packet.c revision 1.16
1/* $NetBSD: packet.c,v 1.16 2015/04/03 23:58:19 christos Exp $ */ 2/* $OpenBSD: packet.c,v 1.208 2015/02/13 18:57:00 markus Exp $ */ 3/* 4 * Author: Tatu Ylonen <ylo@cs.hut.fi> 5 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 6 * All rights reserved 7 * This file contains code implementing the packet protocol and communication 8 * with the other side. This same code is used both on client and server side. 9 * 10 * As far as I am concerned, the code I have written for this software 11 * can be used freely for any purpose. Any derived versions of this 12 * software must be clearly marked as such, and if the derived work is 13 * incompatible with the protocol description in the RFC file, it must be 14 * called by a name other than "ssh" or "Secure Shell". 15 * 16 * 17 * SSH2 packet format added by Markus Friedl. 18 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. 19 * 20 * Redistribution and use in source and binary forms, with or without 21 * modification, are permitted provided that the following conditions 22 * are met: 23 * 1. Redistributions of source code must retain the above copyright 24 * notice, this list of conditions and the following disclaimer. 25 * 2. Redistributions in binary form must reproduce the above copyright 26 * notice, this list of conditions and the following disclaimer in the 27 * documentation and/or other materials provided with the distribution. 28 * 29 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 30 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 31 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 32 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 33 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 34 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 38 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 39 */ 40 41#include "includes.h" 42__RCSID("$NetBSD: packet.c,v 1.16 2015/04/03 23:58:19 christos Exp $"); 43#include <sys/param.h> /* MIN roundup */ 44#include <sys/types.h> 45#include <sys/queue.h> 46#include <sys/socket.h> 47#include <sys/time.h> 48#include <netinet/in.h> 49#include <netinet/ip.h> 50 51#include <errno.h> 52#include <stdarg.h> 53#include <stdio.h> 54#include <stdlib.h> 55#include <string.h> 56#include <unistd.h> 57#include <limits.h> 58#include <signal.h> 59#include <time.h> 60 61#include <zlib.h> 62 63#include "buffer.h" /* typedefs XXX */ 64#include "key.h" /* typedefs XXX */ 65 66#include "xmalloc.h" 67#include "crc32.h" 68#include "deattack.h" 69#include "compat.h" 70#include "ssh1.h" 71#include "ssh2.h" 72#include "cipher.h" 73#include "sshkey.h" 74#include "kex.h" 75#include "digest.h" 76#include "mac.h" 77#include "log.h" 78#include "canohost.h" 79#include "misc.h" 80#include "channels.h" 81#include "ssh.h" 82#include "packet.h" 83#include "roaming.h" 84#include "ssherr.h" 85#include "sshbuf.h" 86 87#ifdef PACKET_DEBUG 88#define DBG(x) x 89#else 90#define DBG(x) 91#endif 92 93#define PACKET_MAX_SIZE (256 * 1024) 94 95struct packet_state { 96 u_int32_t seqnr; 97 u_int32_t packets; 98 u_int64_t blocks; 99 u_int64_t bytes; 100}; 101 102struct packet { 103 TAILQ_ENTRY(packet) next; 104 u_char type; 105 struct sshbuf *payload; 106}; 107 108struct session_state { 109 /* 110 * This variable contains the file descriptors used for 111 * communicating with the other side. connection_in is used for 112 * reading; connection_out for writing. These can be the same 113 * descriptor, in which case it is assumed to be a socket. 114 */ 115 int connection_in; 116 int connection_out; 117 118 /* Protocol flags for the remote side. */ 119 u_int remote_protocol_flags; 120 121 /* Encryption context for receiving data. Only used for decryption. */ 122 struct sshcipher_ctx receive_context; 123 124 /* Encryption context for sending data. Only used for encryption. */ 125 struct sshcipher_ctx send_context; 126 127 /* Buffer for raw input data from the socket. */ 128 struct sshbuf *input; 129 130 /* Buffer for raw output data going to the socket. */ 131 struct sshbuf *output; 132 133 /* Buffer for the partial outgoing packet being constructed. */ 134 struct sshbuf *outgoing_packet; 135 136 /* Buffer for the incoming packet currently being processed. */ 137 struct sshbuf *incoming_packet; 138 139 /* Scratch buffer for packet compression/decompression. */ 140 struct sshbuf *compression_buffer; 141 142 /* Incoming/outgoing compression dictionaries */ 143 z_stream compression_in_stream; 144 z_stream compression_out_stream; 145 int compression_in_started; 146 int compression_out_started; 147 int compression_in_failures; 148 int compression_out_failures; 149 150 /* 151 * Flag indicating whether packet compression/decompression is 152 * enabled. 153 */ 154 int packet_compression; 155 156 /* default maximum packet size */ 157 u_int max_packet_size; 158 159 /* Flag indicating whether this module has been initialized. */ 160 int initialized; 161 162 /* Set to true if the connection is interactive. */ 163 int interactive_mode; 164 165 /* Set to true if we are the server side. */ 166 int server_side; 167 168 /* Set to true if we are authenticated. */ 169 int after_authentication; 170 171 int keep_alive_timeouts; 172 173 /* The maximum time that we will wait to send or receive a packet */ 174 int packet_timeout_ms; 175 176 /* Session key information for Encryption and MAC */ 177 struct newkeys *newkeys[MODE_MAX]; 178 struct packet_state p_read, p_send; 179 180 /* Volume-based rekeying */ 181 u_int64_t max_blocks_in, max_blocks_out; 182 u_int32_t rekey_limit; 183 184 /* Time-based rekeying */ 185 u_int32_t rekey_interval; /* how often in seconds */ 186 time_t rekey_time; /* time of last rekeying */ 187 188 /* Session key for protocol v1 */ 189 u_char ssh1_key[SSH_SESSION_KEY_LENGTH]; 190 u_int ssh1_keylen; 191 192 /* roundup current message to extra_pad bytes */ 193 u_char extra_pad; 194 195 /* XXX discard incoming data after MAC error */ 196 u_int packet_discard; 197 struct sshmac *packet_discard_mac; 198 199 /* Used in packet_read_poll2() */ 200 u_int packlen; 201 202 /* Used in packet_send2 */ 203 int rekeying; 204 205 /* Used in packet_set_interactive */ 206 int set_interactive_called; 207 208 /* Used in packet_set_maxsize */ 209 int set_maxsize_called; 210 211 /* One-off warning about weak ciphers */ 212 int cipher_warning_done; 213 214 /* SSH1 CRC compensation attack detector */ 215 struct deattack_ctx deattack; 216 217 TAILQ_HEAD(, packet) outgoing; 218}; 219 220struct ssh * 221ssh_alloc_session_state(void) 222{ 223 struct ssh *ssh = NULL; 224 struct session_state *state = NULL; 225 226 if ((ssh = calloc(1, sizeof(*ssh))) == NULL || 227 (state = calloc(1, sizeof(*state))) == NULL || 228 (state->input = sshbuf_new()) == NULL || 229 (state->output = sshbuf_new()) == NULL || 230 (state->outgoing_packet = sshbuf_new()) == NULL || 231 (state->incoming_packet = sshbuf_new()) == NULL) 232 goto fail; 233 TAILQ_INIT(&state->outgoing); 234 TAILQ_INIT(&ssh->private_keys); 235 TAILQ_INIT(&ssh->public_keys); 236 state->connection_in = -1; 237 state->connection_out = -1; 238 state->max_packet_size = 32768; 239 state->packet_timeout_ms = -1; 240 state->p_send.packets = state->p_read.packets = 0; 241 state->initialized = 1; 242 /* 243 * ssh_packet_send2() needs to queue packets until 244 * we've done the initial key exchange. 245 */ 246 state->rekeying = 1; 247 ssh->state = state; 248 return ssh; 249 fail: 250 if (state) { 251 sshbuf_free(state->input); 252 sshbuf_free(state->output); 253 sshbuf_free(state->incoming_packet); 254 sshbuf_free(state->outgoing_packet); 255 free(state); 256 } 257 free(ssh); 258 return NULL; 259} 260 261/* 262 * Sets the descriptors used for communication. Disables encryption until 263 * packet_set_encryption_key is called. 264 */ 265struct ssh * 266ssh_packet_set_connection(struct ssh *ssh, int fd_in, int fd_out) 267{ 268 struct session_state *state; 269 const struct sshcipher *none = cipher_by_name("none"); 270 int r; 271 272 if (none == NULL) { 273 error("%s: cannot load cipher 'none'", __func__); 274 return NULL; 275 } 276 if (ssh == NULL) 277 ssh = ssh_alloc_session_state(); 278 if (ssh == NULL) { 279 error("%s: cound not allocate state", __func__); 280 return NULL; 281 } 282 state = ssh->state; 283 state->connection_in = fd_in; 284 state->connection_out = fd_out; 285 if ((r = cipher_init(&state->send_context, none, 286 (const u_char *)"", 0, NULL, 0, CIPHER_ENCRYPT)) != 0 || 287 (r = cipher_init(&state->receive_context, none, 288 (const u_char *)"", 0, NULL, 0, CIPHER_DECRYPT)) != 0) { 289 error("%s: cipher_init failed: %s", __func__, ssh_err(r)); 290 return NULL; 291 } 292 state->newkeys[MODE_IN] = state->newkeys[MODE_OUT] = NULL; 293 deattack_init(&state->deattack); 294 /* 295 * Cache the IP address of the remote connection for use in error 296 * messages that might be generated after the connection has closed. 