->compression_buffer)) != 0) 854 goto out; 855 sshbuf_reset(state->outgoing_packet); 856 if ((r = sshbuf_putb(state->outgoing_packet, 857 state->compression_buffer)) != 0) 858 goto out; 859 } 860 /* Compute packet length without padding (add checksum, remove padding). */ 861 len = sshbuf_len(state->outgoing_packet) + 4 - 8; 862 863 /* Insert padding. Initialized to zero in packet_start1() */ 864 padding = 8 - len % 8; 865 if (!state->send_context.plaintext) { 866 cp = sshbuf_mutable_ptr(state->outgoing_packet); 867 if (cp == NULL) { 868 r = SSH_ERR_INTERNAL_ERROR; 869 goto out; 870 } 871 arc4random_buf(cp + 8 - padding, padding); 872 } 873 if ((r = sshbuf_consume(state->outgoing_packet, 8 - padding)) != 0) 874 goto out; 875 876 /* Add check bytes. */ 877 checksum = ssh_crc32(sshbuf_ptr(state->outgoing_packet), 878 sshbuf_len(state->outgoing_packet)); 879 POKE_U32(buf, checksum); 880 if ((r = sshbuf_put(state->outgoing_packet, buf, 4)) != 0) 881 goto out; 882 883#ifdef PACKET_DEBUG 884 fprintf(stderr, "packet_send plain: "); 885 sshbuf_dump(state->outgoing_packet, stderr); 886#endif 887 888 /* Append to output. */ 889 POKE_U32(buf, len); 890 if ((r = sshbuf_put(state->output, buf, 4)) != 0) 891 goto out; 892 if ((r = sshbuf_reserve(state->output, 893 sshbuf_len(state->outgoing_packet), &cp)) != 0) 894 goto out; 895 if ((r = cipher_crypt(&state->send_context, 0, cp, 896 sshbuf_ptr(state->outgoing_packet), 897 sshbuf_len(state->outgoing_packet), 0, 0)) != 0) 898 goto out; 899 900#ifdef PACKET_DEBUG 901 fprintf(stderr, "encrypted: "); 902 sshbuf_dump(state->output, stderr); 903#endif 904 state->p_send.packets++; 905 state->p_send.bytes += len + 906 sshbuf_len(state->outgoing_packet); 907 sshbuf_reset(state->outgoing_packet); 908 909 /* 910 * Note that the packet is now only buffered in output. It won't be 911 * actually sent until ssh_packet_write_wait or ssh_packet_write_poll 912 * is called. 913 */ 914 r = 0; 915 out: 916 return r; 917} 918 919int 920ssh_set_newkeys(struct ssh *ssh, int mode) 921{ 922 struct session_state *state = ssh->state; 923 struct sshenc *enc; 924 struct sshmac *mac; 925 struct sshcomp *comp; 926 struct sshcipher_ctx *cc; 927 u_int64_t *max_blocks; 928 const char *wmsg; 929 int r, crypt_type; 930 931 debug2("set_newkeys: mode %d", mode); 932 933 if (mode == MODE_OUT) { 934 cc = &state->send_context; 935 crypt_type = CIPHER_ENCRYPT; 936 state->p_send.packets = state->p_send.blocks = 0; 937 max_blocks = &state->max_blocks_out; 938 } else { 939 cc = &state->receive_context; 940 crypt_type = CIPHER_DECRYPT; 941 state->p_read.packets = state->p_read.blocks = 0; 942 max_blocks = &state->max_blocks_in; 943 } 944 if (state->newkeys[mode] != NULL) { 945 debug("set_newkeys: rekeying"); 946 if ((r = cipher_cleanup(cc)) != 0) 947 return r; 948 enc = &state->newkeys[mode]->enc; 949 mac = &state->newkeys[mode]->mac; 950 comp = &state->newkeys[mode]->comp; 951 mac_clear(mac); 952 explicit_bzero(enc->iv, enc->iv_len); 953 explicit_bzero(enc->key, enc->key_len); 954 explicit_bzero(mac->key, mac->key_len); 955 free(enc->name); 956 free(enc->iv); 957 free(enc->key); 958 free(mac->name); 959 free(mac->key); 960 free(comp->name); 961 free(state->newkeys[mode]); 962 } 963 /* move newkeys from kex to state */ 964 if ((state->newkeys[mode] = ssh->kex->newkeys[mode]) == NULL) 965 return SSH_ERR_INTERNAL_ERROR; 966 ssh->kex->newkeys[mode] = NULL; 967 enc = &state->newkeys[mode]->enc; 968 mac = &state->newkeys[mode]->mac; 969 comp = &state->newkeys[mode]->comp; 970 if (cipher_authlen(enc->cipher) == 0) { 971 if ((r = mac_init(mac)) != 0) 972 return r; 973 } 974 mac->enabled = 1; 975 DBG(debug("cipher_init_context: %d", mode)); 976 if ((r = cipher_init(cc, enc->cipher, enc->key, enc->key_len, 977 enc->iv, enc->iv_len, crypt_type)) != 0) 978 return r; 979 if (!state->cipher_warning_done && 980 (wmsg = cipher_warning_message(cc)) != NULL) { 981 error("Warning: %s", wmsg); 982 state->cipher_warning_done = 1; 983 } 984 /* Deleting the keys does not gain extra security */ 985 /* explicit_bzero(enc->iv, enc->block_size); 986 explicit_bzero(enc->key, enc->key_len); 987 explicit_bzero(mac->key, mac->key_len); */ 988 if ((comp->type == COMP_ZLIB || 989 (comp->type == COMP_DELAYED && 990 state->after_authentication)) && comp->enabled == 0) { 991 if ((r = ssh_packet_init_compression(ssh)) < 0) 992 return r; 993 if (mode == MODE_OUT) { 994 if ((r = start_compression_out(ssh, 6)) != 0) 995 return r; 996 } else { 997 if ((r = start_compression_in(ssh)) != 0) 998 return r; 999 } 1000 comp->enabled = 1; 1001 } 1002 /* 1003 * The 2^(blocksize*2) limit is too expensive for 3DES, 1004 * blowfish, etc, so enforce a 1GB limit for small blocksizes. 1005 */ 1006 if (enc->block_size >= 16) 1007 *max_blocks = (u_int64_t)1 << (enc->block_size*2); 1008 else 1009 *max_blocks = ((u_int64_t)1 << 30) / enc->block_size; 1010 if (state->rekey_limit) 1011 *max_blocks = MIN(*max_blocks, 1012 state->rekey_limit / enc->block_size); 1013 return 0; 1014} 1015 1016/* 1017 * Delayed compression for SSH2 is enabled after authentication: 1018 * This happens on the server side after a SSH2_MSG_USERAUTH_SUCCESS is sent, 1019 * and on the client side after a SSH2_MSG_USERAUTH_SUCCESS is received. 1020 */ 1021static int 1022ssh_packet_enable_delayed_compress(struct ssh *ssh) 1023{ 1024 struct session_state *state = ssh->state; 1025 struct sshcomp *comp = NULL; 1026 int r, mode; 1027 1028 /* 1029 * Remember that we are past the authentication step, so rekeying 1030 * with COMP_DELAYED will turn on compression immediately. 1031 */ 1032 state->after_authentication = 1; 1033 for (mode = 0; mode < MODE_MAX; mode++) { 1034 /* protocol error: USERAUTH_SUCCESS received before NEWKEYS */ 1035 if (state->newkeys[mode] == NULL) 1036 continue; 1037 comp = &state->newkeys[mode]->comp; 1038 if (comp && !comp->enabled && comp->type == COMP_DELAYED) { 1039 if ((r = ssh_packet_init_compression(ssh)) != 0) 1040 return r; 1041 if (mode == MODE_OUT) { 1042 if ((r = start_compression_out(ssh, 6)) != 0) 1043 return r; 1044 } else { 1045 if ((r = start_compression_in(ssh)) != 0) 1046 return r; 1047 } 1048 comp->enabled = 1; 1049 } 1050 } 1051 return 0; 1052} 1053 1054/* 1055 * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue) 1056 */ 1057int 1058ssh_packet_send2_wrapped(struct ssh *ssh) 1059{ 1060 struct session_state *state = ssh->state; 1061 u_char type, *cp, macbuf[SSH_DIGEST_MAX_LENGTH]; 1062 u_char padlen, pad = 0; 1063 u_int authlen = 0, aadlen = 0; 1064 u_int len; 1065 struct sshenc *enc = NULL; 1066 struct sshmac *mac = NULL; 1067 struct sshcomp *comp = NULL; 1068 int r, block_size; 1069 1070 if (state->newkeys[MODE_OUT] != NULL) { 1071 enc = &state->newkeys[MODE_OUT]->enc; 1072 mac = &state->newkeys[MODE_OUT]->mac; 1073 comp = &state->newkeys[MODE_OUT]->comp; 1074 /* disable mac for authenticated encryption */ 1075 if ((authlen = cipher_authlen(enc->cipher)) != 0) 1076 mac = NULL; 1077 } 1078 block_size = enc ? enc->block_size : 8; 1079 aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0; 1080 1081 type = (sshbuf_ptr(state->outgoing_packet))[5]; 1082 1083#ifdef PACKET_DEBUG 1084 fprintf(stderr, "plain: "); 1085 sshbuf_dump(state->outgoing_packet, stderr); 1086#endif 1087 1088 if (comp && comp->enabled) { 1089 len = sshbuf_len(state->outgoing_packet); 1090 /* skip header, compress only payload */ 1091 if ((r = sshbuf_consume(state->outgoing_packet, 5)) != 0) 1092 goto out; 1093 sshbuf_reset(state->compression_buffer); 1094 if ((r = compress_buffer(ssh, state->outgoing_packet, 1095 state->compression_buffer)) != 0) 1096 goto out; 1097 sshbuf_reset(state->outgoing_packet); 1098 if ((r = sshbuf_put(state->outgoing_packet, 1099 "\0\0\0\0\0", 5)) != 0 || 1100 (r = sshbuf_putb(state->outgoing_packet, 1101 state->compression_buffer)) != 0) 1102 goto out; 1103 DBG(debug("compression: raw %d compressed %zd", len, 1104 sshbuf_len(state->outgoing_packet))); 