297 */ 298 (void)ssh_remote_ipaddr(ssh); 299 return ssh; 300} 301 302void 303ssh_packet_set_timeout(struct ssh *ssh, int timeout, int count) 304{ 305 struct session_state *state = ssh->state; 306 307 if (timeout <= 0 || count <= 0) { 308 state->packet_timeout_ms = -1; 309 return; 310 } 311 if ((INT_MAX / 1000) / count < timeout) 312 state->packet_timeout_ms = INT_MAX; 313 else 314 state->packet_timeout_ms = timeout * count * 1000; 315} 316 317int 318ssh_packet_stop_discard(struct ssh *ssh) 319{ 320 struct session_state *state = ssh->state; 321 int r; 322 323 if (state->packet_discard_mac) { 324 char buf[1024]; 325 326 memset(buf, 'a', sizeof(buf)); 327 while (sshbuf_len(state->incoming_packet) < 328 PACKET_MAX_SIZE) 329 if ((r = sshbuf_put(state->incoming_packet, buf, 330 sizeof(buf))) != 0) 331 return r; 332 (void) mac_compute(state->packet_discard_mac, 333 state->p_read.seqnr, 334 sshbuf_ptr(state->incoming_packet), PACKET_MAX_SIZE, 335 NULL, 0); 336 } 337 logit("Finished discarding for %.200s", ssh_remote_ipaddr(ssh)); 338 return SSH_ERR_MAC_INVALID; 339} 340 341static int 342ssh_packet_start_discard(struct ssh *ssh, struct sshenc *enc, 343 struct sshmac *mac, u_int packet_length, u_int discard) 344{ 345 struct session_state *state = ssh->state; 346 int r; 347 348 if (enc == NULL || !cipher_is_cbc(enc->cipher) || (mac && mac->etm)) { 349 if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0) 350 return r; 351 return SSH_ERR_MAC_INVALID; 352 } 353 if (packet_length != PACKET_MAX_SIZE && mac && mac->enabled) 354 state->packet_discard_mac = mac; 355 if (sshbuf_len(state->input) >= discard && 356 (r = ssh_packet_stop_discard(ssh)) != 0) 357 return r; 358 state->packet_discard = discard - sshbuf_len(state->input); 359 return 0; 360} 361 362/* Returns 1 if remote host is connected via socket, 0 if not. */ 363 364int 365ssh_packet_connection_is_on_socket(struct ssh *ssh) 366{ 367 struct session_state *state = ssh->state; 368 struct sockaddr_storage from, to; 369 socklen_t fromlen, tolen; 370 371 /* filedescriptors in and out are the same, so it's a socket */ 372 if (state->connection_in == state->connection_out) 373 return 1; 374 fromlen = sizeof(from); 375 memset(&from, 0, sizeof(from)); 376 if (getpeername(state->connection_in, (struct sockaddr *)&from, 377 &fromlen) < 0) 378 return 0; 379 tolen = sizeof(to); 380 memset(&to, 0, sizeof(to)); 381 if (getpeername(state->connection_out, (struct sockaddr *)&to, 382 &tolen) < 0) 383 return 0; 384 if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0) 385 return 0; 386 if (from.ss_family != AF_INET && from.ss_family != AF_INET6) 387 return 0; 388 return 1; 389} 390 391void 392ssh_packet_get_bytes(struct ssh *ssh, u_int64_t *ibytes, u_int64_t *obytes) 393{ 394 if (ibytes) 395 *ibytes = ssh->state->p_read.bytes; 396 if (obytes) 397 *obytes = ssh->state->p_send.bytes; 398} 399 400int 401ssh_packet_connection_af(struct ssh *ssh) 402{ 403 struct sockaddr_storage to; 404 socklen_t tolen = sizeof(to); 405 406 memset(&to, 0, sizeof(to)); 407 if (getsockname(ssh->state->connection_out, (struct sockaddr *)&to, 408 &tolen) < 0) 409 return 0; 410 return to.ss_family; 411} 412 413/* Sets the connection into non-blocking mode. */ 414 415void 416ssh_packet_set_nonblocking(struct ssh *ssh) 417{ 418 /* Set the socket into non-blocking mode. */ 419 set_nonblock(ssh->state->connection_in); 420 421 if (ssh->state->connection_out != ssh->state->connection_in) 422 set_nonblock(ssh->state->connection_out); 423} 424 425/* Returns the socket used for reading. */ 426 427int 428ssh_packet_get_connection_in(struct ssh *ssh) 429{ 430 return ssh->state->connection_in; 431} 432 433/* Returns the descriptor used for writing. */ 434 435int 436ssh_packet_get_connection_out(struct ssh *ssh) 437{ 438 return ssh->state->connection_out; 439} 440 441/* 442 * Returns the IP-address of the remote host as a string. The returned 443 * string must not be freed. 444 */ 445 446const char * 447ssh_remote_ipaddr(struct ssh *ssh) 448{ 449 /* Check whether we have cached the ipaddr. */ 450 if (ssh->remote_ipaddr == NULL) 451 ssh->remote_ipaddr = ssh_packet_connection_is_on_socket(ssh) ? 452 get_peer_ipaddr(ssh->state->connection_in) : 453 strdup("UNKNOWN"); 454 if (ssh->remote_ipaddr == NULL) 455 return "UNKNOWN"; 456 return ssh->remote_ipaddr; 457} 458 459/* Closes the connection and clears and frees internal data structures. */ 460 461void 462ssh_packet_close(struct ssh *ssh) 463{ 464 struct session_state *state = ssh->state; 465 int r; 466 u_int mode; 467 468 if (!state->initialized) 469 return; 470 state->initialized = 0; 471 if (state->connection_in == state->connection_out) { 472 shutdown(state->connection_out, SHUT_RDWR); 473 close(state->connection_out); 474 } else { 475 close(state->connection_in); 476 close(state->connection_out); 477 } 478 sshbuf_free(state->input); 479 sshbuf_free(state->output); 480 sshbuf_free(state->outgoing_packet); 481 sshbuf_free(state->incoming_packet); 482 for (mode = 0; mode < MODE_MAX; mode++) 483 kex_free_newkeys(state->newkeys[mode]); 484 if (state->compression_buffer) { 485 sshbuf_free(state->compression_buffer); 486 if (state->compression_out_started) { 487 z_streamp stream = &state->compression_out_stream; 488 debug("compress outgoing: " 489 "raw data %llu, compressed %llu, factor %.2f", 490 (unsigned long long)stream->total_in, 491 (unsigned long long)stream->total_out, 492 stream->total_in == 0 ? 0.0 : 493 (double) stream->total_out / stream->total_in); 494 if (state->compression_out_failures == 0) 495 deflateEnd(stream); 496 } 497 if (state->compression_in_started) { 498 z_streamp stream = &state->compression_out_stream; 499 debug("compress incoming: " 500 "raw data %llu, compressed %llu, factor %.2f", 501 (unsigned long long)stream->total_out, 502 (unsigned long long)stream->total_in, 503 stream->total_out == 0 ? 0.0 : 504 (double) stream->total_in / stream->total_out); 505 if (state->compression_in_failures == 0) 506 inflateEnd(stream); 507 } 508 } 509 if ((r = cipher_cleanup(&state->send_context)) != 0) 510 error("%s: cipher_cleanup failed: %s", __func__, ssh_err(r)); 511 if ((r = cipher_cleanup(&state->receive_context)) != 0) 512 error("%s: cipher_cleanup failed: %s", __func__, ssh_err(r)); 513 if (ssh->remote_ipaddr) { 514 free(ssh->remote_ipaddr); 515 ssh->remote_ipaddr = NULL; 516 } 517 free(ssh->state); 518 ssh->state = NULL; 519} 520 521/* Sets remote side protocol flags. */ 522 523void 524ssh_packet_set_protocol_flags(struct ssh *ssh, u_int protocol_flags) 525{ 526 ssh->state->remote_protocol_flags = protocol_flags; 527} 528 529/* Returns the remote protocol flags set earlier by the above function. */ 530 531u_int 532ssh_packet_get_protocol_flags(struct ssh *ssh) 533{ 534 return ssh->state->remote_protocol_flags; 535} 536 537/* 538 * Starts packet compression from the next packet on in both directions. 539 * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip. 540 */ 541 542static int 543ssh_packet_init_compression(struct ssh *ssh) 544{ 545 if (!ssh->state->compression_buffer && 546 ((ssh->state->compression_buffer = sshbuf_new()) == NULL)) 547 return SSH_ERR_ALLOC_FAIL; 548 return 0; 549} 550 551static int 552start_compression_out(struct ssh *ssh, int level) 553{ 554 if (level < 1 || level > 9) 555 return SSH_ERR_INVALID_ARGUMENT; 556 debug("Enabling compression at level %d.", level); 557 if (ssh->state->compression_out_started == 1) 558 deflateEnd(&ssh->state->compression_out_stream); 559 switch (deflateInit(&ssh->state->compression_out_stream, level)) { 560 case Z_OK: 561 ssh->state->compression_out_started = 1; 562 break; 563 case Z_MEM_ERROR: 564 return SSH_ERR_ALLOC_FAIL; 565 default: 566 return SSH_ERR_INTERNAL_ERROR; 567 } 568 return 0; 569} 570 571static int 572start_compression_in(struct ssh *ssh) 573{ 574 if (ssh->state->compression_in_started == 1) 575 inflateEnd(&ssh->state->compression_in_stream); 576 switch (inflateInit(&ssh->state->compression_in_stream)) { 577 case Z_OK: 578 ssh->state->compression_in_started = 1; 579 break; 580 case Z_MEM_ERROR: 581 return SSH_ERR_ALLOC_FAIL; 582 default: 583 return SSH_ERR_INTERNAL_ERROR; 584 } 585 return 0; 586} 587 588int 589ssh_packet_start_compression(struct ssh *ssh, int level) 590{ 591 int r; 592 593 if (ssh->state->packet_compression && !compat20) 594 return SSH_ERR_INTERNAL_ERROR; 595 ssh->state->packet_compression = 1; 596 if ((r = ssh_packet_init_compression(ssh)) != 0 || 597 (r = start_compression_in(ssh)) != 0 || 598 (r = start_compression_out(ssh, level)) != 0) 599 return r; 600 return 0; 601} 602 603/* XXX remove need for separate compression buffer */ 604static int 605compress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out) 606{ 607 u_char buf[4096]; 608 int r, status; 609 610 if (ssh->state->compression_out_started != 1) 611 return SSH_ERR_INTERNAL_ERROR; 612 613 /* This case is not handled below. */ 614 if (sshbuf_len(in) == 0) 615 return 0; 616 617 /* Input is the contents of the input buffer. */ 618 if ((ssh->state->compression_out_stream.next_in = 619 sshbuf_mutable_ptr(in)) == NULL) 620 return SSH_ERR_INTERNAL_ERROR; 621 ssh->state->compression_out_stream.avail_in = sshbuf_len(in); 622 623 /* Loop compressing until deflate() returns with avail_out != 0. */ 624 do { 625 /* Set up fixed-size output buffer. */ 626 ssh->state->compression_out_stream.next_out = buf; 627 ssh->state->compression_out_stream.avail_out = sizeof(buf); 628 629 /* Compress as much data into the buffer as possible. */ 630 status = deflate(&ssh->state->compression_out_stream, 631 Z_PARTIAL_FLUSH); 632 switch (status) { 633 case Z_MEM_ERROR: 634 return SSH_ERR_ALLOC_FAIL; 635 case Z_OK: 636 /* Append compressed data to output_buffer. */ 637 if ((r = sshbuf_put(out, buf, sizeof(buf) - 638 ssh->state->compression_out_stream.avail_out)) != 0) 639 return r; 640 break; 641 case Z_STREAM_ERROR: 642 default: 643 ssh->state->compression_out_failures++; 644 return SSH_ERR_INVALID_FORMAT; 645 } 646 } while (ssh->state->compression_out_stream.avail_out == 0); 647 return 0; 648} 649 650static int 651uncompress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out) 652{ 653 u_char buf[4096]; 654 int r, status; 655 656 if (ssh->state->compression_in_started != 1) 657 return SSH_ERR_INTERNAL_ERROR; 658 659 if ((ssh->state->compression_in_stream.next_in = 660 sshbuf_mutable_ptr(in)) == NULL) 661 return SSH_ERR_INTERNAL_ERROR; 662 ssh->state->compression_in_stream.avail_in = sshbuf_len(in); 663 664 for (;;) { 665 /* Set up fixed-size output buffer. */ 666 ssh->state->compression_in_stream.next_out = buf; 667 ssh->state->compression_in_stream.avail_out = sizeof(buf); 668 669 status = inflate(&ssh->state->compression_in_stream, 670 Z_PARTIAL_FLUSH); 671 switch (status) { 672 case Z_OK: 673 if ((r = sshbuf_put(out, buf, sizeof(buf) - 674 ssh->state->compression_in_stream.avail_out)) != 0) 675 return r; 676 break; 677 case Z_BUF_ERROR: 678 /* 679 * Comments in zlib.h say that we should keep calling 680 * inflate() until we get an error. This appears to 681 * be the error that we get. 682 */ 683 return 0; 684 case Z_DATA_ERROR: 685 return SSH_ERR_INVALID_FORMAT; 686 case Z_MEM_ERROR: 687 return SSH_ERR_ALLOC_FAIL; 688 case Z_STREAM_ERROR: 689 default: 690 ssh->state->compression_in_failures++; 691 return SSH_ERR_INTERNAL_ERROR; 692 } 693 } 694 /* NOTREACHED */ 695} 696 697/* Serialise compression state into a blob for privsep */ 698static int 699ssh_packet_get_compress_state(struct sshbuf *m, struct ssh *ssh) 700{ 701 struct session_state *state = ssh->state; 702 struct sshbuf *b; 703 int r; 704 705 if ((b = sshbuf_new()) == NULL) 706 return SSH_ERR_ALLOC_FAIL; 707 if (state->compression_in_started) { 708 if ((r = sshbuf_put_string(b, &state->compression_in_stream, 709 sizeof(state->compression_in_stream))) != 