1105 } 1106 1107 /* sizeof (packet_len + pad_len + payload) */ 1108 len = sshbuf_len(state->outgoing_packet); 1109 1110 /* 1111 * calc size of padding, alloc space, get random data, 1112 * minimum padding is 4 bytes 1113 */ 1114 len -= aadlen; /* packet length is not encrypted for EtM modes */ 1115 padlen = block_size - (len % block_size); 1116 if (padlen < 4) 1117 padlen += block_size; 1118 if (state->extra_pad) { 1119 /* will wrap if extra_pad+padlen > 255 */ 1120 state->extra_pad = 1121 roundup(state->extra_pad, block_size); 1122 pad = state->extra_pad - 1123 ((len + padlen) % state->extra_pad); 1124 DBG(debug3("%s: adding %d (len %d padlen %d extra_pad %d)", 1125 __func__, pad, len, padlen, state->extra_pad)); 1126 padlen += pad; 1127 state->extra_pad = 0; 1128 } 1129 if ((r = sshbuf_reserve(state->outgoing_packet, padlen, &cp)) != 0) 1130 goto out; 1131 if (enc && !state->send_context.plaintext) { 1132 /* random padding */ 1133 arc4random_buf(cp, padlen); 1134 } else { 1135 /* clear padding */ 1136 explicit_bzero(cp, padlen); 1137 } 1138 /* sizeof (packet_len + pad_len + payload + padding) */ 1139 len = sshbuf_len(state->outgoing_packet); 1140 cp = sshbuf_mutable_ptr(state->outgoing_packet); 1141 if (cp == NULL) { 1142 r = SSH_ERR_INTERNAL_ERROR; 1143 goto out; 1144 } 1145 /* packet_length includes payload, padding and padding length field */ 1146 POKE_U32(cp, len - 4); 1147 cp[4] = padlen; 1148 DBG(debug("send: len %d (includes padlen %d, aadlen %d)", 1149 len, padlen, aadlen)); 1150 1151 /* compute MAC over seqnr and packet(length fields, payload, padding) */ 1152 if (mac && mac->enabled && !mac->etm) { 1153 if ((r = mac_compute(mac, state->p_send.seqnr, 1154 sshbuf_ptr(state->outgoing_packet), len, 1155 macbuf, sizeof(macbuf))) != 0) 1156 goto out; 1157 DBG(debug("done calc MAC out #%d", state->p_send.seqnr)); 1158 } 1159 /* encrypt packet and append to output buffer. */ 1160 if ((r = sshbuf_reserve(state->output, 1161 sshbuf_len(state->outgoing_packet) + authlen, &cp)) != 0) 1162 goto out; 1163 if ((r = cipher_crypt(&state->send_context, state->p_send.seqnr, cp, 1164 sshbuf_ptr(state->outgoing_packet), 1165 len - aadlen, aadlen, authlen)) != 0) 1166 goto out; 1167 /* append unencrypted MAC */ 1168 if (mac && mac->enabled) { 1169 if (mac->etm) { 1170 /* EtM: compute mac over aadlen + cipher text */ 1171 if ((r = mac_compute(mac, state->p_send.seqnr, 1172 cp, len, macbuf, sizeof(macbuf))) != 0) 1173 goto out; 1174 DBG(debug("done calc MAC(EtM) out #%d", 1175 state->p_send.seqnr)); 1176 } 1177 if ((r = sshbuf_put(state->output, macbuf, mac->mac_len)) != 0) 1178 goto out; 1179 } 1180#ifdef PACKET_DEBUG 1181 fprintf(stderr, "encrypted: "); 1182 sshbuf_dump(state->output, stderr); 1183#endif 1184 /* increment sequence number for outgoing packets */ 1185 if (++state->p_send.seqnr == 0) 1186 logit("outgoing seqnr wraps around"); 1187 if (++state->p_send.packets == 0) 1188 if (!(ssh->compat & SSH_BUG_NOREKEY)) 1189 return SSH_ERR_NEED_REKEY; 1190 state->p_send.blocks += len / block_size; 1191 state->p_send.bytes += len; 1192 sshbuf_reset(state->outgoing_packet); 1193 1194 if (type == SSH2_MSG_NEWKEYS) 1195 r = ssh_set_newkeys(ssh, MODE_OUT); 1196 else if (type == SSH2_MSG_USERAUTH_SUCCESS && state->server_side) 1197 r = ssh_packet_enable_delayed_compress(ssh); 1198 else 1199 r = 0; 1200 out: 1201 return r; 1202} 1203 1204int 1205ssh_packet_send2(struct ssh *ssh) 1206{ 1207 struct session_state *state = ssh->state; 1208 struct packet *p; 1209 u_char type; 1210 int r; 1211 1212 type = sshbuf_ptr(state->outgoing_packet)[5]; 1213 1214 /* during rekeying we can only send key exchange messages */ 1215 if (state->rekeying) { 1216 if ((type < SSH2_MSG_TRANSPORT_MIN) || 1217 (type > SSH2_MSG_TRANSPORT_MAX) || 1218 (type == SSH2_MSG_SERVICE_REQUEST) || 1219 (type == SSH2_MSG_SERVICE_ACCEPT)) { 1220 debug("enqueue packet: %u", type); 1221 p = calloc(1, sizeof(*p)); 1222 if (p == NULL) 1223 return SSH_ERR_ALLOC_FAIL; 1224 p->type = type; 1225 p->payload = state->outgoing_packet; 1226 TAILQ_INSERT_TAIL(&state->outgoing, p, next); 1227 state->outgoing_packet = sshbuf_new(); 1228 if (state->outgoing_packet == NULL) 1229 return SSH_ERR_ALLOC_FAIL; 1230 return 0; 1231 } 1232 } 1233 1234 /* rekeying starts with sending KEXINIT */ 1235 if (type == SSH2_MSG_KEXINIT) 1236 state->rekeying = 1; 1237 1238 if ((r = ssh_packet_send2_wrapped(ssh)) != 0) 1239 return r; 1240 1241 /* after a NEWKEYS message we can send the complete queue */ 1242 if (type == SSH2_MSG_NEWKEYS) { 1243 state->rekeying = 0; 1244 state->rekey_time = monotime(); 1245 while ((p = TAILQ_FIRST(&state->outgoing))) { 1246 type = p->type; 1247 debug("dequeue packet: %u", type); 1248 sshbuf_free(state->outgoing_packet); 1249 state->outgoing_packet = p->payload; 1250 TAILQ_REMOVE(&state->outgoing, p, next); 1251 free(p); 1252 if ((r = ssh_packet_send2_wrapped(ssh)) != 0) 1253 return r; 1254 } 1255 } 1256 return 0; 1257} 1258 1259/* 1260 * Waits until a packet has been received, and returns its type. Note that 1261 * no other data is processed until this returns, so this function should not 1262 * be used during the interactive session. 1263 */ 1264 1265int 1266ssh_packet_read_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1267{ 1268 struct session_state *state = ssh->state; 1269 int len, r, ms_remain, cont; 1270 fd_set *setp; 1271 char buf[8192]; 1272 struct timeval timeout, start, *timeoutp = NULL; 1273 1274 DBG(debug("packet_read()")); 1275 1276 setp = calloc(howmany(state->connection_in + 1, 1277 NFDBITS), sizeof(fd_mask)); 1278 if (setp == NULL) 1279 return SSH_ERR_ALLOC_FAIL; 1280 1281 /* 1282 * Since we are blocking, ensure that all written packets have 1283 * been sent. 1284 */ 1285 if ((r = ssh_packet_write_wait(ssh)) != 0) 1286 goto out; 1287 1288 /* Stay in the loop until we have received a complete packet. */ 1289 for (;;) { 1290 /* Try to read a packet from the buffer. */ 1291 r = ssh_packet_read_poll_seqnr(ssh, typep, seqnr_p); 1292 if (r != 0) 1293 break; 1294 if (!compat20 && ( 1295 *typep == SSH_SMSG_SUCCESS 1296 || *typep == SSH_SMSG_FAILURE 1297 || *typep == SSH_CMSG_EOF 1298 || *typep == SSH_CMSG_EXIT_CONFIRMATION)) 1299 if ((r = sshpkt_get_end(ssh)) != 0) 1300 break; 1301 /* If we got a packet, return it. */ 1302 if (*typep != SSH_MSG_NONE) 1303 break; 1304 /* 1305 * Otherwise, wait for some data to arrive, add it to the 1306 * buffer, and try again. 1307 */ 1308 memset(setp, 0, howmany(state->connection_in + 1, 1309 NFDBITS) * sizeof(fd_mask)); 1310 FD_SET(state->connection_in, setp); 1311 1312 if (state->packet_timeout_ms > 0) { 1313 ms_remain = state->packet_timeout_ms; 1314 timeoutp = &timeout; 1315 } 1316 /* Wait for some data to arrive. */ 1317 for (;;) { 1318 if (state->packet_timeout_ms != -1) { 1319 ms_to_timeval(&timeout, ms_remain); 1320 gettimeofday(&start, NULL); 1321 } 1322 if ((r = select(state->connection_in + 1, setp, 1323 NULL, NULL, timeoutp)) >= 0) 1324 break; 1325 if (errno != EAGAIN && errno != EINTR && 1326 errno != EWOULDBLOCK) 1327 break; 1328 if (state->packet_timeout_ms == -1) 1329 continue; 1330 ms_subtract_diff(&start, &ms_remain); 1331 if (ms_remain <= 0) { 1332 r = 0; 1333 break; 1334 } 1335 } 1336 if (r == 0) 1337 return SSH_ERR_CONN_TIMEOUT; 1338 /* Read data from the socket. */ 1339 do { 1340 cont = 0; 1341 len = roaming_read(state->connection_in, buf, 1342 sizeof(buf), &cont); 1343 } while (len == 0 && cont); 1344 if (len == 0) { 1345 r = SSH_ERR_CONN_CLOSED; 1346 goto out; 1347 } 1348 if (len < 0) { 1349 r = SSH_ERR_SYSTEM_ERROR; 1350 goto out; 1351 } 1352 1353 /* Append it to the buffer. */ 1354 if ((r = ssh_packet_process_incoming(ssh, buf, len)) != 0) 1355 goto out; 1356 } 1357 out: 1358 free(setp); 1359 return r; 1360} 1361 1362int 1363ssh_packet_read(struct ssh *ssh) 1364{ 1365 u_char type; 1366 int r; 1367 1368 if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0) 1369 fatal("%s: %s", __func__, ssh_err(r)); 1370 return type; 1371} 1372 1373/* 1374 * Waits until a packet has been received, verifies that its type matches 1375 * that given, and gives a fatal error and exits if there is a mismatch. 