0) 710 goto out; 711 } else if ((r = sshbuf_put_string(b, NULL, 0)) != 0) 712 goto out; 713 if (state->compression_out_started) { 714 if ((r = sshbuf_put_string(b, &state->compression_out_stream, 715 sizeof(state->compression_out_stream))) != 0) 716 goto out; 717 } else if ((r = sshbuf_put_string(b, NULL, 0)) != 0) 718 goto out; 719 r = sshbuf_put_stringb(m, b); 720 out: 721 sshbuf_free(b); 722 return r; 723} 724 725/* Deserialise compression state from a blob for privsep */ 726static int 727ssh_packet_set_compress_state(struct ssh *ssh, struct sshbuf *m) 728{ 729 struct session_state *state = ssh->state; 730 struct sshbuf *b = NULL; 731 int r; 732 const u_char *inblob, *outblob; 733 size_t inl, outl; 734 735 if ((r = sshbuf_froms(m, &b)) != 0) 736 goto out; 737 if ((r = sshbuf_get_string_direct(b, &inblob, &inl)) != 0 || 738 (r = sshbuf_get_string_direct(b, &outblob, &outl)) != 0) 739 goto out; 740 if (inl == 0) 741 state->compression_in_started = 0; 742 else if (inl != sizeof(state->compression_in_stream)) { 743 r = SSH_ERR_INTERNAL_ERROR; 744 goto out; 745 } else { 746 state->compression_in_started = 1; 747 memcpy(&state->compression_in_stream, inblob, inl); 748 } 749 if (outl == 0) 750 state->compression_out_started = 0; 751 else if (outl != sizeof(state->compression_out_stream)) { 752 r = SSH_ERR_INTERNAL_ERROR; 753 goto out; 754 } else { 755 state->compression_out_started = 1; 756 memcpy(&state->compression_out_stream, outblob, outl); 757 } 758 r = 0; 759 out: 760 sshbuf_free(b); 761 return r; 762} 763 764void 765ssh_packet_set_compress_hooks(struct ssh *ssh, void *ctx, 766 void *(*allocfunc)(void *, u_int, u_int), 767 void (*freefunc)(void *, void *)) 768{ 769 ssh->state->compression_out_stream.zalloc = (alloc_func)allocfunc; 770 ssh->state->compression_out_stream.zfree = (free_func)freefunc; 771 ssh->state->compression_out_stream.opaque = ctx; 772 ssh->state->compression_in_stream.zalloc = (alloc_func)allocfunc; 773 ssh->state->compression_in_stream.zfree = (free_func)freefunc; 774 ssh->state->compression_in_stream.opaque = ctx; 775} 776 777/* 778 * Causes any further packets to be encrypted using the given key. The same 779 * key is used for both sending and reception. However, both directions are 780 * encrypted independently of each other. 781 */ 782 783#ifdef WITH_OPENSSL 784void 785ssh_packet_set_encryption_key(struct ssh *ssh, const u_char *key, u_int keylen, int number) 786{ 787 struct session_state *state = ssh->state; 788 const struct sshcipher *cipher = cipher_by_number(number); 789 int r; 790 const char *wmsg; 791 792 if (cipher == NULL) 793 fatal("%s: unknown cipher number %d", __func__, number); 794 if (keylen < 20) 795 fatal("%s: keylen too small: %d", __func__, keylen); 796 if (keylen > SSH_SESSION_KEY_LENGTH) 797 fatal("%s: keylen too big: %d", __func__, keylen); 798 memcpy(state->ssh1_key, key, keylen); 799 state->ssh1_keylen = keylen; 800 if ((r = cipher_init(&state->send_context, cipher, key, keylen, 801 NULL, 0, CIPHER_ENCRYPT)) != 0 || 802 (r = cipher_init(&state->receive_context, cipher, key, keylen, 803 NULL, 0, CIPHER_DECRYPT) != 0)) 804 fatal("%s: cipher_init failed: %s", __func__, ssh_err(r)); 805 if (!state->cipher_warning_done && 806 ((wmsg = cipher_warning_message(&state->send_context)) != NULL || 807 (wmsg = cipher_warning_message(&state->send_context)) != NULL)) { 808 error("Warning: %s", wmsg); 809 state->cipher_warning_done = 1; 810 } 811} 812#endif 813 814/* 815 * Finalizes and sends the packet. If the encryption key has been set, 816 * encrypts the packet before sending. 817 */ 818 819int 820ssh_packet_send1(struct ssh *ssh) 821{ 822 struct session_state *state = ssh->state; 823 u_char buf[8], *cp; 824 int r, padding, len; 825 u_int checksum; 826 827 /* 828 * If using packet compression, compress the payload of the outgoing 829 * packet. 830 */ 831 if (state->packet_compression) { 832 sshbuf_reset(state->compression_buffer); 833 /* Skip padding. */ 834 if ((r = sshbuf_consume(state->outgoing_packet, 8)) != 0) 835 goto out; 836 /* padding */ 837 if ((r = sshbuf_put(state->compression_buffer, 838 "\0\0\0\0\0\0\0\0", 8)) != 0) 839 goto out; 840 if ((r = compress_buffer(ssh, state->outgoing_packet, 841 state->compression_buffer)) != 0) 842 goto out; 843 sshbuf_reset(state->outgoing_packet); 844 if ((r = sshbuf_putb(state->outgoing_packet, 845 state->compression_buffer)) != 0) 846 goto out; 847 } 848 /* Compute packet length without padding (add checksum, remove padding). */ 849 len = sshbuf_len(state->outgoing_packet) + 4 - 8; 850 851 /* Insert padding. Initialized to zero in packet_start1() */ 852 padding = 8 - len % 8; 853 if (!state->send_context.plaintext) { 854 cp = sshbuf_mutable_ptr(state->outgoing_packet); 855 if (cp == NULL) { 856 r = SSH_ERR_INTERNAL_ERROR; 857 goto out; 858 } 859 arc4random_buf(cp + 8 - padding, padding); 860 } 861 if ((r = sshbuf_consume(state->outgoing_packet, 8 - padding)) != 0) 862 goto out; 863 864 /* Add check bytes. */ 865 checksum = ssh_crc32(sshbuf_ptr(state->outgoing_packet), 866 sshbuf_len(state->outgoing_packet)); 867 POKE_U32(buf, checksum); 868 if ((r = sshbuf_put(state->outgoing_packet, buf, 4)) != 0) 869 goto out; 870 871#ifdef PACKET_DEBUG 872 fprintf(stderr, "packet_send plain: "); 873 sshbuf_dump(state->outgoing_packet, stderr); 874#endif 875 876 /* Append to output. */ 877 POKE_U32(buf, len); 878 if ((r = sshbuf_put(state->output, buf, 4)) != 0) 879 goto out; 880 if ((r = sshbuf_reserve(state->output, 881 sshbuf_len(state->outgoing_packet), &cp)) != 0) 882 goto out; 883 if ((r = cipher_crypt(&state->send_context, 0, cp, 884 sshbuf_ptr(state->outgoing_packet), 885 sshbuf_len(state->outgoing_packet), 0, 0)) != 0) 886 goto out; 887 888#ifdef PACKET_DEBUG 889 fprintf(stderr, "encrypted: "); 890 sshbuf_dump(state->output, stderr); 891#endif 892 state->p_send.packets++; 893 state->p_send.bytes += len + 894 sshbuf_len(state->outgoing_packet); 895 sshbuf_reset(state->outgoing_packet); 896 897 /* 898 * Note that the packet is now only buffered in output. It won't be 899 * actually sent until ssh_packet_write_wait or ssh_packet_write_poll 900 * is called. 901 */ 902 r = 0; 903 out: 904 return r; 905} 906 907int 908ssh_set_newkeys(struct ssh *ssh, int mode) 909{ 910 struct session_state *state = ssh->state; 911 struct sshenc *enc; 912 struct sshmac *mac; 913 struct sshcomp *comp; 914 struct sshcipher_ctx *cc; 915 u_int64_t *max_blocks; 916 const char *wmsg; 917 int r, crypt_type; 918 919 debug2("set_newkeys: mode %d", mode); 920 921 if (mode == MODE_OUT) { 922 cc = &state->send_context; 923 crypt_type = CIPHER_ENCRYPT; 924 state->p_send.packets = state->p_send.blocks = 0; 925 max_blocks = &state->max_blocks_out; 926 } else { 927 cc = &state->receive_context; 928 crypt_type = CIPHER_DECRYPT; 929 state->p_read.packets = state->p_read.blocks = 0; 930 max_blocks = &state->max_blocks_in; 931 } 932 if (state->newkeys[mode] != NULL) { 933 debug("set_newkeys: rekeying"); 934 if ((r = cipher_cleanup(cc)) != 0) 935 return r; 936 enc = &state->newkeys[mode]->enc; 937 mac = &state->newkeys[mode]->mac; 938 comp = &state->newkeys[mode]->comp; 939 mac_clear(mac); 940 explicit_bzero(enc->iv, enc->iv_len); 941 explicit_bzero(enc->key, enc->key_len); 942 explicit_bzero(mac->key, mac->key_len); 943 free(enc->name); 944 free(enc->iv); 945 free(enc->key); 946 free(mac->name); 947 free(mac->key); 948 free(comp->name); 949 free(state->newkeys[mode]); 950 } 951 /* move newkeys from kex to state */ 952 if ((state->newkeys[mode] = ssh->kex->newkeys[mode]) == NULL) 953 return SSH_ERR_INTERNAL_ERROR; 954 ssh->kex->newkeys[mode] = NULL; 955 enc = &state->newkeys[mode]->enc; 956 mac = &state->newkeys[mode]->mac; 957 comp = &state->newkeys[mode]->comp; 958 if (cipher_authlen(enc->cipher) == 0) { 959 if ((r = mac_init(mac)) != 0) 960 return r; 961 } 962 mac->enabled = 1; 963 DBG(debug("cipher_init_context: %d", mode)); 964 if ((r = cipher_init(cc, enc->cipher, enc->key, enc->key_len, 965 enc->iv, enc->iv_len, crypt_type)) != 0) 966 return r; 967 if (!state->cipher_warning_done && 968 (wmsg = cipher_warning_message(cc)) != NULL) { 969 error("Warning: %s", wmsg); 970 state->cipher_warning_done = 1; 971 } 972 /* Deleting the keys does not gain extra security */ 973 /* explicit_bzero(enc->iv, enc->block_size); 974 explicit_bzero(enc->key, enc->key_len); 975 explicit_bzero(mac->key, mac->key_len); */ 976 if ((comp->type == COMP_ZLIB || 977 (comp->type == COMP_DELAYED && 978 state->after_authentication)) && comp->enabled == 0) { 979 if ((r = ssh_packet_init_compression(ssh)) < 0) 980 return r; 981 if (mode == MODE_OUT) { 982 if ((r = start_compression_out(ssh, 6)) != 0) 983 return r; 984 } else { 985 if ((r = start_compression_in(ssh)) != 0) 986 return r; 987 } 988 comp->enabled = 1; 989 } 990 /* 991 * The 2^(blocksize*2) limit is too expensive for 3DES, 992 * blowfish, etc, so enforce a 1GB limit for small blocksizes. 993 */ 994 if (enc->block_size >= 16) 995 *max_blocks = (u_int64_t)1 << (enc->block_size*2); 996 else 997 *max_blocks = ((u_int64_t)1 << 30) / enc->block_size; 998 if (state->rekey_limit) 999 *max_blocks = MIN(*max_blocks, 1000 state->rekey_limit / enc->block_size); 1001 return 0; 1002} 1003 1004/* 1005 * Delayed compression for SSH2 is enabled after authentication: 1006 * This happens on the server side after a SSH2_MSG_USERAUTH_SUCCESS is sent, 1007 * and on the client side after a SSH2_MSG_USERAUTH_SUCCESS is received. 1008 */ 1009static int 1010ssh_packet_enable_delayed_compress(struct ssh *ssh) 1011{ 1012 struct session_state *state = ssh->state; 1013 struct sshcomp *comp = NULL; 1014 int r, mode; 1015 1016 /* 1017 * Remember that we are past the authentication step, so rekeying 1018 * with COMP_DELAYED will turn on compression immediately. 1019 */ 1020 state->after_authentication = 1; 1021 for (mode = 0; mode < MODE_MAX; mode++) { 1022 /* protocol error: USERAUTH_SUCCESS received before NEWKEYS */ 1023 if (state->newkeys[mode] == NULL) 1024 continue; 1025 comp = &state->newkeys[mode]->comp; 1026 if (comp && !comp->enabled && comp->type == COMP_DELAYED) { 1027 if ((r = ssh_packet_init_compression(ssh)) != 0) 1028 return r; 1029 if (mode == MODE_OUT) { 1030 if ((r = start_compression_out(ssh, 6)) != 0) 1031 return r; 1032 } else { 1033 if ((r = start_compression_in(ssh)) != 0) 1034 return r; 1035 } 1036 comp->enabled = 1; 1037 } 1038 } 1039 return 0; 1040} 1041 1042/* 1043 * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue) 1044 */ 1045int 1046ssh_packet_send2_wrapped(struct ssh *ssh) 1047{ 1048 struct session_state *state = ssh->state; 1049 u_char type, *cp, macbuf[SSH_DIGEST_MAX_LENGTH]; 1050 u_char padlen, pad = 0; 1051 u_int authlen = 0, aadlen = 0; 1052 u_int len; 1053 struct sshenc *enc = NULL; 1054 struct sshmac *mac = NULL; 1055 struct sshcomp *comp = NULL; 1056 int r, block_size; 1057 1058 if (state->newkeys[MODE_OUT] != NULL) { 1059 enc = &state->newkeys[MODE_OUT]->enc; 1060 mac = &state->newkeys[MODE_OUT]->mac; 1061 comp = &state->newkeys[MODE_OUT]->comp; 1062 /* disable mac for authenticated encryption */ 1063 if ((authlen = cipher_authlen(enc->cipher)) != 0) 1064 mac = NULL; 1065 } 1066 block_size = enc ? enc->block_size : 8; 1067 aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0; 1068 1069 type = (sshbuf_ptr(state->outgoing_packet))[5]; 1070 1071#ifdef PACKET_DEBUG 1072 fprintf(stderr, "plain: "); 1073 sshbuf_dump(state->outgoing_packet, stderr); 1074#endif 1075 1076 if (comp && comp->enabled) { 1077 len = sshbuf_len(state->outgoing_packet); 1078 /* skip header, compress only payload */ 1079 if ((r = sshbuf_consume(state->outgoing_packet, 5)) != 0) 1080 goto out; 1081 sshbuf_reset(state->compression_buffer); 1082 if ((r = compress_buffer(ssh, state->outgoing_packet, 1083 state->compression_buffer)) != 0) 1084 goto out; 1085 sshbuf_reset(state->outgoing_packet); 1086 if ((r = sshbuf_put(state->outgoing_packet, 1087 "\0\0\0\0\0", 5)) != 0 || 1088 (r = sshbuf_putb(state->outgoing_packet, 1089 state->compression_buffer)) != 0) 1090 goto out; 1091 DBG(debug("compression: raw %d compressed %zd", len, 1092 sshbuf_len(state->outgoing_packet))); 1093 } 1094 1095 /* sizeof (packet_len + pad_len + payload) */ 1096 len = sshbuf_len(state->outgoing_packet); 1097 1098 /* 1099 * calc size of padding, alloc space, get random data, 1100 * minimum padding is 4 bytes 1101 */ 1102 len -= aadlen; /* packet length is not encrypted for EtM modes */ 1103 padlen = block_size - (len % block_size); 1104 if (padlen < 4) 1105 padlen += block_size; 1106 if (state->extra_pad) { 1107 /* will wrap if extra_pad+padlen > 255 */ 1108 state->extra_pad = 1109 roundup(state->extra_pad, block_size); 1110 pad = state->extra_pad - 1111 ((len + padlen) % state->extra_pad); 1112 DBG(debug3("%s: adding %d (len %d padlen %d extra_pad %d)", 1113 __func__, pad, len, padlen, state->extra_pad)); 1114 padlen += pad; 1115 state->extra_pad = 0; 1116 } 1117 if ((r = sshbuf_reserve(state->outgoing_packet, padlen, &cp)) != 0) 1118 goto out; 1119 if (enc && !state->send_context.plaintext) { 1120 /* random padding */ 1121 arc4random_buf(cp, padlen); 1122 } else { 1123 /* clear padding */ 1124 explicit_bzero(cp, padlen); 1125 } 1126 /* sizeof (packet_len + pad_len + payload + padding) */ 1127 len = sshbuf_len(state->outgoing_packet); 1128 cp = sshbuf_mutable_ptr(state->outgoing_packet); 1129 if (cp == NULL) { 1130 r = SSH_ERR_INTERNAL_ERROR; 1131 goto out; 1132 } 1133 /* packet_length includes payload, padding and padding length field */ 1134 POKE_U32(cp, len - 4); 1135 cp[4] = padlen; 1136 DBG(debug("send: len %d (includes padlen %d, aadlen %d)", 1137 len, padlen, aadlen)); 1138 1139 /* compute MAC over seqnr and packet(length fields, payload, padding) */ 1140debug("mac %p, %d %d", mac, mac? mac->enabled : -1, mac ? mac->etm : -1); 1141 if (mac && mac->enabled && !mac->etm) { 1142 if ((r = mac_compute(mac, state->p_send.seqnr, 1143 sshbuf_ptr(state->outgoing_packet), len, 1144 macbuf, sizeof(macbuf))) != 0) 1145 goto out; 1146 DBG(debug("done calc MAC out #%d", state->p_send.seqnr)); 1147 } 1148 /* encrypt packet and append to output buffer. */ 1149 if ((r = sshbuf_reserve(state->output, 1150 sshbuf_len(state->outgoing_packet) + authlen, &cp)) != 0) 1151 goto out; 1152 if ((r = cipher_crypt(&state->send_context, state->p_send.seqnr, cp, 1153 sshbuf_ptr(state->outgoing_packet), 1154 len - aadlen, aadlen, authlen)) != 0) 1155 goto out; 1156 /* append unencrypted MAC */ 1157 if (mac && mac->enabled) { 1158 if (mac->etm) { 1159 /* EtM: compute mac over aadlen + cipher text */ 1160 if ((r = mac_compute(mac, state->p_send.seqnr, 1161 cp, len, macbuf, sizeof(macbuf))) != 0) 1162 goto out; 1163 DBG(debug("done calc MAC(EtM) out #%d", 1164 state->p_send.seqnr)); 1165 } 1166 if ((r = sshbuf_put(state->output, macbuf, mac->mac_len)) != 0) 1167 goto out; 1168 } 1169#ifdef PACKET_DEBUG 1170 fprintf(stderr, "encrypted: "); 1171 sshbuf_dump(state->output, stderr); 1172#endif 1173 /* increment sequence number for outgoing packets */ 1174 if (++state->p_send.seqnr == 0) 1175 logit("outgoing seqnr wraps around"); 1176 if (++state->p_send.packets == 0) 1177 if (!(ssh->compat & SSH_BUG_NOREKEY)) 1178 return SSH_ERR_NEED_REKEY; 1179 state->p_send.blocks += len / block_size; 1180 state->p_send.bytes += len; 1181 sshbuf_reset(state->outgoing_packet); 1182 1183 if (type == SSH2_MSG_NEWKEYS) 1184 r = ssh_set_newkeys(ssh, MODE_OUT); 1185 else if (type == SSH2_MSG_USERAUTH_SUCCESS && state->server_side) 1186 r = ssh_packet_enable_delayed_compress(ssh); 1187 else 1188 r = 0; 1189 out: 1190 if (r < 0) 1191 return r; 1192 else 1193 return len - 4; 1194} 1195 1196int 1197ssh_packet_send2(struct ssh *ssh) 1198{ 1199 struct session_state *state = ssh->state; 1200 struct packet *p; 1201 u_char type; 1202 int r; 1203 int packet_length; 1204 1205 type = sshbuf_ptr(state->outgoing_packet)[5]; 1206 1207 /* during rekeying we can only send key exchange messages */ 1208 if (state->rekeying) { 1209 if ((type < SSH2_MSG_TRANSPORT_MIN) || 1210 (type > SSH2_MSG_TRANSPORT_MAX) || 1211 (type == SSH2_MSG_SERVICE_REQUEST) || 1212 (type == SSH2_MSG_SERVICE_ACCEPT)) { 1213 debug("enqueue packet: %u", type); 1214 p = calloc(1, sizeof(*p)); 1215 if (p == NULL) 1216 return SSH_ERR_ALLOC_FAIL; 1217 p->type = type; 1218 p->payload = state->outgoing_packet; 1219 TAILQ_INSERT_TAIL(&state->outgoing, p, next); 1220 state->outgoing_packet = sshbuf_new(); 1221 if (state->outgoing_packet == NULL) 1222 return SSH_ERR_ALLOC_FAIL; 1223 return sshbuf_len(state->outgoing_packet); 1224 } 1225 } 1226 1227 /* rekeying starts with sending KEXINIT */ 1228 if (type == SSH2_MSG_KEXINIT) 1229 state->rekeying = 1; 1230 1231 if ((r = ssh_packet_send2_wrapped(ssh)) < 0) 1232 return r; 1233 1234 packet_length = r; 1235 1236 /* after a NEWKEYS message we can send the complete queue */ 1237 if (type == SSH2_MSG_NEWKEYS) { 1238 state->rekeying = 0; 1239 state->rekey_time = monotime(); 1240 while ((p = TAILQ_FIRST(&state->outgoing))) { 1241 type = p->type; 1242 debug("dequeue packet: %u", type); 1243 sshbuf_free(state->outgoing_packet); 1244 state->outgoing_packet = p->payload; 1245 TAILQ_REMOVE(&state->outgoing, p, next); 1246 free(p); 1247 if ((r = ssh_packet_send2_wrapped(ssh)) < 0) 1248 return r; 1249 packet_length += r; 1250 } 1251 } 1252 return packet_length; 1253} 1254 1255/* 1256 * Waits until a packet has been received, and returns its type. Note that 1257 * no other data is processed until this returns, so this function should not 1258 * be used during the interactive session. 1259 */ 1260 1261int 1262ssh_packet_read_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1263{ 1264 struct session_state *state = ssh->state; 1265 int len, r, ms_remain, cont; 1266 fd_set *setp; 1267 char buf[8192]; 1268 struct timeval timeout, start, *timeoutp = NULL; 1269 1270 DBG(debug("packet_read()")); 1271 1272 setp = (fd_set *)calloc(howmany(state->connection_in + 1, 1273 NFDBITS), sizeof(fd_mask)); 1274 if (setp == NULL) 1275 return SSH_ERR_ALLOC_FAIL; 1276 1277 /* 1278 * Since we are blocking, ensure that all written packets have 1279 * been sent. 1280 */ 1281 if ((r = ssh_packet_write_wait(ssh)) < 0) 1282 return r; 1283 1284 /* Stay in the loop until we have received a complete packet. */ 1285 for (;;) { 1286 /* Try to read a packet from the buffer. */ 1287 r = ssh_packet_read_poll_seqnr(ssh, typep, seqnr_p); 1288 if (r != 0) 1289 break; 1290 if (!compat20 && ( 1291 *typep == SSH_SMSG_SUCCESS 1292 || *typep == SSH_SMSG_FAILURE 1293 || *typep == SSH_CMSG_EOF 1294 || *typep == SSH_CMSG_EXIT_CONFIRMATION)) 1295 if ((r = sshpkt_get_end(ssh)) != 0) 1296 break; 1297 /* If we got a packet, return it. */ 1298 if (*typep != SSH_MSG_NONE) 1299 break; 1300 /* 1301 * Otherwise, wait for some data to arrive, add it to the 1302 * buffer, and try again. 1303 */ 1304 memset(setp, 0, howmany(state->connection_in + 1, 1305 NFDBITS) * sizeof(fd_mask)); 1306 FD_SET(state->connection_in, setp); 1307 1308 if (state->packet_timeout_ms > 0) { 1309 ms_remain = state->packet_timeout_ms; 1310 timeoutp = &timeout; 1311 } 1312 /* Wait for some data to arrive. */ 1313 for (;;) { 1314 if (state->packet_timeout_ms != -1) { 1315 ms_to_timeval(&timeout, ms_remain); 1316 gettimeofday(&start, NULL); 1317 } 1318 if ((r = select(state->connection_in + 1, setp, 1319 NULL, NULL, timeoutp)) >= 0) 1320 break; 1321 if (errno != EAGAIN && errno != EINTR) 1322 break; 1323 if (state->packet_timeout_ms == -1) 1324 continue; 1325 ms_subtract_diff(&start, &ms_remain); 1326 if (ms_remain <= 0) { 1327 r = 0; 1328 break; 1329 } 1330 } 1331 if (r == 0) 1332 return SSH_ERR_CONN_TIMEOUT; 1333 /* Read data from the socket. */ 1334 do { 1335 cont = 0; 1336 len = roaming_read(state->connection_in, buf, 1337 sizeof(buf), &cont); 1338 } while (len == 0 && cont); 1339 if (len == 0) 1340 return SSH_ERR_CONN_CLOSED; 1341 if (len < 0) 1342 return SSH_ERR_SYSTEM_ERROR; 1343 1344 /* Append it to the buffer. */ 1345 if ((r = ssh_packet_process_incoming(ssh, buf, len)) != 0) 1346 return r; 1347 } 1348 free(setp); 1349 return r; 1350} 1351 1352int 1353ssh_packet_read(struct ssh *ssh) 1354{ 1355 u_char type; 1356 int r; 1357 1358 if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0) 1359 fatal("%s: %s", __func__, ssh_err(r)); 1360 return type; 1361} 1362 1363/* 1364 * Waits until a packet has been received, verifies that its type matches 1365 * that given, and gives a fatal error and exits if there is a mismatch. 