1376 */ 1377 1378int 1379ssh_packet_read_expect(struct ssh *ssh, u_int expected_type) 1380{ 1381 int r; 1382 u_char type; 1383 1384 if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0) 1385 return r; 1386 if (type != expected_type) { 1387 if ((r = sshpkt_disconnect(ssh, 1388 "Protocol error: expected packet type %d, got %d", 1389 expected_type, type)) != 0) 1390 return r; 1391 return SSH_ERR_PROTOCOL_ERROR; 1392 } 1393 return 0; 1394} 1395 1396/* Checks if a full packet is available in the data received so far via 1397 * packet_process_incoming. If so, reads the packet; otherwise returns 1398 * SSH_MSG_NONE. This does not wait for data from the connection. 1399 * 1400 * SSH_MSG_DISCONNECT is handled specially here. Also, 1401 * SSH_MSG_IGNORE messages are skipped by this function and are never returned 1402 * to higher levels. 1403 */ 1404 1405int 1406ssh_packet_read_poll1(struct ssh *ssh, u_char *typep) 1407{ 1408 struct session_state *state = ssh->state; 1409 u_int len, padded_len; 1410 const char *emsg; 1411 const u_char *cp; 1412 u_char *p; 1413 u_int checksum, stored_checksum; 1414 int r; 1415 1416 *typep = SSH_MSG_NONE; 1417 1418 /* Check if input size is less than minimum packet size. */ 1419 if (sshbuf_len(state->input) < 4 + 8) 1420 return 0; 1421 /* Get length of incoming packet. */ 1422 len = PEEK_U32(sshbuf_ptr(state->input)); 1423 if (len < 1 + 2 + 2 || len > 256 * 1024) { 1424 if ((r = sshpkt_disconnect(ssh, "Bad packet length %u", 1425 len)) != 0) 1426 return r; 1427 return SSH_ERR_CONN_CORRUPT; 1428 } 1429 padded_len = (len + 8) & ~7; 1430 1431 /* Check if the packet has been entirely received. */ 1432 if (sshbuf_len(state->input) < 4 + padded_len) 1433 return 0; 1434 1435 /* The entire packet is in buffer. */ 1436 1437 /* Consume packet length. */ 1438 if ((r = sshbuf_consume(state->input, 4)) != 0) 1439 goto out; 1440 1441 /* 1442 * Cryptographic attack detector for ssh 1443 * (C)1998 CORE-SDI, Buenos Aires Argentina 1444 * Ariel Futoransky(futo@core-sdi.com) 1445 */ 1446 if (!state->receive_context.plaintext) { 1447 emsg = NULL; 1448 switch (detect_attack(&state->deattack, 1449 sshbuf_ptr(state->input), padded_len)) { 1450 case DEATTACK_OK: 1451 break; 1452 case DEATTACK_DETECTED: 1453 emsg = "crc32 compensation attack detected"; 1454 break; 1455 case DEATTACK_DOS_DETECTED: 1456 emsg = "deattack denial of service detected"; 1457 break; 1458 default: 1459 emsg = "deattack error"; 1460 break; 1461 } 1462 if (emsg != NULL) { 1463 error("%s", emsg); 1464 if ((r = sshpkt_disconnect(ssh, "%s", emsg)) != 0 || 1465 (r = ssh_packet_write_wait(ssh)) != 0) 1466 return r; 1467 return SSH_ERR_CONN_CORRUPT; 1468 } 1469 } 1470 1471 /* Decrypt data to incoming_packet. */ 1472 sshbuf_reset(state->incoming_packet); 1473 if ((r = sshbuf_reserve(state->incoming_packet, padded_len, &p)) != 0) 1474 goto out; 1475 if ((r = cipher_crypt(&state->receive_context, 0, p, 1476 sshbuf_ptr(state->input), padded_len, 0, 0)) != 0) 1477 goto out; 1478 1479 if ((r = sshbuf_consume(state->input, padded_len)) != 0) 1480 goto out; 1481 1482#ifdef PACKET_DEBUG 1483 fprintf(stderr, "read_poll plain: "); 1484 sshbuf_dump(state->incoming_packet, stderr); 1485#endif 1486 1487 /* Compute packet checksum. */ 1488 checksum = ssh_crc32(sshbuf_ptr(state->incoming_packet), 1489 sshbuf_len(state->incoming_packet) - 4); 1490 1491 /* Skip padding. */ 1492 if ((r = sshbuf_consume(state->incoming_packet, 8 - len % 8)) != 0) 1493 goto out; 1494 1495 /* Test check bytes. */ 1496 if (len != sshbuf_len(state->incoming_packet)) { 1497 error("%s: len %d != sshbuf_len %zd", __func__, 1498 len, sshbuf_len(state->incoming_packet)); 1499 if ((r = sshpkt_disconnect(ssh, "invalid packet length")) != 0 || 1500 (r = ssh_packet_write_wait(ssh)) != 0) 1501 return r; 1502 return SSH_ERR_CONN_CORRUPT; 1503 } 1504 1505 cp = sshbuf_ptr(state->incoming_packet) + len - 4; 1506 stored_checksum = PEEK_U32(cp); 1507 if (checksum != stored_checksum) { 1508 error("Corrupted check bytes on input"); 1509 if ((r = sshpkt_disconnect(ssh, "connection corrupted")) != 0 || 1510 (r = ssh_packet_write_wait(ssh)) != 0) 1511 return r; 1512 return SSH_ERR_CONN_CORRUPT; 1513 } 1514 if ((r = sshbuf_consume_end(state->incoming_packet, 4)) < 0) 1515 goto out; 1516 1517 if (state->packet_compression) { 1518 sshbuf_reset(state->compression_buffer); 1519 if ((r = uncompress_buffer(ssh, state->incoming_packet, 1520 state->compression_buffer)) != 0) 1521 goto out; 1522 sshbuf_reset(state->incoming_packet); 1523 if ((r = sshbuf_putb(state->incoming_packet, 1524 state->compression_buffer)) != 0) 1525 goto out; 1526 } 1527 state->p_read.packets++; 1528 state->p_read.bytes += padded_len + 4; 1529 if ((r = sshbuf_get_u8(state->incoming_packet, typep)) != 0) 1530 goto out; 1531 if (*typep < SSH_MSG_MIN || *typep > SSH_MSG_MAX) { 1532 error("Invalid ssh1 packet type: %d", *typep); 1533 if ((r = sshpkt_disconnect(ssh, "invalid packet type")) != 0 || 1534 (r = ssh_packet_write_wait(ssh)) != 0) 1535 return r; 1536 return SSH_ERR_PROTOCOL_ERROR; 1537 } 1538 r = 0; 1539 out: 1540 return r; 1541} 1542 1543int 1544ssh_packet_read_poll2(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1545{ 1546 struct session_state *state = ssh->state; 1547 u_int padlen, need; 1548 u_char *cp, macbuf[SSH_DIGEST_MAX_LENGTH]; 1549 u_int maclen, aadlen = 0, authlen = 0, block_size; 1550 struct sshenc *enc = NULL; 1551 struct sshmac *mac = NULL; 1552 struct sshcomp *comp = NULL; 1553 int r; 1554 1555 *typep = SSH_MSG_NONE; 1556 1557 if (state->packet_discard) 1558 return 0; 1559 1560 if (state->newkeys[MODE_IN] != NULL) { 1561 enc = &state->newkeys[MODE_IN]->enc; 1562 mac = &state->newkeys[MODE_IN]->mac; 1563 comp = &state->newkeys[MODE_IN]->comp; 1564 /* disable mac for authenticated encryption */ 1565 if ((authlen = cipher_authlen(enc->cipher)) != 0) 1566 mac = NULL; 1567 } 1568 maclen = mac && mac->enabled ? mac->mac_len : 0; 1569 block_size = enc ? enc->block_size : 8; 1570 aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0; 1571 1572 if (aadlen && state->packlen == 0) { 1573 if (cipher_get_length(&state->receive_context, 1574 &state->packlen, state->p_read.seqnr, 1575 sshbuf_ptr(state->input), sshbuf_len(state->input)) != 0) 1576 return 0; 1577 if (state->packlen < 1 + 4 || 1578 state->packlen > PACKET_MAX_SIZE) { 1579#ifdef PACKET_DEBUG 1580 sshbuf_dump(state->input, stderr); 1581#endif 1582 logit("Bad packet length %u.", state->packlen); 1583 if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0) 1584 return r; 1585 return SSH_ERR_CONN_CORRUPT; 1586 } 1587 sshbuf_reset(state->incoming_packet); 1588 } else if (state->packlen == 0) { 1589 /* 1590 * check if input size is less than the cipher block size, 1591 * decrypt first block and extract length of incoming packet 1592 */ 1593 if (sshbuf_len(state->input) < block_size) 1594 return 0; 1595 sshbuf_reset(state->incoming_packet); 1596 if ((r = sshbuf_reserve(state->incoming_packet, block_size, 1597 &cp)) != 0) 1598 goto out; 1599 if ((r = cipher_crypt(&state->receive_context, 1600 state->p_send.seqnr, cp, sshbuf_ptr(state->input), 1601 block_size, 0, 0)) != 0) 1602 goto out; 1603 state->packlen = PEEK_U32(sshbuf_ptr(state->incoming_packet)); 1604 if (state->packlen < 1 + 4 || 1605 state->packlen > PACKET_MAX_SIZE) { 1606#ifdef PACKET_DEBUG 1607 fprintf(stderr, "input: \n"); 1608 sshbuf_dump(state->input, stderr); 1609 fprintf(stderr, "incoming_packet: \n"); 1610 sshbuf_dump(state->incoming_packet, stderr); 1611#endif 1612 logit("Bad packet length %u.", state->packlen); 1613 return ssh_packet_start_discard(ssh, enc, mac, 1614 state->packlen, PACKET_MAX_SIZE); 1615 } 1616 if ((r = sshbuf_consume(state->input, block_size)) != 0) 1617 goto out; 1618 } 1619 DBG(debug("input: packet len %u", state->packlen+4)); 1620 1621 if (aadlen) { 1622 /* only the payload is encrypted */ 1623 need = state->packlen; 1624 } else { 1625 /* 1626 * the payload size and the payload are encrypted, but we 1627 * have a partial packet of block_size bytes 1628 */ 1629 need = 4 + state->packlen - block_size; 1630 } 1631 DBG(debug("partial packet: block %d, need %d, maclen %d, authlen %d," 1632 " aadlen %d", block_size, need, maclen, authlen, aadlen)); 1633 if (need % block_size != 0) { 1634 logit("padding error: need %d block %d mod %d", 1635 need, block_size, need % block_size); 1636 return ssh_packet_start_discard(ssh, enc, mac, 1637 state->packlen, PACKET_MAX_SIZE - block_size); 1638 } 1639 /* 1640 * check if the entire packet has been received and 1641 * decrypt into incoming_packet: 1642 * 'aadlen' bytes are unencrypted, but authenticated. 