1366 */ 1367 1368int 1369ssh_packet_read_expect(struct ssh *ssh, u_int expected_type) 1370{ 1371 int r; 1372 u_char type; 1373 1374 if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0) 1375 return r; 1376 if (type != expected_type) { 1377 if ((r = sshpkt_disconnect(ssh, 1378 "Protocol error: expected packet type %d, got %d", 1379 expected_type, type)) != 0) 1380 return r; 1381 return SSH_ERR_PROTOCOL_ERROR; 1382 } 1383 return 0; 1384} 1385 1386/* Checks if a full packet is available in the data received so far via 1387 * packet_process_incoming. If so, reads the packet; otherwise returns 1388 * SSH_MSG_NONE. This does not wait for data from the connection. 1389 * 1390 * SSH_MSG_DISCONNECT is handled specially here. Also, 1391 * SSH_MSG_IGNORE messages are skipped by this function and are never returned 1392 * to higher levels. 1393 */ 1394 1395int 1396ssh_packet_read_poll1(struct ssh *ssh, u_char *typep) 1397{ 1398 struct session_state *state = ssh->state; 1399 u_int len, padded_len; 1400 const char *emsg; 1401 const u_char *cp; 1402 u_char *p; 1403 u_int checksum, stored_checksum; 1404 int r; 1405 1406 *typep = SSH_MSG_NONE; 1407 1408 /* Check if input size is less than minimum packet size. */ 1409 if (sshbuf_len(state->input) < 4 + 8) 1410 return 0; 1411 /* Get length of incoming packet. */ 1412 len = PEEK_U32(sshbuf_ptr(state->input)); 1413 if (len < 1 + 2 + 2 || len > 256 * 1024) { 1414 if ((r = sshpkt_disconnect(ssh, "Bad packet length %u", 1415 len)) != 0) 1416 return r; 1417 return SSH_ERR_CONN_CORRUPT; 1418 } 1419 padded_len = (len + 8) & ~7; 1420 1421 /* Check if the packet has been entirely received. */ 1422 if (sshbuf_len(state->input) < 4 + padded_len) 1423 return 0; 1424 1425 /* The entire packet is in buffer. */ 1426 1427 /* Consume packet length. */ 1428 if ((r = sshbuf_consume(state->input, 4)) != 0) 1429 goto out; 1430 1431 /* 1432 * Cryptographic attack detector for ssh 1433 * (C)1998 CORE-SDI, Buenos Aires Argentina 1434 * Ariel Futoransky(futo@core-sdi.com) 1435 */ 1436 if (!state->receive_context.plaintext) { 1437 emsg = NULL; 1438 switch (detect_attack(&state->deattack, 1439 sshbuf_ptr(state->input), padded_len)) { 1440 case DEATTACK_OK: 1441 break; 1442 case DEATTACK_DETECTED: 1443 emsg = "crc32 compensation attack detected"; 1444 break; 1445 case DEATTACK_DOS_DETECTED: 1446 emsg = "deattack denial of service detected"; 1447 break; 1448 default: 1449 emsg = "deattack error"; 1450 break; 1451 } 1452 if (emsg != NULL) { 1453 error("%s", emsg); 1454 if ((r = sshpkt_disconnect(ssh, "%s", emsg)) != 0 || 1455 (r = ssh_packet_write_wait(ssh)) != 0) 1456 return r; 1457 return SSH_ERR_CONN_CORRUPT; 1458 } 1459 } 1460 1461 /* Decrypt data to incoming_packet. */ 1462 sshbuf_reset(state->incoming_packet); 1463 if ((r = sshbuf_reserve(state->incoming_packet, padded_len, &p)) != 0) 1464 goto out; 1465 if ((r = cipher_crypt(&state->receive_context, 0, p, 1466 sshbuf_ptr(state->input), padded_len, 0, 0)) != 0) 1467 goto out; 1468 1469 if ((r = sshbuf_consume(state->input, padded_len)) != 0) 1470 goto out; 1471 1472#ifdef PACKET_DEBUG 1473 fprintf(stderr, "read_poll plain: "); 1474 sshbuf_dump(state->incoming_packet, stderr); 1475#endif 1476 1477 /* Compute packet checksum. */ 1478 checksum = ssh_crc32(sshbuf_ptr(state->incoming_packet), 1479 sshbuf_len(state->incoming_packet) - 4); 1480 1481 /* Skip padding. */ 1482 if ((r = sshbuf_consume(state->incoming_packet, 8 - len % 8)) != 0) 1483 goto out; 1484 1485 /* Test check bytes. */ 1486 if (len != sshbuf_len(state->incoming_packet)) { 1487 error("%s: len %d != sshbuf_len %zd", __func__, 1488 len, sshbuf_len(state->incoming_packet)); 1489 if ((r = sshpkt_disconnect(ssh, "invalid packet length")) != 0 || 1490 (r = ssh_packet_write_wait(ssh)) != 0) 1491 return r; 1492 return SSH_ERR_CONN_CORRUPT; 1493 } 1494 1495 cp = sshbuf_ptr(state->incoming_packet) + len - 4; 1496 stored_checksum = PEEK_U32(cp); 1497 if (checksum != stored_checksum) { 1498 error("Corrupted check bytes on input"); 1499 if ((r = sshpkt_disconnect(ssh, "connection corrupted")) != 0 || 1500 (r = ssh_packet_write_wait(ssh)) != 0) 1501 return r; 1502 return SSH_ERR_CONN_CORRUPT; 1503 } 1504 if ((r = sshbuf_consume_end(state->incoming_packet, 4)) < 0) 1505 goto out; 1506 1507 if (state->packet_compression) { 1508 sshbuf_reset(state->compression_buffer); 1509 if ((r = uncompress_buffer(ssh, state->incoming_packet, 1510 state->compression_buffer)) != 0) 1511 goto out; 1512 sshbuf_reset(state->incoming_packet); 1513 if ((r = sshbuf_putb(state->incoming_packet, 1514 state->compression_buffer)) != 0) 1515 goto out; 1516 } 1517 state->p_read.packets++; 1518 state->p_read.bytes += padded_len + 4; 1519 if ((r = sshbuf_get_u8(state->incoming_packet, typep)) != 0) 1520 goto out; 1521 if (*typep < SSH_MSG_MIN || *typep > SSH_MSG_MAX) { 1522 error("Invalid ssh1 packet type: %d", *typep); 1523 if ((r = sshpkt_disconnect(ssh, "invalid packet type")) != 0 || 1524 (r = ssh_packet_write_wait(ssh)) != 0) 1525 return r; 1526 return SSH_ERR_PROTOCOL_ERROR; 1527 } 1528 r = 0; 1529 out: 1530 return r; 1531} 1532 1533int 1534ssh_packet_read_poll2(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1535{ 1536 struct session_state *state = ssh->state; 1537 u_int padlen, need; 1538 u_char *cp, macbuf[SSH_DIGEST_MAX_LENGTH]; 1539 u_int maclen, aadlen = 0, authlen = 0, block_size; 1540 struct sshenc *enc = NULL; 1541 struct sshmac *mac = NULL; 1542 struct sshcomp *comp = NULL; 1543 int r; 1544 1545 *typep = SSH_MSG_NONE; 1546 1547 if (state->packet_discard) 1548 return 0; 1549 1550 if (state->newkeys[MODE_IN] != NULL) { 1551 enc = &state->newkeys[MODE_IN]->enc; 1552 mac = &state->newkeys[MODE_IN]->mac; 1553 comp = &state->newkeys[MODE_IN]->comp; 1554 /* disable mac for authenticated encryption */ 1555 if ((authlen = cipher_authlen(enc->cipher)) != 0) 1556 mac = NULL; 1557 } 1558 maclen = mac && mac->enabled ? mac->mac_len : 0; 1559 block_size = enc ? enc->block_size : 8; 1560 aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0; 1561 1562 if (aadlen && state->packlen == 0) { 1563 if (cipher_get_length(&state->receive_context, 1564 &state->packlen, state->p_read.seqnr, 1565 sshbuf_ptr(state->input), sshbuf_len(state->input)) != 0) 1566 return 0; 1567 if (state->packlen < 1 + 4 || 1568 state->packlen > PACKET_MAX_SIZE) { 1569#ifdef PACKET_DEBUG 1570 sshbuf_dump(state->input, stderr); 1571#endif 1572 logit("Bad packet length %u.", state->packlen); 1573 if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0) 1574 return r; 1575 } 1576 sshbuf_reset(state->incoming_packet); 1577 } else if (state->packlen == 0) { 1578 /* 1579 * check if input size is less than the cipher block size, 1580 * decrypt first block and extract length of incoming packet 1581 */ 1582 if (sshbuf_len(state->input) < block_size) 1583 return 0; 1584 sshbuf_reset(state->incoming_packet); 1585 if ((r = sshbuf_reserve(state->incoming_packet, block_size, 1586 &cp)) != 0) 1587 goto out; 1588 if ((r = cipher_crypt(&state->receive_context, 1589 state->p_send.seqnr, cp, sshbuf_ptr(state->input), 1590 block_size, 0, 0)) != 0) 1591 goto out; 1592 state->packlen = PEEK_U32(sshbuf_ptr(state->incoming_packet)); 1593 if (state->packlen < 1 + 4 || 1594 state->packlen > PACKET_MAX_SIZE) { 1595#ifdef PACKET_DEBUG 1596 fprintf(stderr, "input: \n"); 1597 sshbuf_dump(state->input, stderr); 1598 fprintf(stderr, "incoming_packet: \n"); 1599 sshbuf_dump(state->incoming_packet, stderr); 1600#endif 1601 logit("Bad packet length %u.", state->packlen); 1602 return ssh_packet_start_discard(ssh, enc, mac, 1603 state->packlen, PACKET_MAX_SIZE); 1604 } 1605 if ((r = sshbuf_consume(state->input, block_size)) != 0) 1606 goto out; 1607 } 1608 DBG(debug("input: packet len %u", state->packlen+4)); 1609 1610 if (aadlen) { 1611 /* only the payload is encrypted */ 1612 need = state->packlen; 1613 } else { 1614 /* 1615 * the payload size and the payload are encrypted, but we 1616 * have a partial packet of block_size bytes 1617 */ 1618 need = 4 + state->packlen - block_size; 1619 } 1620 DBG(debug("partial packet: block %d, need %d, maclen %d, authlen %d," 1621 " aadlen %d", block_size, need, maclen, authlen, aadlen)); 1622 if (need % block_size != 0) { 1623 logit("padding error: need %d block %d mod %d", 1624 need, block_size, need % block_size); 1625 return ssh_packet_start_discard(ssh, enc, mac, 1626 state->packlen, PACKET_MAX_SIZE - block_size); 1627 } 1628 /* 1629 * check if the entire packet has been received and 1630 * decrypt into incoming_packet: 1631 * 'aadlen' bytes are unencrypted, but authenticated. 1632 * 'need' bytes are encrypted, followed by either 1633 * 'authlen' bytes of authentication tag or 1634 * 'maclen' bytes of message authentication code. 1635 */ 1636 if (sshbuf_len(state->input) < aadlen + need + authlen + maclen) 1637 return 0; 1638#ifdef PACKET_DEBUG 1639 fprintf(stderr, "read_poll enc/full: "); 1640 sshbuf_dump(state->input, stderr); 1641#endif 1642 /* EtM: compute mac over encrypted input */ 1643 if (mac && mac->enabled && mac->etm) { 1644 if ((r = mac_compute(mac, state->p_read.seqnr, 1645 sshbuf_ptr(state->input), aadlen + need, 1646 macbuf, sizeof(macbuf))) != 0) 1647 goto out; 1648 } 1649 if ((r = sshbuf_reserve(state->incoming_packet, aadlen + need, 1650 &cp)) != 0) 1651 goto out; 1652 if ((r = cipher_crypt(&state->receive_context, state->p_read.seqnr, cp, 1653 sshbuf_ptr(state->input), need, aadlen, authlen)) != 0) 1654 goto out; 1655 if ((r = sshbuf_consume(state->input, aadlen + need + authlen)) != 0) 1656 goto out; 1657 /* 1658 * compute MAC over seqnr and packet, 1659 * increment sequence number for incoming packet 1660 */ 1661 if (mac && mac->enabled) { 1662 if (!mac->etm) 1663 if ((r = mac_compute(mac, state->p_read.seqnr, 1664 sshbuf_ptr(state->incoming_packet), 1665 sshbuf_len(state->incoming_packet), 1666 macbuf, sizeof(macbuf))) != 0) 1667 goto out; 1668 if (timingsafe_bcmp(macbuf, sshbuf_ptr(state->input), 1669 mac->mac_len) != 0) { 1670 logit("Corrupted MAC on input."); 1671 if (need > PACKET_MAX_SIZE) 1672 return SSH_ERR_INTERNAL_ERROR; 1673 return ssh_packet_start_discard(ssh, enc, mac, 1674 state->packlen, PACKET_MAX_SIZE - need); 1675 } 1676 1677 DBG(debug("MAC #%d ok", state->p_read.seqnr)); 1678 if ((r = sshbuf_consume(state->input, mac->mac_len)) != 0) 1679 goto out; 1680 } 1681 if (seqnr_p != NULL) 1682 *seqnr_p = state->p_read.seqnr; 1683 if (++state->p_read.seqnr == 0) 1684 logit("incoming seqnr wraps around"); 1685 if (++state->p_read.packets == 0) 1686 if (!