1643 * 'need' bytes are encrypted, followed by either 1644 * 'authlen' bytes of authentication tag or 1645 * 'maclen' bytes of message authentication code. 1646 */ 1647 if (sshbuf_len(state->input) < aadlen + need + authlen + maclen) 1648 return 0; 1649#ifdef PACKET_DEBUG 1650 fprintf(stderr, "read_poll enc/full: "); 1651 sshbuf_dump(state->input, stderr); 1652#endif 1653 /* EtM: compute mac over encrypted input */ 1654 if (mac && mac->enabled && mac->etm) { 1655 if ((r = mac_compute(mac, state->p_read.seqnr, 1656 sshbuf_ptr(state->input), aadlen + need, 1657 macbuf, sizeof(macbuf))) != 0) 1658 goto out; 1659 } 1660 if ((r = sshbuf_reserve(state->incoming_packet, aadlen + need, 1661 &cp)) != 0) 1662 goto out; 1663 if ((r = cipher_crypt(&state->receive_context, state->p_read.seqnr, cp, 1664 sshbuf_ptr(state->input), need, aadlen, authlen)) != 0) 1665 goto out; 1666 if ((r = sshbuf_consume(state->input, aadlen + need + authlen)) != 0) 1667 goto out; 1668 /* 1669 * compute MAC over seqnr and packet, 1670 * increment sequence number for incoming packet 1671 */ 1672 if (mac && mac->enabled) { 1673 if (!mac->etm) 1674 if ((r = mac_compute(mac, state->p_read.seqnr, 1675 sshbuf_ptr(state->incoming_packet), 1676 sshbuf_len(state->incoming_packet), 1677 macbuf, sizeof(macbuf))) != 0) 1678 goto out; 1679 if (timingsafe_bcmp(macbuf, sshbuf_ptr(state->input), 1680 mac->mac_len) != 0) { 1681 logit("Corrupted MAC on input."); 1682 if (need > PACKET_MAX_SIZE) 1683 return SSH_ERR_INTERNAL_ERROR; 1684 return ssh_packet_start_discard(ssh, enc, mac, 1685 state->packlen, PACKET_MAX_SIZE - need); 1686 } 1687 1688 DBG(debug("MAC #%d ok", state->p_read.seqnr)); 1689 if ((r = sshbuf_consume(state->input, mac->mac_len)) != 0) 1690 goto out; 1691 } 1692 if (seqnr_p != NULL) 1693 *seqnr_p = state->p_read.seqnr; 1694 if (++state->p_read.seqnr == 0) 1695 logit("incoming seqnr wraps around"); 1696 if (++state->p_read.packets == 0) 1697 if (!(ssh->compat & SSH_BUG_NOREKEY)) 1698 return SSH_ERR_NEED_REKEY; 1699 state->p_read.blocks += (state->packlen + 4) / block_size; 1700 state->p_read.bytes += state->packlen + 4; 1701 1702 /* get padlen */ 1703 padlen = sshbuf_ptr(state->incoming_packet)[4]; 1704 DBG(debug("input: padlen %d", padlen)); 1705 if (padlen < 4) { 1706 if ((r = sshpkt_disconnect(ssh, 1707 "Corrupted padlen %d on input.", padlen)) != 0 || 1708 (r = ssh_packet_write_wait(ssh)) != 0) 1709 return r; 1710 return SSH_ERR_CONN_CORRUPT; 1711 } 1712 1713 /* skip packet size + padlen, discard padding */ 1714 if ((r = sshbuf_consume(state->incoming_packet, 4 + 1)) != 0 || 1715 ((r = sshbuf_consume_end(state->incoming_packet, padlen)) != 0)) 1716 goto out; 1717 1718 DBG(debug("input: len before de-compress %zd", 1719 sshbuf_len(state->incoming_packet))); 1720 if (comp && comp->enabled) { 1721 sshbuf_reset(state->compression_buffer); 1722 if ((r = uncompress_buffer(ssh, state->incoming_packet, 1723 state->compression_buffer)) != 0) 1724 goto out; 1725 sshbuf_reset(state->incoming_packet); 1726 if ((r = sshbuf_putb(state->incoming_packet, 1727 state->compression_buffer)) != 0) 1728 goto out; 1729 DBG(debug("input: len after de-compress %zd", 1730 sshbuf_len(state->incoming_packet))); 1731 } 1732 /* 1733 * get packet type, implies consume. 1734 * return length of payload (without type field) 1735 */ 1736 if ((r = sshbuf_get_u8(state->incoming_packet, typep)) != 0) 1737 goto out; 1738 if (*typep < SSH2_MSG_MIN || *typep >= SSH2_MSG_LOCAL_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 (*typep == SSH2_MSG_NEWKEYS) 1746 r = ssh_set_newkeys(ssh, MODE_IN); 1747 else if (*typep == SSH2_MSG_USERAUTH_SUCCESS && !state->server_side) 1748 r = ssh_packet_enable_delayed_compress(ssh); 1749 else 1750 r = 0; 1751#ifdef PACKET_DEBUG 1752 fprintf(stderr, "read/plain[%d]:\r\n", *typep); 1753 sshbuf_dump(state->incoming_packet, stderr); 1754#endif 1755 /* reset for next packet */ 1756 state->packlen = 0; 1757 out: 1758 return r; 1759} 1760 1761int 1762ssh_packet_read_poll_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1763{ 1764 struct session_state *state = ssh->state; 1765 u_int reason, seqnr; 1766 int r; 1767 u_char *msg; 1768 1769 for (;;) { 1770 msg = NULL; 1771 if (compat20) { 1772 r = ssh_packet_read_poll2(ssh, typep, seqnr_p); 1773 if (r != 0) 1774 return r; 1775 if (*typep) { 1776 state->keep_alive_timeouts = 0; 1777 DBG(debug("received packet type %d", *typep)); 1778 } 1779 switch (*typep) { 1780 case SSH2_MSG_IGNORE: 1781 debug3("Received SSH2_MSG_IGNORE"); 1782 break; 1783 case SSH2_MSG_DEBUG: 1784 if ((r = sshpkt_get_u8(ssh, NULL)) != 0 || 1785 (r = sshpkt_get_string(ssh, &msg, NULL)) != 0 || 1786 (r = sshpkt_get_string(ssh, NULL, NULL)) != 0) { 1787 if (msg) 1788 free(msg); 1789 return r; 1790 } 1791 debug("Remote: %.900s", msg); 1792 free(msg); 1793 break; 1794 case SSH2_MSG_DISCONNECT: 1795 if ((r = sshpkt_get_u32(ssh, &reason)) != 0 || 1796 (r = sshpkt_get_string(ssh, &msg, NULL)) != 0) 1797 return r; 1798 /* Ignore normal client exit notifications */ 1799 do_log2(ssh->state->server_side && 1800 reason == SSH2_DISCONNECT_BY_APPLICATION ? 1801 SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_ERROR, 1802 "Received disconnect from %s: %u: %.400s", 1803 ssh_remote_ipaddr(ssh), reason, msg); 1804 free(msg); 1805 return SSH_ERR_DISCONNECTED; 1806 case SSH2_MSG_UNIMPLEMENTED: 1807 if ((r = sshpkt_get_u32(ssh, &seqnr)) != 0) 1808 return r; 1809 debug("Received SSH2_MSG_UNIMPLEMENTED for %u", 1810 seqnr); 1811 break; 1812 default: 1813 return 0; 1814 } 1815 } else { 1816 r = ssh_packet_read_poll1(ssh, typep); 1817 switch (*typep) { 1818 case SSH_MSG_NONE: 1819 return SSH_MSG_NONE; 1820 case SSH_MSG_IGNORE: 1821 break; 1822 case SSH_MSG_DEBUG: 1823 if ((r = sshpkt_get_string(ssh, &msg, NULL)) != 0) 1824 return r; 1825 debug("Remote: %.900s", msg); 1826 free(msg); 1827 break; 1828 case SSH_MSG_DISCONNECT: 1829 if ((r = sshpkt_get_string(ssh, &msg, NULL)) != 0) 1830 return r; 1831 logit("Received disconnect from %s: %.400s", 1832 ssh_remote_ipaddr(ssh), msg); 1833 free(msg); 1834 return SSH_ERR_DISCONNECTED; 1835 default: 1836 DBG(debug("received packet type %d", *typep)); 1837 return 0; 1838 } 1839 } 1840 } 1841} 1842 1843/* 1844 * Buffers the given amount of input characters. This is intended to be used 1845 * together with packet_read_poll. 1846 */ 1847 1848int 1849ssh_packet_process_incoming(struct ssh *ssh, const char *buf, u_int len) 1850{ 1851 struct session_state *state = ssh->state; 1852 int r; 1853 1854 if (state->packet_discard) { 1855 state->keep_alive_timeouts = 0; /* ?? */ 1856 if (len >= state->packet_discard) { 1857 if ((r = ssh_packet_stop_discard(ssh)) != 0) 1858 return r; 1859 } 1860 state->packet_discard -= len; 1861 return 0; 1862 } 1863 if ((r = sshbuf_put(ssh->state->input, buf, len)) != 0) 1864 return r; 1865 1866 return 0; 1867} 1868 1869int 1870ssh_packet_remaining(struct ssh *ssh) 1871{ 1872 return sshbuf_len(ssh->state->incoming_packet); 1873} 1874 1875/* 1876 * Sends a diagnostic message from the server to the client. This message 1877 * can be sent at any time (but not while constructing another message). The 1878 * message is printed immediately, but only if the client is being executed 1879 * in verbose mode. These messages are primarily intended to ease debugging 1880 * authentication problems. The length of the formatted message must not 1881 * exceed 1024 bytes. This will automatically call ssh_packet_write_wait. 1882 */ 1883void 1884ssh_packet_send_debug(struct ssh *ssh, const char *fmt,...) 1885{ 1886 char buf[1024]; 1887 va_list args; 1888 int r; 1889 1890 if (compat20 && (ssh->compat & SSH_BUG_DEBUG)) 1891 return; 1892 1893 va_start(args, fmt); 1894 vsnprintf(buf, sizeof(buf), fmt, args); 1895 va_end(args); 1896 1897 if (compat20) { 1898 if ((r = sshpkt_start(ssh, SSH2_MSG_DEBUG)) != 0 || 1899 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* always display */ 1900 (r = sshpkt_put_cstring(ssh, buf)) != 0 || 1901 (r = sshpkt_put_cstring(ssh, "")) != 0 || 1902 (r = sshpkt_send(ssh)) != 0) 1903 fatal("%s: %s", __func__, ssh_err(r)); 1904 } else { 1905 if ((r = sshpkt_start(ssh, SSH_MSG_DEBUG)) != 0 || 1906 (r = sshpkt_put_cstring(ssh, buf)) != 0 || 1907 (r = sshpkt_send(ssh)) != 0) 1908 fatal("%s: %s", __func__, ssh_err(r)); 1909 } 1910 if ((r = ssh_packet_write_wait(ssh)) != 0) 1911 fatal("%s: %s", __func__, ssh_err(r)); 1912} 1913 1914/* 1915 * Pretty-print connection-terminating errors and exit. 1916 */ 1917void 1918sshpkt_fatal(struct ssh *ssh, const char *tag, int r) 1919{ 1920 switch (r) { 1921 case SSH_ERR_CONN_CLOSED: 1922 logit("Connection closed by %.200s", ssh_remote_ipaddr(ssh)); 1923 cleanup_exit(255); 1924 case SSH_ERR_CONN_TIMEOUT: 1925 logit("Connection to %.200s timed out", ssh_remote_ipaddr(ssh)); 1926 cleanup_exit(255); 1927 case SSH_ERR_DISCONNECTED: 1928 logit("Disconnected from %.200s", 1929 ssh_remote_ipaddr(ssh)); 1930 cleanup_exit(255); 1931 case SSH_ERR_SYSTEM_ERROR: 1932 if (errno == ECONNRESET) { 1933 logit("Connection reset by %.200s", 1934 ssh_remote_ipaddr(ssh)); 1935 cleanup_exit(255); 1936 } 1937 /* FALLTHROUGH */ 1938 case SSH_ERR_NO_CIPHER_ALG_MATCH: 1939 case SSH_ERR_NO_MAC_ALG_MATCH: 1940 case SSH_ERR_NO_COMPRESS_ALG_MATCH: 1941 case SSH_ERR_NO_KEX_ALG_MATCH: 1942 case SSH_ERR_NO_HOSTKEY_ALG_MATCH: 1943 if (ssh && ssh->kex && ssh->kex->failed_choice) { 1944 fatal("Unable to negotiate with %.200s: %s. " 1945 "Their offer: %s", ssh_remote_ipaddr(ssh), 1946 ssh_err(r), ssh->kex->failed_choice); 1947 } 1948 /* FALLTHROUGH */ 1949 default: 1950 fatal("%s%sConnection to %.200s: %s", 1951 tag != NULL ? tag : "", tag != NULL ? ": " : "", 1952 ssh_remote_ipaddr(ssh), ssh_err(r)); 1953 } 1954} 1955 1956/* 1957 * Logs the error plus constructs and sends a disconnect packet, closes the 1958 * connection, and exits. This function never returns. The error message 1959 * should not contain a newline. The length of the formatted message must 1960 * not exceed 1024 bytes. 1961 */ 1962void 1963ssh_packet_disconnect(struct ssh *ssh, const char *fmt,...) 1964{ 1965 char buf[1024]; 1966 va_list args; 1967 static int disconnecting = 0; 1968 int r; 1969 1970 if (disconnecting) /* Guard against recursive invocations. */ 1971 fatal("packet_disconnect called recursively."); 1972 disconnecting = 1; 1973 1974 /* 1975 * Format the message. Note that the caller must make sure the 1976 * message is of limited size. 1977 */ 1978 va_start(args, fmt); 1979 vsnprintf(buf, sizeof(buf), fmt, args); 1980 va_end(args); 1981 1982 /* Display the error locally */ 1983 logit("Disconnecting: %.100s", buf); 1984 1985 /* 1986 * Send the disconnect message to the other side, and wait 1987 * for it to get sent. 1988 */ 1989 if ((r = sshpkt_disconnect(ssh, "%s", buf)) != 0) 1990 sshpkt_fatal(ssh, __func__, r); 1991 1992 if ((r = ssh_packet_write_wait(ssh)) != 0) 1993 sshpkt_fatal(ssh, __func__, r); 1994 1995 /* Close the connection. */ 1996 ssh_packet_close(ssh); 1997 cleanup_exit(255); 1998} 1999 2000/* 2001 * Checks if there is any buffered output, and tries to write some of 2002 * the output. 2003 */ 2004int 2005ssh_packet_write_poll(struct ssh *ssh) 2006{ 2007 struct session_state *state = ssh->state; 2008 int len = sshbuf_len(state->output); 2009 int cont, r; 2010 2011 if (len > 0) { 2012 cont = 0; 2013 len = roaming_write(state->connection_out, 2014 sshbuf_ptr(state->output), len, &cont); 2015 if (len == -1) { 2016 if (errno == EINTR || errno == EAGAIN || 2017 errno == EWOULDBLOCK) 2018 return 0; 2019 return SSH_ERR_SYSTEM_ERROR; 2020 } 2021 if (len == 0 && !cont) 2022 return SSH_ERR_CONN_CLOSED; 2023 if ((r = sshbuf_consume(state->output, len)) != 0) 2024 return r; 2025 } 2026 return 0; 2027} 2028 2029/* 2030 * Calls packet_write_poll repeatedly until all pending output data has been 2031 * written. 2032 */ 2033int 2034ssh_packet_write_wait(struct ssh *ssh) 2035{ 2036 fd_set *setp; 2037 int ret, r, ms_remain = 0; 2038 struct timeval start, timeout, *timeoutp = NULL; 2039 struct session_state *state = ssh->state; 2040 2041 setp = calloc(howmany(state->connection_out + 1, 2042 NFDBITS), sizeof(fd_mask)); 2043 if (setp == NULL) 2044 return SSH_ERR_ALLOC_FAIL; 2045 ssh_packet_write_poll(ssh); 2046 while (ssh_packet_have_data_to_write(ssh)) { 2047 memset(setp, 0, howmany(state->connection_out + 1, 2048 NFDBITS) * sizeof(fd_mask)); 2049 FD_SET(state->connection_out, setp); 2050 2051 if (state->packet_timeout_ms > 0) { 2052 ms_remain = state->packet_timeout_ms; 2053 timeoutp = &timeout; 2054 } 2055 for (;;) { 2056 if (state->packet_timeout_ms != -1) { 2057 ms_to_timeval(&timeout, ms_remain); 2058 gettimeofday(&start, NULL); 2059 } 2060 if ((ret = select(state->connection_out + 1, 2061 NULL, setp, NULL, timeoutp)) >= 0) 2062 break; 2063 if (errno != EAGAIN && errno != EINTR && 2064 errno != EWOULDBLOCK) 2065 break; 2066 if (state->packet_timeout_ms == -1) 2067 continue; 2068 ms_subtract_diff(&start, &ms_remain); 2069 if (ms_remain <= 0) { 2070 ret = 0; 2071 break; 2072 } 2073 } 2074 if (ret == 0) { 2075 free(setp); 2076 return SSH_ERR_CONN_TIMEOUT; 2077 } 2078 if ((r = ssh_packet_write_poll(ssh)) != 0) { 2079 free(setp); 2080 return r; 2081 } 2082 } 2083 free(setp); 2084 return 0; 2085} 2086 2087/* Returns true if there is buffered data to write to the connection. */ 2088 2089int 2090ssh_packet_have_data_to_write(struct ssh *ssh) 2091{ 2092 return sshbuf_len(ssh->state->output) != 0; 2093} 2094 2095/* Returns true if there is not too much data to write to the connection. */ 2096 2097int 2098ssh_packet_not_very_much_data_to_write(struct ssh *ssh) 2099{ 2100 if (ssh->state->interactive_mode) 2101 return sshbuf_len(ssh->state->output) < 16384; 2102 else 2103 return sshbuf_len(ssh->state->output) < 128 * 1024; 2104} 2105 2106void 2107ssh_packet_set_tos(struct ssh *ssh, int tos) 2108{ 2109#ifndef IP_TOS_IS_BROKEN 2110 if (!ssh_packet_connection_is_on_socket(ssh)) 2111 return; 2112 switch (ssh_packet_connection_af(ssh)) { 2113# ifdef IP_TOS 2114 case AF_INET: 2115 debug3("%s: set IP_TOS 0x%02x", __func__, tos); 2116 if (setsockopt(ssh->state->connection_in, 2117 IPPROTO_IP, IP_TOS, &tos, sizeof(tos)) < 0) 2118 error("setsockopt IP_TOS %d: %.100s:", 2119 tos, strerror(errno)); 2120 break; 2121# endif /* IP_TOS */ 2122# ifdef IPV6_TCLASS 2123 case AF_INET6: 2124 debug3("%s: set IPV6_TCLASS 0x%02x", __func__, tos); 2125 if (setsockopt(ssh->state->connection_in, 2126 IPPROTO_IPV6, IPV6_TCLASS, &tos, sizeof(tos)) < 0) 2127 error("setsockopt IPV6_TCLASS %d: %.100s:", 2128 tos, strerror(errno)); 2129 break; 2130# endif /* IPV6_TCLASS */ 2131 } 2132#endif /* IP_TOS_IS_BROKEN */ 2133} 2134 2135/* Informs that the current session is interactive. Sets IP flags for that. */ 2136 2137void 2138ssh_packet_set_interactive(struct ssh *ssh, int interactive, int qos_interactive, int qos_bulk) 2139{ 2140 struct session_state *state = ssh->state; 2141 2142 if (state->set_interactive_called) 