(ssh->compat & SSH_BUG_NOREKEY)) 1687 return SSH_ERR_NEED_REKEY; 1688 state->p_read.blocks += (state->packlen + 4) / block_size; 1689 state->p_read.bytes += state->packlen + 4; 1690 1691 /* get padlen */ 1692 padlen = sshbuf_ptr(state->incoming_packet)[4]; 1693 DBG(debug("input: padlen %d", padlen)); 1694 if (padlen < 4) { 1695 if ((r = sshpkt_disconnect(ssh, 1696 "Corrupted padlen %d on input.", padlen)) != 0 || 1697 (r = ssh_packet_write_wait(ssh)) != 0) 1698 return r; 1699 return SSH_ERR_CONN_CORRUPT; 1700 } 1701 1702 /* skip packet size + padlen, discard padding */ 1703 if ((r = sshbuf_consume(state->incoming_packet, 4 + 1)) != 0 || 1704 ((r = sshbuf_consume_end(state->incoming_packet, padlen)) != 0)) 1705 goto out; 1706 1707 DBG(debug("input: len before de-compress %zd", 1708 sshbuf_len(state->incoming_packet))); 1709 if (comp && comp->enabled) { 1710 sshbuf_reset(state->compression_buffer); 1711 if ((r = uncompress_buffer(ssh, state->incoming_packet, 1712 state->compression_buffer)) != 0) 1713 goto out; 1714 sshbuf_reset(state->incoming_packet); 1715 if ((r = sshbuf_putb(state->incoming_packet, 1716 state->compression_buffer)) != 0) 1717 goto out; 1718 DBG(debug("input: len after de-compress %zd", 1719 sshbuf_len(state->incoming_packet))); 1720 } 1721 /* 1722 * get packet type, implies consume. 1723 * return length of payload (without type field) 1724 */ 1725 if ((r = sshbuf_get_u8(state->incoming_packet, typep)) != 0) 1726 goto out; 1727 if (*typep < SSH2_MSG_MIN || *typep >= SSH2_MSG_LOCAL_MIN) { 1728 if ((r = sshpkt_disconnect(ssh, 1729 "Invalid ssh2 packet type: %d", *typep)) != 0 || 1730 (r = ssh_packet_write_wait(ssh)) != 0) 1731 return r; 1732 return SSH_ERR_PROTOCOL_ERROR; 1733 } 1734 if (*typep == SSH2_MSG_NEWKEYS) 1735 r = ssh_set_newkeys(ssh, MODE_IN); 1736 else if (*typep == SSH2_MSG_USERAUTH_SUCCESS && !state->server_side) 1737 r = ssh_packet_enable_delayed_compress(ssh); 1738 else 1739 r = 0; 1740#ifdef PACKET_DEBUG 1741 fprintf(stderr, "read/plain[%d]:\r\n", *typep); 1742 sshbuf_dump(state->incoming_packet, stderr); 1743#endif 1744 /* reset for next packet */ 1745 state->packlen = 0; 1746 out: 1747 return r; 1748} 1749 1750int 1751ssh_packet_read_poll_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1752{ 1753 struct session_state *state = ssh->state; 1754 u_int reason, seqnr; 1755 int r; 1756 u_char *msg; 1757 1758 for (;;) { 1759 msg = NULL; 1760 if (compat20) { 1761 r = ssh_packet_read_poll2(ssh, typep, seqnr_p); 1762 if (r != 0) 1763 return r; 1764 if (*typep) { 1765 state->keep_alive_timeouts = 0; 1766 DBG(debug("received packet type %d", *typep)); 1767 } 1768 switch (*typep) { 1769 case SSH2_MSG_IGNORE: 1770 debug3("Received SSH2_MSG_IGNORE"); 1771 break; 1772 case SSH2_MSG_DEBUG: 1773 if ((r = sshpkt_get_u8(ssh, NULL)) != 0 || 1774 (r = sshpkt_get_string(ssh, &msg, NULL)) != 0 || 1775 (r = sshpkt_get_string(ssh, NULL, NULL)) != 0) { 1776 if (msg) 1777 free(msg); 1778 return r; 1779 } 1780 debug("Remote: %.900s", msg); 1781 free(msg); 1782 break; 1783 case SSH2_MSG_DISCONNECT: 1784 if ((r = sshpkt_get_u32(ssh, &reason)) != 0 || 1785 (r = sshpkt_get_string(ssh, &msg, NULL)) != 0) 1786 return r; 1787 /* Ignore normal client exit notifications */ 1788 do_log2(ssh->state->server_side && 1789 reason == SSH2_DISCONNECT_BY_APPLICATION ? 1790 SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_ERROR, 1791 "Received disconnect from %s: %u: %.400s", 1792 ssh_remote_ipaddr(ssh), reason, msg); 1793 free(msg); 1794 return SSH_ERR_DISCONNECTED; 1795 case SSH2_MSG_UNIMPLEMENTED: 1796 if ((r = sshpkt_get_u32(ssh, &seqnr)) != 0) 1797 return r; 1798 debug("Received SSH2_MSG_UNIMPLEMENTED for %u", 1799 seqnr); 1800 break; 1801 default: 1802 return 0; 1803 } 1804 } else { 1805 r = ssh_packet_read_poll1(ssh, typep); 1806 switch (*typep) { 1807 case SSH_MSG_NONE: 1808 return SSH_MSG_NONE; 1809 case SSH_MSG_IGNORE: 1810 break; 1811 case SSH_MSG_DEBUG: 1812 if ((r = sshpkt_get_string(ssh, &msg, NULL)) != 0) 1813 return r; 1814 debug("Remote: %.900s", msg); 1815 free(msg); 1816 break; 1817 case SSH_MSG_DISCONNECT: 1818 if ((r = sshpkt_get_string(ssh, &msg, NULL)) != 0) 1819 return r; 1820 error("Received disconnect from %s: %.400s", 1821 ssh_remote_ipaddr(ssh), msg); 1822 free(msg); 1823 return SSH_ERR_DISCONNECTED; 1824 default: 1825 DBG(debug("received packet type %d", *typep)); 1826 return 0; 1827 } 1828 } 1829 } 1830} 1831 1832/* 1833 * Buffers the given amount of input characters. This is intended to be used 1834 * together with packet_read_poll. 1835 */ 1836 1837int 1838ssh_packet_process_incoming(struct ssh *ssh, const char *buf, u_int len) 1839{ 1840 struct session_state *state = ssh->state; 1841 int r; 1842 1843 if (state->packet_discard) { 1844 state->keep_alive_timeouts = 0; /* ?? */ 1845 if (len >= state->packet_discard) { 1846 if ((r = ssh_packet_stop_discard(ssh)) != 0) 1847 return r; 1848 } 1849 state->packet_discard -= len; 1850 return 0; 1851 } 1852 if ((r = sshbuf_put(ssh->state->input, buf, len)) != 0) 1853 return r; 1854 1855 return 0; 1856} 1857 1858int 1859ssh_packet_remaining(struct ssh *ssh) 1860{ 1861 return sshbuf_len(ssh->state->incoming_packet); 1862} 1863 1864/* 1865 * Sends a diagnostic message from the server to the client. This message 1866 * can be sent at any time (but not while constructing another message). The 1867 * message is printed immediately, but only if the client is being executed 1868 * in verbose mode. These messages are primarily intended to ease debugging 1869 * authentication problems. The length of the formatted message must not 1870 * exceed 1024 bytes. This will automatically call ssh_packet_write_wait. 1871 */ 1872void 1873ssh_packet_send_debug(struct ssh *ssh, const char *fmt,...) 1874{ 1875 char buf[1024]; 1876 va_list args; 1877 int r; 1878 1879 if (compat20 && (ssh->compat & SSH_BUG_DEBUG)) 1880 return; 1881 1882 va_start(args, fmt); 1883 vsnprintf(buf, sizeof(buf), fmt, args); 1884 va_end(args); 1885 1886 if (compat20) { 1887 if ((r = sshpkt_start(ssh, SSH2_MSG_DEBUG)) != 0 || 1888 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* always display */ 1889 (r = sshpkt_put_cstring(ssh, buf)) != 0 || 1890 (r = sshpkt_put_cstring(ssh, "")) != 0 || 1891 (r = sshpkt_send(ssh)) != 0) 1892 fatal("%s: %s", __func__, ssh_err(r)); 1893 } else { 1894 if ((r = sshpkt_start(ssh, SSH_MSG_DEBUG)) != 0 || 1895 (r = sshpkt_put_cstring(ssh, buf)) != 0 || 1896 (r = sshpkt_send(ssh)) != 0) 1897 fatal("%s: %s", __func__, ssh_err(r)); 1898 } 1899 if ((r = ssh_packet_write_wait(ssh)) != 0) 1900 fatal("%s: %s", __func__, ssh_err(r)); 1901} 1902 1903/* 1904 * Pretty-print connection-terminating errors and exit. 1905 */ 1906void 1907sshpkt_fatal(struct ssh *ssh, const char *tag, int r) 1908{ 1909 switch (r) { 1910 case SSH_ERR_CONN_CLOSED: 1911 logit("Connection closed by %.200s", ssh_remote_ipaddr(ssh)); 1912 cleanup_exit(255); 1913 case SSH_ERR_CONN_TIMEOUT: 1914 logit("Connection to %.200s timed out while " 1915 "waiting to write", ssh_remote_ipaddr(ssh)); 1916 cleanup_exit(255); 1917 default: 1918 fatal("%s%sConnection to %.200s: %s", 1919 tag != NULL ? tag : "", tag != NULL ? ": " : "", 1920 ssh_remote_ipaddr(ssh), ssh_err(r)); 1921 } 1922} 1923 1924/* 1925 * Logs the error plus constructs and sends a disconnect packet, closes the 1926 * connection, and exits. This function never returns. The error message 1927 * should not contain a newline. The length of the formatted message must 1928 * not exceed 1024 bytes. 1929 */ 1930void 1931ssh_packet_disconnect(struct ssh *ssh, const char *fmt,...) 1932{ 1933 char buf[1024]; 1934 va_list args; 1935 static int disconnecting = 0; 1936 int r; 1937 1938 if (disconnecting) /* Guard against recursive invocations. */ 1939 fatal("packet_disconnect called recursively."); 1940 disconnecting = 1; 1941 1942 /* 1943 * Format the message. Note that the caller must make sure the 1944 * message is of limited size. 1945 */ 1946 va_start(args, fmt); 1947 vsnprintf(buf, sizeof(buf), fmt, args); 1948 va_end(args); 1949 1950 /* Display the error locally */ 1951 logit("Disconnecting: %.100s", buf); 1952 1953 /* 1954 * Send the disconnect message to the other side, and wait 1955 * for it to get sent. 1956 */ 1957 if ((r = sshpkt_disconnect(ssh, "%s", buf)) != 0) 1958 sshpkt_fatal(ssh, __func__, r); 1959 1960 if ((r = ssh_packet_write_wait(ssh)) != 0) 1961 sshpkt_fatal(ssh, __func__, r); 1962 1963 /* Close the connection. */ 1964 ssh_packet_close(ssh); 1965 cleanup_exit(255); 1966} 1967 1968/* 1969 * Checks if there is any buffered output, and tries to write some of 1970 * the output. 1971 */ 1972int 1973ssh_packet_write_poll(struct ssh *ssh) 1974{ 1975 struct session_state *state = ssh->state; 1976 int len = sshbuf_len(state->output); 1977 int cont, r; 1978 1979 if (len > 0) { 1980 cont = 0; 1981 len = roaming_write(state->connection_out, 1982 sshbuf_ptr(state->output), len, &cont); 1983 if (len == -1) { 1984 if (errno == EINTR || errno == EAGAIN) 1985 return 0; 1986 return SSH_ERR_SYSTEM_ERROR; 1987 } 1988 if (len == 0 && !cont) 1989 return SSH_ERR_CONN_CLOSED; 1990 if ((r = sshbuf_consume(state->output, len)) < 0) 1991 return r; 1992 } 1993 return len; 1994} 1995 1996/* 1997 * Calls packet_write_poll repeatedly until all pending output data has been 1998 * written. 