2143 return; 2144 state->set_interactive_called = 1; 2145 2146 /* Record that we are in interactive mode. */ 2147 state->interactive_mode = interactive; 2148 2149 /* Only set socket options if using a socket. */ 2150 if (!ssh_packet_connection_is_on_socket(ssh)) 2151 return; 2152 set_nodelay(state->connection_in); 2153 ssh_packet_set_tos(ssh, interactive ? qos_interactive : 2154 qos_bulk); 2155} 2156 2157/* Returns true if the current connection is interactive. */ 2158 2159int 2160ssh_packet_is_interactive(struct ssh *ssh) 2161{ 2162 return ssh->state->interactive_mode; 2163} 2164 2165int 2166ssh_packet_set_maxsize(struct ssh *ssh, u_int s) 2167{ 2168 struct session_state *state = ssh->state; 2169 2170 if (state->set_maxsize_called) { 2171 logit("packet_set_maxsize: called twice: old %d new %d", 2172 state->max_packet_size, s); 2173 return -1; 2174 } 2175 if (s < 4 * 1024 || s > 1024 * 1024) { 2176 logit("packet_set_maxsize: bad size %d", s); 2177 return -1; 2178 } 2179 state->set_maxsize_called = 1; 2180 debug("packet_set_maxsize: setting to %d", s); 2181 state->max_packet_size = s; 2182 return s; 2183} 2184 2185int 2186ssh_packet_inc_alive_timeouts(struct ssh *ssh) 2187{ 2188 return ++ssh->state->keep_alive_timeouts; 2189} 2190 2191void 2192ssh_packet_set_alive_timeouts(struct ssh *ssh, int ka) 2193{ 2194 ssh->state->keep_alive_timeouts = ka; 2195} 2196 2197u_int 2198ssh_packet_get_maxsize(struct ssh *ssh) 2199{ 2200 return ssh->state->max_packet_size; 2201} 2202 2203/* 2204 * 9.2. Ignored Data Message 2205 * 2206 * byte SSH_MSG_IGNORE 2207 * string data 2208 * 2209 * All implementations MUST understand (and ignore) this message at any 2210 * time (after receiving the protocol version). No implementation is 2211 * required to send them. This message can be used as an additional 2212 * protection measure against advanced traffic analysis techniques. 2213 */ 2214void 2215ssh_packet_send_ignore(struct ssh *ssh, int nbytes) 2216{ 2217 u_int32_t rnd = 0; 2218 int r, i; 2219 2220 if ((r = sshpkt_start(ssh, compat20 ? 2221 SSH2_MSG_IGNORE : SSH_MSG_IGNORE)) != 0 || 2222 (r = sshpkt_put_u32(ssh, nbytes)) != 0) 2223 fatal("%s: %s", __func__, ssh_err(r)); 2224 for (i = 0; i < nbytes; i++) { 2225 if (i % 4 == 0) 2226 rnd = arc4random(); 2227 if ((r = sshpkt_put_u8(ssh, (u_char)rnd & 0xff)) != 0) 2228 fatal("%s: %s", __func__, ssh_err(r)); 2229 rnd >>= 8; 2230 } 2231} 2232 2233#define MAX_PACKETS (1U<<31) 2234int 2235ssh_packet_need_rekeying(struct ssh *ssh) 2236{ 2237 struct session_state *state = ssh->state; 2238 2239 if (ssh->compat & SSH_BUG_NOREKEY) 2240 return 0; 2241 return 2242 (state->p_send.packets > MAX_PACKETS) || 2243 (state->p_read.packets > MAX_PACKETS) || 2244 (state->max_blocks_out && 2245 (state->p_send.blocks > state->max_blocks_out)) || 2246 (state->max_blocks_in && 2247 (state->p_read.blocks > state->max_blocks_in)) || 2248 (state->rekey_interval != 0 && state->rekey_time + 2249 state->rekey_interval <= monotime()); 2250} 2251 2252void 2253ssh_packet_set_rekey_limits(struct ssh *ssh, u_int32_t bytes, time_t seconds) 2254{ 2255 debug3("rekey after %lld bytes, %d seconds", (long long)bytes, 2256 (int)seconds); 2257 ssh->state->rekey_limit = bytes; 2258 ssh->state->rekey_interval = seconds; 2259} 2260 2261time_t 2262ssh_packet_get_rekey_timeout(struct ssh *ssh) 2263{ 2264 time_t seconds; 2265 2266 seconds = ssh->state->rekey_time + ssh->state->rekey_interval - 2267 monotime(); 2268 return (seconds <= 0 ? 1 : seconds); 2269} 2270 2271void 2272ssh_packet_set_server(struct ssh *ssh) 2273{ 2274 ssh->state->server_side = 1; 2275} 2276 2277void 2278ssh_packet_set_authenticated(struct ssh *ssh) 2279{ 2280 ssh->state->after_authentication = 1; 2281} 2282 2283void * 2284ssh_packet_get_input(struct ssh *ssh) 2285{ 2286 return (void *)ssh->state->input; 2287} 2288 2289void * 2290ssh_packet_get_output(struct ssh *ssh) 2291{ 2292 return (void *)ssh->state->output; 2293} 2294 2295/* XXX TODO update roaming to new API (does not work anyway) */ 2296/* 2297 * Save the state for the real connection, and use a separate state when 2298 * resuming a suspended connection. 2299 */ 2300void 2301ssh_packet_backup_state(struct ssh *ssh, 2302 struct ssh *backup_state) 2303{ 2304 struct ssh *tmp; 2305 2306 close(ssh->state->connection_in); 2307 ssh->state->connection_in = -1; 2308 close(ssh->state->connection_out); 2309 ssh->state->connection_out = -1; 2310 if (backup_state) 2311 tmp = backup_state; 2312 else 2313 tmp = ssh_alloc_session_state(); 2314 backup_state = ssh; 2315 ssh = tmp; 2316} 2317 2318/* XXX FIXME FIXME FIXME */ 2319/* 2320 * Swap in the old state when resuming a connecion. 2321 */ 2322void 2323ssh_packet_restore_state(struct ssh *ssh, 2324 struct ssh *backup_state) 2325{ 2326 struct ssh *tmp; 2327 u_int len; 2328 int r; 2329 2330 tmp = backup_state; 2331 backup_state = ssh; 2332 ssh = tmp; 2333 ssh->state->connection_in = backup_state->state->connection_in; 2334 backup_state->state->connection_in = -1; 2335 ssh->state->connection_out = backup_state->state->connection_out; 2336 backup_state->state->connection_out = -1; 2337 len = sshbuf_len(backup_state->state->input); 2338 if (len > 0) { 2339 if ((r = sshbuf_putb(ssh->state->input, 2340 backup_state->state->input)) != 0) 2341 fatal("%s: %s", __func__, ssh_err(r)); 2342 sshbuf_reset(backup_state->state->input); 2343 add_recv_bytes(len); 2344 } 2345} 2346 2347/* Reset after_authentication and reset compression in post-auth privsep */ 2348static int 2349ssh_packet_set_postauth(struct ssh *ssh) 2350{ 2351 struct sshcomp *comp; 2352 int r, mode; 2353 2354 debug("%s: called", __func__); 2355 /* This was set in net child, but is not visible in user child */ 2356 ssh->state->after_authentication = 1; 2357 ssh->state->rekeying = 0; 2358 for (mode = 0; mode < MODE_MAX; mode++) { 2359 if (ssh->state->newkeys[mode] == NULL) 2360 continue; 2361 comp = &ssh->state->newkeys[mode]->comp; 2362 if (comp && comp->enabled && 2363 (r = ssh_packet_init_compression(ssh)) != 0) 2364 return r; 2365 } 2366 return 0; 2367} 2368 2369/* Packet state (de-)serialization for privsep */ 2370 2371/* turn kex into a blob for packet state serialization */ 2372static int 2373kex_to_blob(struct sshbuf *m, struct kex *kex) 2374{ 2375 int r; 2376 2377 if ((r = sshbuf_put_string(m, kex->session_id, 2378 kex->session_id_len)) != 0 || 2379 (r = sshbuf_put_u32(m, kex->we_need)) != 0 || 2380 (r = sshbuf_put_u32(m, kex->hostkey_type)) != 0 || 2381 (r = sshbuf_put_u32(m, kex->kex_type)) != 0 || 2382 (r = sshbuf_put_stringb(m, kex->my)) != 0 || 2383 (r = sshbuf_put_stringb(m, kex->peer)) != 0 || 2384 (r = sshbuf_put_u32(m, kex->flags)) != 0 || 2385 (r = sshbuf_put_cstring(m, kex->client_version_string)) != 0 || 2386 (r = sshbuf_put_cstring(m, kex->server_version_string)) != 0) 2387 return r; 2388 return 0; 2389} 2390 2391/* turn key exchange results into a blob for packet state serialization */ 2392static int 2393newkeys_to_blob(struct sshbuf *m, struct ssh *ssh, int mode) 2394{ 2395 struct sshbuf *b; 2396 struct sshcipher_ctx *cc; 2397 struct sshcomp *comp; 2398 struct sshenc *enc; 2399 struct sshmac *mac; 2400 struct newkeys *newkey; 2401 int r; 2402 2403 if ((newkey = ssh->state->newkeys[mode]) == NULL) 2404 return SSH_ERR_INTERNAL_ERROR; 2405 enc = &newkey->enc; 2406 mac = &newkey->mac; 2407 comp = &newkey->comp; 2408 cc = (mode == MODE_OUT) ? &ssh->state->send_context : 2409 &ssh->state->receive_context; 2410 if ((r = cipher_get_keyiv(cc, enc->iv, enc->iv_len)) != 0) 2411 return r; 2412 if ((b = sshbuf_new()) == NULL) 2413 return SSH_ERR_ALLOC_FAIL; 2414 /* The cipher struct is constant and shared, you export pointer */ 2415 if ((r = sshbuf_put_cstring(b, enc->name)) != 0 || 2416 (r = sshbuf_put(b, &enc->cipher, sizeof(enc->cipher))) != 0 || 2417 (r = sshbuf_put_u32(b, enc->enabled)) != 0 || 2418 (r = sshbuf_put_u32(b, enc->block_size)) != 0 || 2419 (r = sshbuf_put_string(b, enc->key, enc->key_len)) != 