1999 */ 2000int 2001ssh_packet_write_wait(struct ssh *ssh) 2002{ 2003 fd_set *setp; 2004 int ret, r, ms_remain = 0; 2005 struct timeval start, timeout, *timeoutp = NULL; 2006 u_int bytes_sent = 0; 2007 struct session_state *state = ssh->state; 2008 2009 setp = calloc(howmany(state->connection_out + 1, 2010 NFDBITS), sizeof(fd_mask)); 2011 if (setp == NULL) 2012 return SSH_ERR_ALLOC_FAIL; 2013 bytes_sent += ssh_packet_write_poll(ssh); 2014 while (ssh_packet_have_data_to_write(ssh)) { 2015 memset(setp, 0, howmany(state->connection_out + 1, 2016 NFDBITS) * sizeof(fd_mask)); 2017 FD_SET(state->connection_out, setp); 2018 2019 if (state->packet_timeout_ms > 0) { 2020 ms_remain = state->packet_timeout_ms; 2021 timeoutp = &timeout; 2022 } 2023 for (;;) { 2024 if (state->packet_timeout_ms != -1) { 2025 ms_to_timeval(&timeout, ms_remain); 2026 gettimeofday(&start, NULL); 2027 } 2028 if ((ret = select(state->connection_out + 1, 2029 NULL, setp, NULL, timeoutp)) >= 0) 2030 break; 2031 if (errno != EAGAIN && errno != EINTR) 2032 break; 2033 if (state->packet_timeout_ms == -1) 2034 continue; 2035 ms_subtract_diff(&start, &ms_remain); 2036 if (ms_remain <= 0) { 2037 ret = 0; 2038 break; 2039 } 2040 } 2041 if (ret == 0) { 2042 free(setp); 2043 return SSH_ERR_CONN_TIMEOUT; 2044 } 2045 if ((r = ssh_packet_write_poll(ssh)) < 0) { 2046 free(setp); 2047 return r; 2048 } 2049 bytes_sent += r; 2050 } 2051 free(setp); 2052 return bytes_sent; 2053} 2054 2055/* Returns true if there is buffered data to write to the connection. */ 2056 2057int 2058ssh_packet_have_data_to_write(struct ssh *ssh) 2059{ 2060 return sshbuf_len(ssh->state->output) != 0; 2061} 2062 2063/* Returns true if there is not too much data to write to the connection. */ 2064 2065int 2066ssh_packet_not_very_much_data_to_write(struct ssh *ssh) 2067{ 2068 if (ssh->state->interactive_mode) 2069 return sshbuf_len(ssh->state->output) < 16384; 2070 else 2071 return sshbuf_len(ssh->state->output) < 128 * 1024; 2072} 2073 2074void 2075ssh_packet_set_tos(struct ssh *ssh, int tos) 2076{ 2077 if (!ssh_packet_connection_is_on_socket(ssh)) 2078 return; 2079 switch (ssh_packet_connection_af(ssh)) { 2080 case AF_INET: 2081 debug3("%s: set IP_TOS 0x%02x", __func__, tos); 2082 if (setsockopt(ssh->state->connection_in, 2083 IPPROTO_IP, IP_TOS, &tos, sizeof(tos)) < 0) 2084 error("setsockopt IP_TOS %d: %.100s:", 2085 tos, strerror(errno)); 2086 break; 2087 case AF_INET6: 2088 debug3("%s: set IPV6_TCLASS 0x%02x", __func__, tos); 2089 if (setsockopt(ssh->state->connection_in, 2090 IPPROTO_IPV6, IPV6_TCLASS, &tos, sizeof(tos)) < 0) 2091 error("setsockopt IPV6_TCLASS %d: %.100s:", 2092 tos, strerror(errno)); 2093 break; 2094 } 2095} 2096 2097/* Informs that the current session is interactive. Sets IP flags for that. */ 2098 2099void 2100ssh_packet_set_interactive(struct ssh *ssh, int interactive, int qos_interactive, int qos_bulk) 2101{ 2102 struct session_state *state = ssh->state; 2103 2104 if (state->set_interactive_called) 2105 return; 2106 state->set_interactive_called = 1; 2107 2108 /* Record that we are in interactive mode. */ 2109 state->interactive_mode = interactive; 2110 2111 /* Only set socket options if using a socket. */ 2112 if (!ssh_packet_connection_is_on_socket(ssh)) 2113 return; 2114 set_nodelay(state->connection_in); 2115 ssh_packet_set_tos(ssh, interactive ? qos_interactive : 2116 qos_bulk); 2117} 2118 2119/* Returns true if the current connection is interactive. */ 2120 2121int 2122ssh_packet_is_interactive(struct ssh *ssh) 2123{ 2124 return ssh->state->interactive_mode; 2125} 2126 2127int 2128ssh_packet_set_maxsize(struct ssh *ssh, u_int s) 2129{ 2130 struct session_state *state = ssh->state; 2131 2132 if (state->set_maxsize_called) { 2133 logit("packet_set_maxsize: called twice: old %d new %d", 2134 state->max_packet_size, s); 2135 return -1; 2136 } 2137 if (s < 4 * 1024 || s > 1024 * 1024) { 2138 logit("packet_set_maxsize: bad size %d", s); 2139 return -1; 2140 } 2141 state->set_maxsize_called = 1; 2142 debug("packet_set_maxsize: setting to %d", s); 2143 state->max_packet_size = s; 2144 return s; 2145} 2146 2147int 2148ssh_packet_inc_alive_timeouts(struct ssh *ssh) 2149{ 2150 return ++ssh->state->keep_alive_timeouts; 2151} 2152 2153void 2154ssh_packet_set_alive_timeouts(struct ssh *ssh, int ka) 2155{ 2156 ssh->state->keep_alive_timeouts = ka; 2157} 2158 2159u_int 2160ssh_packet_get_maxsize(struct ssh *ssh) 2161{ 2162 return ssh->state->max_packet_size; 2163} 2164 2165/* 2166 * 9.2. Ignored Data Message 2167 * 2168 * byte SSH_MSG_IGNORE 2169 * string data 2170 * 2171 * All implementations MUST understand (and ignore) this message at any 2172 * time (after receiving the protocol version). No implementation is 2173 * required to send them. This message can be used as an additional 2174 * protection measure against advanced traffic analysis techniques. 2175 */ 2176void 2177ssh_packet_send_ignore(struct ssh *ssh, int nbytes) 2178{ 2179 u_int32_t rnd = 0; 2180 int r, i; 2181 2182 if ((r = sshpkt_start(ssh, compat20 ? 2183 SSH2_MSG_IGNORE : SSH_MSG_IGNORE)) != 0 || 2184 (r = sshpkt_put_u32(ssh, nbytes)) != 0) 2185 fatal("%s: %s", __func__, ssh_err(r)); 2186 for (i = 0; i < nbytes; i++) { 2187 if (i % 4 == 0) 2188 rnd = arc4random(); 2189 if ((r = sshpkt_put_u8(ssh, (u_char)rnd & 0xff)) != 0) 2190 fatal("%s: %s", __func__, ssh_err(r)); 2191 rnd >>= 8; 2192 } 2193} 2194 2195int rekey_requested = 0; 2196void 2197ssh_packet_request_rekeying(void) 2198{ 2199 rekey_requested = 1; 2200} 2201 2202#define MAX_PACKETS (1U<<31) 2203int 2204ssh_packet_need_rekeying(struct ssh *ssh) 2205{ 2206 struct session_state *state = ssh->state; 2207 2208 if (ssh->compat & SSH_BUG_NOREKEY) 2209 return 0; 2210 if (rekey_requested == 1) 2211 { 2212 rekey_requested = 0; 2213 return 1; 2214 } 2215 return 2216 (state->p_send.packets > MAX_PACKETS) || 2217 (state->p_read.packets > MAX_PACKETS) || 2218 (state->max_blocks_out && 2219 (state->p_send.blocks > state->max_blocks_out)) || 2220 (state->max_blocks_in && 2221 (state->p_read.blocks > state->max_blocks_in)) || 2222 (state->rekey_interval != 0 && state->rekey_time + 2223 state->rekey_interval <= monotime()); 2224} 2225 2226void 2227ssh_packet_set_rekey_limits(struct ssh *ssh, u_int32_t bytes, time_t seconds) 2228{ 2229 debug3("rekey after %lld bytes, %d seconds", (long long)bytes, 2230 (int)seconds); 2231 ssh->state->rekey_limit = bytes; 2232 ssh->state->rekey_interval = seconds; 2233} 2234 2235time_t 2236ssh_packet_get_rekey_timeout(struct ssh *ssh) 2237{ 2238 time_t seconds; 2239 2240 seconds = ssh->state->rekey_time + ssh->state->rekey_interval - 2241 monotime(); 2242 return (seconds <= 0 ? 1 : seconds); 2243} 2244 2245void 2246ssh_packet_set_server(struct ssh *ssh) 2247{ 2248 ssh->state->server_side = 1; 2249} 2250 2251void 2252ssh_packet_set_authenticated(struct ssh *ssh) 2253{ 2254 ssh->state->after_authentication = 1; 2255} 2256 2257void * 2258ssh_packet_get_input(struct ssh *ssh) 2259{ 2260 return (void *)ssh->state->input; 2261} 2262 2263void * 2264ssh_packet_get_output(struct ssh *ssh) 2265{ 2266 return (void *)ssh->state->output; 2267} 2268 2269/* XXX TODO update roaming to new API (does not work anyway) */ 2270/* 2271 * Save the state for the real connection, and use a separate state when 2272 * resuming a suspended connection. 2273 */ 2274void 2275ssh_packet_backup_state(struct ssh *ssh, 2276 struct ssh *backup_state) 2277{ 2278 struct ssh *tmp; 2279 2280 close(ssh->state->connection_in); 2281 ssh->state->connection_in = -1; 2282 close(ssh->state->connection_out); 2283 ssh->state->connection_out = -1; 2284 if (backup_state) 2285 tmp = backup_state; 2286 else 2287 tmp = ssh_alloc_session_state(); 2288 backup_state = ssh; 2289 ssh = tmp; 2290} 2291 2292/* XXX FIXME FIXME FIXME */ 2293/* 2294 * Swap in the old state when resuming a connecion. 2295 */ 2296void 2297ssh_packet_restore_state(struct ssh *ssh, 2298 struct ssh *backup_state) 2299{ 2300 struct ssh *tmp; 2301 u_int len; 2302 int r; 2303 2304 tmp = backup_state; 2305 backup_state = ssh; 2306 ssh = tmp; 2307 ssh->state->connection_in = backup_state->state->connection_in; 2308 backup_state->state->connection_in = -1; 2309 ssh->state->connection_out = backup_state->state->connection_out; 2310 backup_state->state->connection_out = -1; 2311 len = sshbuf_len(backup_state->state->input); 2312 if (len > 0) { 2313 if ((r = sshbuf_putb(ssh->state->input, 2314 backup_state->state->input)) != 0) 2315 fatal("%s: %s", __func__, ssh_err(r)); 2316 sshbuf_reset(backup_state->state->input); 2317 add_recv_bytes(len); 2318 } 2319} 2320 2321/* Reset after_authentication and reset compression in post-auth privsep */ 2322static int 2323ssh_packet_set_postauth(struct ssh *ssh) 2324{ 2325 struct sshcomp *comp; 2326 int r, mode; 2327 2328 debug("%s: called", __func__); 2329 /* This was set in net child, but is not visible in user child */ 2330 ssh->state->after_authentication = 1; 2331 ssh->state->rekeying = 0; 2332 for (mode = 0; mode < MODE_MAX; mode++) { 2333 if (ssh->state->newkeys[mode] == NULL) 2334 continue; 2335 comp = &ssh->state->newkeys[mode]->comp; 2336 if (comp && comp->enabled && 2337 (r = ssh_packet_init_compression(ssh)) != 0) 2338 return r; 2339 } 2340 return 0; 2341} 2342 2343/* Packet state (de-)serialization for privsep */ 2344 2345/* turn kex into a blob for packet state serialization */ 2346static int 2347kex_to_blob(struct sshbuf *m, struct kex *kex) 2348{ 2349 int r; 2350 2351 if ((r = sshbuf_put_string(m, kex->session_id, 2352 kex->session_id_len)) != 0 || 2353 (r = sshbuf_put_u32(m, kex->we_need)) != 0 || 2354 (r = sshbuf_put_u32(m, kex->hostkey_type)) != 0 || 2355 (r = sshbuf_put_u32(m, kex->kex_type)) != 0 || 2356 (r = sshbuf_put_stringb(m, kex->my)) != 0 || 2357 (r = sshbuf_put_stringb(m, kex->peer)) != 0 || 2358 (r = sshbuf_put_u32(m, kex->flags)) != 0 || 2359 (r = sshbuf_put_cstring(m, kex->client_version_string)) != 0 || 2360 (r = sshbuf_put_cstring(m, kex->server_version_string)) != 0) 2361 return r; 2362 return 0; 2363} 2364 2365/* turn key exchange results into a blob for packet state serialization */ 2366static int 2367newkeys_to_blob(struct sshbuf *m, struct ssh *ssh, int mode) 2368{ 2369 struct sshbuf *b; 2370 struct sshcipher_ctx *cc; 2371 struct sshcomp *comp; 2372 struct sshenc *enc; 2373 struct sshmac *mac; 2374 struct newkeys *newkey; 2375 int r; 2376 2377 if ((newkey = ssh->state->newkeys[mode]) == NULL) 2378 return SSH_ERR_INTERNAL_ERROR; 2379 enc = &newkey->enc; 2380 mac = &newkey->mac; 2381 comp = &newkey->comp; 2382 cc = (mode == MODE_OUT) ? &ssh->state->send_context : 2383 &ssh->state->receive_context; 2384 if ((r = cipher_get_keyiv(cc, enc->iv, enc->iv_len)) != 0) 2385 return r; 2386 if ((b = sshbuf_new()) == NULL) 2387 return SSH_ERR_ALLOC_FAIL; 2388 /* The cipher struct is constant and shared, you export pointer */ 2389 if ((r = sshbuf_put_cstring(b, enc->name)) != 0 || 2390 (r = sshbuf_put(b, &enc->cipher, sizeof(enc->cipher))) != 0 || 2391 (r = sshbuf_put_u32(b, enc->enabled)) != 0 || 2392 (r = sshbuf_put_u32(b, enc->block_size)) != 0 || 2393 (r = sshbuf_put_string(b, enc->key, enc->key_len)) != 0 || 2394 (r = sshbuf_put_string(b, enc->iv, enc->iv_len)) != 0) 2395 goto out; 2396 if (cipher_authlen(enc->cipher) == 0) { 2397 if ((r = sshbuf_put_cstring(b, mac->name)) != 0 || 2398 (r = sshbuf_put_u32(b, mac->enabled)) != 