0 || 2420 (r = sshbuf_put_string(b, enc->iv, enc->iv_len)) != 0) 2421 goto out; 2422 if (cipher_authlen(enc->cipher) == 0) { 2423 if ((r = sshbuf_put_cstring(b, mac->name)) != 0 || 2424 (r = sshbuf_put_u32(b, mac->enabled)) != 0 || 2425 (r = sshbuf_put_string(b, mac->key, mac->key_len)) != 0) 2426 goto out; 2427 } 2428 if ((r = sshbuf_put_u32(b, comp->type)) != 0 || 2429 (r = sshbuf_put_u32(b, comp->enabled)) != 0 || 2430 (r = sshbuf_put_cstring(b, comp->name)) != 0) 2431 goto out; 2432 r = sshbuf_put_stringb(m, b); 2433 out: 2434 if (b != NULL) 2435 sshbuf_free(b); 2436 return r; 2437} 2438 2439/* serialize packet state into a blob */ 2440int 2441ssh_packet_get_state(struct ssh *ssh, struct sshbuf *m) 2442{ 2443 struct session_state *state = ssh->state; 2444 u_char *p; 2445 size_t slen, rlen; 2446 int r, ssh1cipher; 2447 2448 if (!compat20) { 2449 ssh1cipher = cipher_get_number(state->receive_context.cipher); 2450 slen = cipher_get_keyiv_len(&state->send_context); 2451 rlen = cipher_get_keyiv_len(&state->receive_context); 2452 if ((r = sshbuf_put_u32(m, state->remote_protocol_flags)) != 0 || 2453 (r = sshbuf_put_u32(m, ssh1cipher)) != 0 || 2454 (r = sshbuf_put_string(m, state->ssh1_key, state->ssh1_keylen)) != 0 || 2455 (r = sshbuf_put_u32(m, slen)) != 0 || 2456 (r = sshbuf_reserve(m, slen, &p)) != 0 || 2457 (r = cipher_get_keyiv(&state->send_context, p, slen)) != 0 || 2458 (r = sshbuf_put_u32(m, rlen)) != 0 || 2459 (r = sshbuf_reserve(m, rlen, &p)) != 0 || 2460 (r = cipher_get_keyiv(&state->receive_context, p, rlen)) != 0) 2461 return r; 2462 } else { 2463 if ((r = kex_to_blob(m, ssh->kex)) != 0 || 2464 (r = newkeys_to_blob(m, ssh, MODE_OUT)) != 0 || 2465 (r = newkeys_to_blob(m, ssh, MODE_IN)) != 0 || 2466 (r = sshbuf_put_u32(m, state->rekey_limit)) != 0 || 2467 (r = sshbuf_put_u32(m, state->rekey_interval)) != 0 || 2468 (r = sshbuf_put_u32(m, state->p_send.seqnr)) != 0 || 2469 (r = sshbuf_put_u64(m, state->p_send.blocks)) != 0 || 2470 (r = sshbuf_put_u32(m, state->p_send.packets)) != 0 || 2471 (r = sshbuf_put_u64(m, state->p_send.bytes)) != 0 || 2472 (r = sshbuf_put_u32(m, state->p_read.seqnr)) != 0 || 2473 (r = sshbuf_put_u64(m, state->p_read.blocks)) != 0 || 2474 (r = sshbuf_put_u32(m, state->p_read.packets)) != 0 || 2475 (r = sshbuf_put_u64(m, state->p_read.bytes)) != 0) 2476 return r; 2477 } 2478 2479 slen = cipher_get_keycontext(&state->send_context, NULL); 2480 rlen = cipher_get_keycontext(&state->receive_context, NULL); 2481 if ((r = sshbuf_put_u32(m, slen)) != 0 || 2482 (r = sshbuf_reserve(m, slen, &p)) != 0) 2483 return r; 2484 if (cipher_get_keycontext(&state->send_context, p) != (int)slen) 2485 return SSH_ERR_INTERNAL_ERROR; 2486 if ((r = sshbuf_put_u32(m, rlen)) != 0 || 2487 (r = sshbuf_reserve(m, rlen, &p)) != 0) 2488 return r; 2489 if (cipher_get_keycontext(&state->receive_context, p) != (int)rlen) 2490 return SSH_ERR_INTERNAL_ERROR; 2491 2492 if ((r = ssh_packet_get_compress_state(m, ssh)) != 0 || 2493 (r = sshbuf_put_stringb(m, state->input)) != 0 || 2494 (r = sshbuf_put_stringb(m, state->output)) != 0) 2495 return r; 2496 2497 if (compat20) { 2498 if ((r = sshbuf_put_u64(m, get_sent_bytes())) != 0 || 2499 (r = sshbuf_put_u64(m, get_recv_bytes())) != 0) 2500 return r; 2501 } 2502 return 0; 2503} 2504 2505/* restore key exchange results from blob for packet state de-serialization */ 2506static int 2507newkeys_from_blob(struct sshbuf *m, struct ssh *ssh, int mode) 2508{ 2509 struct sshbuf *b = NULL; 2510 struct sshcomp *comp; 2511 struct sshenc *enc; 2512 struct sshmac *mac; 2513 struct newkeys *newkey = NULL; 2514 size_t keylen, ivlen, maclen; 2515 int r; 2516 2517 if ((newkey = calloc(1, sizeof(*newkey))) == NULL) { 2518 r = SSH_ERR_ALLOC_FAIL; 2519 goto out; 2520 } 2521 if ((r = sshbuf_froms(m, &b)) != 0) 2522 goto out; 2523#ifdef DEBUG_PK 2524 sshbuf_dump(b, stderr); 2525#endif 2526 enc = &newkey->enc; 2527 mac = &newkey->mac; 2528 comp = &newkey->comp; 2529 2530 if ((r = sshbuf_get_cstring(b, &enc->name, NULL)) != 0 || 2531 (r = sshbuf_get(b, &enc->cipher, sizeof(enc->cipher))) != 0 || 2532 (r = sshbuf_get_u32(b, (u_int *)&enc->enabled)) != 0 || 2533 (r = sshbuf_get_u32(b, &enc->block_size)) != 0 || 2534 (r = sshbuf_get_string(b, &enc->key, &keylen)) != 0 || 2535 (r = sshbuf_get_string(b, &enc->iv, &ivlen)) != 0) 2536 goto out; 2537 if (cipher_authlen(enc->cipher) == 0) { 2538 if ((r = sshbuf_get_cstring(b, &mac->name, NULL)) != 0) 2539 goto out; 2540 if ((r = mac_setup(mac, mac->name)) != 0) 2541 goto out; 2542 if ((r = sshbuf_get_u32(b, (u_int *)&mac->enabled)) != 0 || 2543 (r = sshbuf_get_string(b, &mac->key, &maclen)) != 0) 2544 goto out; 2545 if (maclen > mac->key_len) { 2546 r = SSH_ERR_INVALID_FORMAT; 2547 goto out; 2548 } 2549 mac->key_len = maclen; 2550 } 2551 if ((r = sshbuf_get_u32(b, &comp->type)) != 0 || 2552 (r = sshbuf_get_u32(b, (u_int *)&comp->enabled)) != 0 || 2553 (r = sshbuf_get_cstring(b, &comp->name, NULL)) != 0) 2554 goto out; 2555 if (enc->name == NULL || 2556 cipher_by_name(enc->name) != enc->cipher) { 2557 r = SSH_ERR_INVALID_FORMAT; 2558 goto out; 2559 } 2560 if (sshbuf_len(b) != 0) { 2561 r = SSH_ERR_INVALID_FORMAT; 2562 goto out; 2563 } 2564 enc->key_len = keylen; 2565 enc->iv_len = ivlen; 2566 ssh->kex->newkeys[mode] = newkey; 2567 newkey = NULL; 2568 r = 0; 2569 out: 2570 if (newkey != NULL) 2571 free(newkey); 2572 if (b != NULL) 2573 sshbuf_free(b); 2574 return r; 2575} 2576 2577/* restore kex from blob for packet state de-serialization */ 2578static int 2579kex_from_blob(struct sshbuf *m, struct kex **kexp) 2580{ 2581 struct kex *kex; 2582 int r; 2583 2584 if ((kex = calloc(1, sizeof(struct kex))) == NULL || 2585 (kex->my = sshbuf_new()) == NULL || 2586 (kex->peer = sshbuf_new()) == NULL) { 2587 r = SSH_ERR_ALLOC_FAIL; 2588 goto out; 2589 } 2590 if ((r = sshbuf_get_string(m, &kex->session_id, &kex->session_id_len)) != 0 || 2591 (r = sshbuf_get_u32(m, &kex->we_need)) != 0 || 2592 (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_type)) != 0 || 2593 (r = sshbuf_get_u32(m, &kex->kex_type)) != 0 || 2594 (r = sshbuf_get_stringb(m, kex->my)) != 0 || 2595 (r = sshbuf_get_stringb(m, kex->peer)) != 0 || 2596 (r = sshbuf_get_u32(m, &kex->flags)) != 0 || 2597 (r = sshbuf_get_cstring(m, &kex->client_version_string, NULL)) != 0 || 2598 (r = sshbuf_get_cstring(m, &kex->server_version_string, NULL)) != 0) 2599 goto out; 2600 kex->server = 1; 2601 kex->done = 1; 2602 r = 0; 2603 out: 2604 if (r != 0 || kexp == NULL) { 2605 if (kex != NULL) { 2606 if (kex->my != NULL) 2607 sshbuf_free(kex->my); 2608 if (kex->peer != NULL) 2609 sshbuf_free(kex->peer); 2610 free(kex); 2611 } 2612 if (kexp != NULL) 2613 *kexp = NULL; 2614 } else { 2615 *kexp = kex; 2616 } 2617 return r; 2618} 2619 2620/* 2621 * Restore packet state from content of blob 'm' (de-serialization). 2622 * Note that 'm' will be partially consumed on parsing or any other errors. 2623 */ 2624int 2625ssh_packet_set_state(struct ssh *ssh, struct sshbuf *m) 2626{ 2627 struct session_state *state = ssh->state; 2628 const u_char *ssh1key, *ivin, *ivout, *keyin, *keyout, *input, *output; 2629 size_t ssh1keylen, rlen, slen, ilen, olen; 2630 int r; 2631 u_int ssh1cipher = 0; 2632 u_int64_t sent_bytes = 0, recv_bytes = 0; 2633 2634 if (!compat20) { 2635 if ((r = sshbuf_get_u32(m, &state->remote_protocol_flags)) != 0 || 2636 (r = sshbuf_get_u32(m, &ssh1cipher)) != 0 || 2637 (r = sshbuf_get_string_direct(m, &ssh1key, &ssh1keylen)) != 0 || 2638 (r = sshbuf_get_string_direct(m, &ivout, &slen)) != 0 || 2639 (r = sshbuf_get_string_direct(m, &ivin, &rlen)) != 0) 2640 return r; 2641 if (ssh1cipher > INT_MAX) 2642 return SSH_ERR_KEY_UNKNOWN_CIPHER; 2643 ssh_packet_set_encryption_key(ssh, ssh1key, ssh1keylen, 2644 (int)ssh1cipher); 2645 if (cipher_get_keyiv_len(&state->send_context) != (int)slen || 2646 cipher_get_keyiv_len(&state->receive_context) != (int)rlen) 2647 return SSH_ERR_INVALID_FORMAT; 2648 if ((r = cipher_set_keyiv(&state->send_context, ivout)) != 0 || 2649 (r = cipher_set_keyiv(&state->receive_context, ivin)) != 0) 2650 return r; 2651 } else { 2652 if ((r = kex_from_blob(m, &ssh->kex)) != 0 || 2653 (r = newkeys_from_blob(m, ssh, MODE_OUT)) != 0 || 2654 (r = newkeys_from_blob(m, ssh, MODE_IN)) != 0 || 2655 (r = sshbuf_get_u32(m, &state->rekey_limit)) != 0 || 2656 (r = sshbuf_get_u32(m, &state->rekey_interval)) != 0 || 2657 (r = sshbuf_get_u32(m, &state->p_send.seqnr)) != 0 || 2658 (r = sshbuf_get_u64(m, &state->p_send.blocks)) != 0 || 2659 (r = sshbuf_get_u32(m, &state->p_send.packets)) != 0 || 2660 (r = sshbuf_get_u64(m, &state->p_send.bytes)) != 0 || 2661 (r = sshbuf_get_u32(m, &state->p_read.seqnr)) != 0 || 2662 (r = sshbuf_get_u64(m, &state->p_read.blocks)) != 0 || 2663 (r = sshbuf_get_u32(m, &state->p_read.packets)) != 0 || 2664 (r = sshbuf_get_u64(m, &state->p_read.bytes)) != 0) 2665 return r; 2666 /* 2667 * We set the time here so that in post-auth privsep slave we 2668 * count from the completion of the authentication. 2669 */ 2670 state->rekey_time = monotime(); 2671 /* XXX ssh_set_newkeys overrides p_read.packets? XXX */ 2672 if ((r = ssh_set_newkeys(ssh, MODE_IN)) != 0 || 2673 (r = ssh_set_newkeys(ssh, MODE_OUT)) != 0) 2674 return r; 2675 } 2676 if ((r = sshbuf_get_string_direct(m, &keyout, &slen)) != 0 || 2677 (r = sshbuf_get_string_direct(m, &keyin, &rlen)) != 0) 2678 return r; 2679 if (cipher_get_keycontext(&state->send_context, NULL) != (int)slen || 2680 cipher_get_keycontext(&state->receive_context, NULL) != (int)rlen) 2681 return SSH_ERR_INVALID_FORMAT; 2682 cipher_set_keycontext(&state->send_context, keyout); 2683 cipher_set_keycontext(&state->receive_context, keyin); 2684 2685 if ((r = ssh_packet_set_compress_state(ssh, m)) != 0 || 2686 (r = ssh_packet_set_postauth(ssh)) != 0) 2687 return r; 2688 2689 sshbuf_reset(state->input); 2690 sshbuf_reset(state->output); 2691 if ((r = sshbuf_get_string_direct(m, &input, &ilen)) != 0 || 2692 (r = sshbuf_get_string_direct(m, &output, &olen)) != 0 || 2693 (r = sshbuf_put(state->input, input, ilen)) != 0 || 2694 (r = sshbuf_put(state->output, output, olen)) != 0) 2695 return r; 2696 2697 if (compat20) { 2698 if ((r = sshbuf_get_u64(m, &sent_bytes)) != 0 || 2699 (r = sshbuf_get_u64(m, &recv_bytes)) != 0) 2700 return r; 2701 roam_set_bytes(sent_bytes, recv_bytes); 2702 } 2703 if (sshbuf_len(m)) 2704 return SSH_ERR_INVALID_FORMAT; 2705 debug3("%s: done", __func__); 2706 return 0; 2707} 2708 2709/* NEW API */ 2710 2711/* put data to the outgoing packet */ 2712 2713int 2714sshpkt_put(struct ssh *ssh, const void *v, size_t len) 2715{ 2716 return sshbuf_put(ssh->state->outgoing_packet, v, len); 2717} 2718 2719int 2720sshpkt_putb(struct ssh *ssh, const struct sshbuf *b) 2721{ 2722 return sshbuf_putb(ssh->state->outgoing_packet, b); 2723} 2724 2725int 2726sshpkt_put_u8(struct ssh *ssh, u_char val) 2727{ 2728 return sshbuf_put_u8(ssh->state->outgoing_packet, val); 2729} 2730 2731int 2732sshpkt_put_u32(struct ssh *ssh, u_int32_t val) 2733{ 2734 return sshbuf_put_u32(ssh->state->outgoing_packet, val); 2735} 2736 2737int 2738sshpkt_put_u64(struct ssh *ssh, u_int64_t val) 2739{ 2740 return sshbuf_put_u64(ssh->state->outgoing_packet, val); 2741} 2742 2743int 2744sshpkt_put_string(struct ssh *ssh, const void *v, size_t len) 2745{ 2746 return sshbuf_put_string(ssh->state->outgoing_packet, v, len); 2747} 2748 2749int 2750sshpkt_put_cstring(struct ssh *ssh, const void *v) 2751{ 2752 return sshbuf_put_cstring(ssh->state->outgoing_packet, v); 2753} 2754 2755int 2756sshpkt_put_stringb(struct ssh *ssh, const struct sshbuf *v) 2757{ 2758 return sshbuf_put_stringb(ssh->state->outgoing_packet, v); 2759} 2760 2761#ifdef WITH_OPENSSL 2762#ifdef OPENSSL_HAS_ECC 2763int 2764sshpkt_put_ec(struct ssh *ssh, const EC_POINT *v, const EC_GROUP *g) 2765{ 2766 return sshbuf_put_ec(ssh->state->outgoing_packet, v, g); 2767} 2768#endif /* OPENSSL_HAS_ECC */ 2769 2770#ifdef WITH_SSH1 2771int 2772sshpkt_put_bignum1(struct ssh *ssh, const BIGNUM *v) 2773{ 2774 return sshbuf_put_bignum1(ssh->state->outgoing_packet, v); 2775} 2776#endif /* WITH_SSH1 */ 2777 2778int 2779sshpkt_put_bignum2(struct ssh *ssh, const BIGNUM *v) 2780{ 2781 return sshbuf_put_bignum2(ssh->state->outgoing_packet, v); 2782} 2783#endif /* WITH_OPENSSL */ 2784 2785/* fetch data from the incoming packet */ 2786 2787int 2788sshpkt_get(struct ssh *ssh, void *valp, size_t len) 2789{ 2790 return sshbuf_get(ssh->state->incoming_packet, valp, len); 2791} 2792 2793int 2794sshpkt_get_u8(struct ssh *ssh, u_char *valp) 2795{ 2796 return sshbuf_get_u8(ssh->state->incoming_packet, valp); 2797} 2798 2799int 2800sshpkt_get_u32(struct ssh *ssh, u_int32_t *valp) 2801{ 2802 return sshbuf_get_u32(ssh->state->incoming_packet, valp); 2803} 2804 2805int 2806sshpkt_get_u64(struct ssh *ssh, u_int64_t *valp) 2807{ 2808 return sshbuf_get_u64(ssh->state->incoming_packet, valp); 2809} 2810 2811int 2812sshpkt_get_string(struct ssh *ssh, u_char **valp, size_t *lenp) 2813{ 2814 return sshbuf_get_string(ssh->state->incoming_packet, valp, lenp); 2815} 2816 2817int 2818sshpkt_get_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp) 2819{ 2820 return sshbuf_get_string_direct(ssh->state->incoming_packet, valp, lenp); 2821} 2822 2823int 2824sshpkt_get_cstring(struct ssh *ssh, char **valp, size_t *lenp) 2825{ 2826 return sshbuf_get_cstring(ssh->state->incoming_packet, valp, lenp); 2827} 2828 2829#ifdef WITH_OPENSSL 2830#ifdef OPENSSL_HAS_ECC 2831int 2832sshpkt_get_ec(struct ssh *ssh, EC_POINT *v, const EC_GROUP *g) 2833{ 2834 return sshbuf_get_ec(ssh->state->incoming_packet, v, g); 2835} 2836#endif /* OPENSSL_HAS_ECC */ 2837 2838#ifdef WITH_SSH1 2839int 2840sshpkt_get_bignum1(struct ssh *ssh, BIGNUM *v) 2841{ 2842 return sshbuf_get_bignum1(ssh->state->incoming_packet, v); 2843} 2844#endif /* WITH_SSH1 */ 2845 2846int 2847sshpkt_get_bignum2(struct ssh *ssh, BIGNUM *v) 2848{ 2849 return sshbuf_get_bignum2(ssh->state->incoming_packet, v); 2850} 2851#endif /* WITH_OPENSSL */ 2852 2853int 2854sshpkt_get_end(struct ssh *ssh) 2855{ 2856 if (sshbuf_len(ssh->state->incoming_packet) > 0) 2857 return SSH_ERR_UNEXPECTED_TRAILING_DATA; 2858 return 0; 2859} 2860 2861const u_char * 2862sshpkt_ptr(struct ssh *ssh, size_t *lenp) 2863{ 2864 if (lenp != NULL) 2865 *lenp = sshbuf_len(ssh->state->incoming_packet); 2866 return sshbuf_ptr(ssh->state->incoming_packet); 2867} 2868 2869/* start a new packet */ 2870 2871int 2872sshpkt_start(struct ssh *ssh, u_char type) 2873{ 2874 u_char buf[9]; 2875 int len; 2876 2877 DBG(debug("packet_start[%d]", type)); 2878 len = compat20 ? 6 : 9; 2879 memset(buf, 0, len - 1); 2880 buf[len - 1] = type; 2881 sshbuf_reset(ssh->state->outgoing_packet); 2882 return sshbuf_put(ssh->state->outgoing_packet, buf, len); 2883} 2884 2885/* send it */ 2886 2887int 2888sshpkt_send(struct ssh *ssh) 2889{ 2890 if (compat20) 2891 return ssh_packet_send2(ssh); 2892 else 2893 return ssh_packet_send1(ssh); 2894} 2895 2896int 2897sshpkt_disconnect(struct ssh *ssh, const char *fmt,...) 2898{ 2899 char buf[1024]; 2900 va_list args; 2901 int r; 2902 2903 va_start(args, fmt); 2904 vsnprintf(buf, sizeof(buf), fmt, args); 2905 va_end(args); 2906 2907 if (compat20) { 2908 if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 || 2909 (r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_PROTOCOL_ERROR)) != 0 || 2910 (r = sshpkt_put_cstring(ssh, buf)) != 0 || 2911 (r = sshpkt_put_cstring(ssh, "")) != 0 || 2912 (r = sshpkt_send(ssh)) != 0) 2913 return r; 2914 } else { 2915 if ((r = sshpkt_start(ssh, SSH_MSG_DISCONNECT)) != 0 || 2916 (r = sshpkt_put_cstring(ssh, buf)) != 0 || 2917 (r = sshpkt_send(ssh)) != 0) 2918 return r; 2919 } 2920 return 0; 2921} 2922 2923/* roundup current message to pad bytes */ 2924int 2925sshpkt_add_padding(struct ssh *ssh, u_char pad) 2926{ 2927 ssh->state->extra_pad = pad; 2928 return 0; 2929} 2930