0 || 2399 (r = sshbuf_put_string(b, mac->key, mac->key_len)) != 0) 2400 goto out; 2401 } 2402 if ((r = sshbuf_put_u32(b, comp->type)) != 0 || 2403 (r = sshbuf_put_u32(b, comp->enabled)) != 0 || 2404 (r = sshbuf_put_cstring(b, comp->name)) != 0) 2405 goto out; 2406 r = sshbuf_put_stringb(m, b); 2407 out: 2408 if (b != NULL) 2409 sshbuf_free(b); 2410 return r; 2411} 2412 2413/* serialize packet state into a blob */ 2414int 2415ssh_packet_get_state(struct ssh *ssh, struct sshbuf *m) 2416{ 2417 struct session_state *state = ssh->state; 2418 u_char *p; 2419 size_t slen, rlen; 2420 int r, ssh1cipher; 2421 2422 if (!compat20) { 2423 ssh1cipher = cipher_get_number(state->receive_context.cipher); 2424 slen = cipher_get_keyiv_len(&state->send_context); 2425 rlen = cipher_get_keyiv_len(&state->receive_context); 2426 if ((r = sshbuf_put_u32(m, state->remote_protocol_flags)) != 0 || 2427 (r = sshbuf_put_u32(m, ssh1cipher)) != 0 || 2428 (r = sshbuf_put_string(m, state->ssh1_key, state->ssh1_keylen)) != 0 || 2429 (r = sshbuf_put_u32(m, slen)) != 0 || 2430 (r = sshbuf_reserve(m, slen, &p)) != 0 || 2431 (r = cipher_get_keyiv(&state->send_context, p, slen)) != 0 || 2432 (r = sshbuf_put_u32(m, rlen)) != 0 || 2433 (r = sshbuf_reserve(m, rlen, &p)) != 0 || 2434 (r = cipher_get_keyiv(&state->receive_context, p, rlen)) != 0) 2435 return r; 2436 } else { 2437 if ((r = kex_to_blob(m, ssh->kex)) != 0 || 2438 (r = newkeys_to_blob(m, ssh, MODE_OUT)) != 0 || 2439 (r = newkeys_to_blob(m, ssh, MODE_IN)) != 0 || 2440 (r = sshbuf_put_u32(m, state->rekey_limit)) != 0 || 2441 (r = sshbuf_put_u32(m, state->rekey_interval)) != 0 || 2442 (r = sshbuf_put_u32(m, state->p_send.seqnr)) != 0 || 2443 (r = sshbuf_put_u64(m, state->p_send.blocks)) != 0 || 2444 (r = sshbuf_put_u32(m, state->p_send.packets)) != 0 || 2445 (r = sshbuf_put_u64(m, state->p_send.bytes)) != 0 || 2446 (r = sshbuf_put_u32(m, state->p_read.seqnr)) != 0 || 2447 (r = sshbuf_put_u64(m, state->p_read.blocks)) != 0 || 2448 (r = sshbuf_put_u32(m, state->p_read.packets)) != 0 || 2449 (r = sshbuf_put_u64(m, state->p_read.bytes)) != 0) 2450 return r; 2451 } 2452 2453 slen = cipher_get_keycontext(&state->send_context, NULL); 2454 rlen = cipher_get_keycontext(&state->receive_context, NULL); 2455 if ((r = sshbuf_put_u32(m, slen)) != 0 || 2456 (r = sshbuf_reserve(m, slen, &p)) != 0) 2457 return r; 2458 if (cipher_get_keycontext(&state->send_context, p) != (int)slen) 2459 return SSH_ERR_INTERNAL_ERROR; 2460 if ((r = sshbuf_put_u32(m, rlen)) != 0 || 2461 (r = sshbuf_reserve(m, rlen, &p)) != 0) 2462 return r; 2463 if (cipher_get_keycontext(&state->receive_context, p) != (int)rlen) 2464 return SSH_ERR_INTERNAL_ERROR; 2465 2466 if ((r = ssh_packet_get_compress_state(m, ssh)) != 0 || 2467 (r = sshbuf_put_stringb(m, state->input)) != 0 || 2468 (r = sshbuf_put_stringb(m, state->output)) != 0) 2469 return r; 2470 2471 if (compat20) { 2472 if ((r = sshbuf_put_u64(m, get_sent_bytes())) != 0 || 2473 (r = sshbuf_put_u64(m, get_recv_bytes())) != 0) 2474 return r; 2475 } 2476 return 0; 2477} 2478 2479/* restore key exchange results from blob for packet state de-serialization */ 2480static int 2481newkeys_from_blob(struct sshbuf *m, struct ssh *ssh, int mode) 2482{ 2483 struct sshbuf *b = NULL; 2484 struct sshcomp *comp; 2485 struct sshenc *enc; 2486 struct sshmac *mac; 2487 struct newkeys *newkey = NULL; 2488 size_t keylen, ivlen, maclen; 2489 int r; 2490 2491 if ((newkey = calloc(1, sizeof(*newkey))) == NULL) { 2492 r = SSH_ERR_ALLOC_FAIL; 2493 goto out; 2494 } 2495 if ((r = sshbuf_froms(m, &b)) != 0) 2496 goto out; 2497#ifdef DEBUG_PK 2498 sshbuf_dump(b, stderr); 2499#endif 2500 enc = &newkey->enc; 2501 mac = &newkey->mac; 2502 comp = &newkey->comp; 2503 2504 if ((r = sshbuf_get_cstring(b, &enc->name, NULL)) != 0 || 2505 (r = sshbuf_get(b, &enc->cipher, sizeof(enc->cipher))) != 0 || 2506 (r = sshbuf_get_u32(b, (u_int *)&enc->enabled)) != 0 || 2507 (r = sshbuf_get_u32(b, &enc->block_size)) != 0 || 2508 (r = sshbuf_get_string(b, &enc->key, &keylen)) != 0 || 2509 (r = sshbuf_get_string(b, &enc->iv, &ivlen)) != 0) 2510 goto out; 2511 if (cipher_authlen(enc->cipher) == 0) { 2512 if ((r = sshbuf_get_cstring(b, &mac->name, NULL)) != 0) 2513 goto out; 2514 if ((r = mac_setup(mac, mac->name)) != 0) 2515 goto out; 2516 if ((r = sshbuf_get_u32(b, (u_int *)&mac->enabled)) != 0 || 2517 (r = sshbuf_get_string(b, &mac->key, &maclen)) != 0) 2518 goto out; 2519 if (maclen > mac->key_len) { 2520 r = SSH_ERR_INVALID_FORMAT; 2521 goto out; 2522 } 2523 mac->key_len = maclen; 2524 } 2525 if ((r = sshbuf_get_u32(b, &comp->type)) != 0 || 2526 (r = sshbuf_get_u32(b, (u_int *)&comp->enabled)) != 0 || 2527 (r = sshbuf_get_cstring(b, &comp->name, NULL)) != 0) 2528 goto out; 2529 if (enc->name == NULL || 2530 cipher_by_name(enc->name) != enc->cipher) { 2531 r = SSH_ERR_INVALID_FORMAT; 2532 goto out; 2533 } 2534 if (sshbuf_len(b) != 0) { 2535 r = SSH_ERR_INVALID_FORMAT; 2536 goto out; 2537 } 2538 enc->key_len = keylen; 2539 enc->iv_len = ivlen; 2540 ssh->kex->newkeys[mode] = newkey; 2541 newkey = NULL; 2542 r = 0; 2543 out: 2544 if (newkey != NULL) 2545 free(newkey); 2546 if (b != NULL) 2547 sshbuf_free(b); 2548 return r; 2549} 2550 2551/* restore kex from blob for packet state de-serialization */ 2552static int 2553kex_from_blob(struct sshbuf *m, struct kex **kexp) 2554{ 2555 struct kex *kex; 2556 int r; 2557 2558 if ((kex = calloc(1, sizeof(struct kex))) == NULL || 2559 (kex->my = sshbuf_new()) == NULL || 2560 (kex->peer = sshbuf_new()) == NULL) { 2561 r = SSH_ERR_ALLOC_FAIL; 2562 goto out; 2563 } 2564 if ((r = sshbuf_get_string(m, &kex->session_id, &kex->session_id_len)) != 0 || 2565 (r = sshbuf_get_u32(m, &kex->we_need)) != 0 || 2566 (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_type)) != 0 || 2567 (r = sshbuf_get_u32(m, &kex->kex_type)) != 0 || 2568 (r = sshbuf_get_stringb(m, kex->my)) != 0 || 2569 (r = sshbuf_get_stringb(m, kex->peer)) != 0 || 2570 (r = sshbuf_get_u32(m, &kex->flags)) != 0 || 2571 (r = sshbuf_get_cstring(m, &kex->client_version_string, NULL)) != 0 || 2572 (r = sshbuf_get_cstring(m, &kex->server_version_string, NULL)) != 0) 2573 goto out; 2574 kex->server = 1; 2575 kex->done = 1; 2576 r = 0; 2577 out: 2578 if (r != 0 || kexp == NULL) { 2579 if (kex != NULL) { 2580 if (kex->my != NULL) 2581 sshbuf_free(kex->my); 2582 if (kex->peer != NULL) 2583 sshbuf_free(kex->peer); 2584 free(kex); 2585 } 2586 if (kexp != NULL) 2587 *kexp = NULL; 2588 } else { 2589 *kexp = kex; 2590 } 2591 return r; 2592} 2593 2594/* 2595 * Restore packet state from content of blob 'm' (de-serialization). 2596 * Note that 'm' will be partially consumed on parsing or any other errors. 2597 */ 2598int 2599ssh_packet_set_state(struct ssh *ssh, struct sshbuf *m) 2600{ 2601 struct session_state *state = ssh->state; 2602 const u_char *ssh1key, *ivin, *ivout, *keyin, *keyout, *input, *output; 2603 size_t ssh1keylen, rlen, slen, ilen, olen; 2604 int r; 2605 u_int ssh1cipher = 0; 2606 u_int64_t sent_bytes = 0, recv_bytes = 0; 2607 2608 if (!compat20) { 2609 if ((r = sshbuf_get_u32(m, &state->remote_protocol_flags)) != 0 || 2610 (r = sshbuf_get_u32(m, &ssh1cipher)) != 0 || 2611 (r = sshbuf_get_string_direct(m, &ssh1key, &ssh1keylen)) != 0 || 2612 (r = sshbuf_get_string_direct(m, &ivout, &slen)) != 0 || 2613 (r = sshbuf_get_string_direct(m, &ivin, &rlen)) != 0) 2614 return r; 2615 if (ssh1cipher > INT_MAX) 2616 return SSH_ERR_KEY_UNKNOWN_CIPHER; 2617 ssh_packet_set_encryption_key(ssh, ssh1key, ssh1keylen, 2618 (int)ssh1cipher); 2619 if (cipher_get_keyiv_len(&state->send_context) != (int)slen || 2620 cipher_get_keyiv_len(&state->receive_context) != (int)rlen) 2621 return SSH_ERR_INVALID_FORMAT; 2622 if ((r = cipher_set_keyiv(&state->send_context, ivout)) != 0 || 2623 (r = cipher_set_keyiv(&state->receive_context, ivin)) != 0) 2624 return r; 2625 } else { 2626 if ((r = kex_from_blob(m, &ssh->kex)) != 0 || 2627 (r = newkeys_from_blob(m, ssh, MODE_OUT)) != 0 || 2628 (r = newkeys_from_blob(m, ssh, MODE_IN)) != 0 || 2629 (r = sshbuf_get_u32(m, &state->rekey_limit)) != 0 || 2630 (r = sshbuf_get_u32(m, &state->rekey_interval)) != 0 || 2631 (r = sshbuf_get_u32(m, &state->p_send.seqnr)) != 0 || 2632 (r = sshbuf_get_u64(m, &state->p_send.blocks)) != 0 || 2633 (r = sshbuf_get_u32(m, &state->p_send.packets)) != 0 || 2634 (r = sshbuf_get_u64(m, &state->p_send.bytes)) != 0 || 2635 (r = sshbuf_get_u32(m, &state->p_read.seqnr)) != 0 || 2636 (r = sshbuf_get_u64(m, &state->p_read.blocks)) != 0 || 2637 (r = sshbuf_get_u32(m, &state->p_read.packets)) != 0 || 2638 (r = sshbuf_get_u64(m, &state->p_read.bytes)) != 0) 2639 return r; 2640 /* 2641 * We set the time here so that in post-auth privsep slave we 2642 * count from the completion of the authentication. 2643 */ 2644 state->rekey_time = monotime(); 2645 /* XXX ssh_set_newkeys overrides p_read.packets? XXX */ 2646 if ((r = ssh_set_newkeys(ssh, MODE_IN)) != 0 || 2647 (r = ssh_set_newkeys(ssh, MODE_OUT)) != 0) 2648 return r; 2649 } 2650 if ((r = sshbuf_get_string_direct(m, &keyout, &slen)) != 0 || 2651 (r = sshbuf_get_string_direct(m, &keyin, &rlen)) != 0) 2652 return r; 2653 if (cipher_get_keycontext(&state->send_context, NULL) != (int)slen || 2654 cipher_get_keycontext(&state->receive_context, NULL) != (int)rlen) 2655 return SSH_ERR_INVALID_FORMAT; 2656 cipher_set_keycontext(&state->send_context, keyout); 2657 cipher_set_keycontext(&state->receive_context, keyin); 2658 2659 if ((r = ssh_packet_set_compress_state(ssh, m)) != 0 || 2660 (r = ssh_packet_set_postauth(ssh)) != 0) 2661 return r; 2662 2663 sshbuf_reset(state->input); 2664 sshbuf_reset(state->output); 2665 if ((r = sshbuf_get_string_direct(m, &input, &ilen)) != 0 || 2666 (r = sshbuf_get_string_direct(m, &output, &olen)) != 0 || 2667 (r = sshbuf_put(state->input, input, ilen)) != 0 || 2668 (r = sshbuf_put(state->output, output, olen)) != 0) 2669 return r; 2670 2671 if (compat20) { 2672 if ((r = sshbuf_get_u64(m, &sent_bytes)) != 0 || 2673 (r = sshbuf_get_u64(m, &recv_bytes)) != 0) 2674 return r; 2675 roam_set_bytes(sent_bytes, recv_bytes); 2676 } 2677 if (sshbuf_len(m)) 2678 return SSH_ERR_INVALID_FORMAT; 2679 debug3("%s: done", __func__); 2680 return 0; 2681} 2682 2683/* NEW API */ 2684 2685/* put data to the outgoing packet */ 2686 2687int 2688sshpkt_put(struct ssh *ssh, const void *v, size_t len) 2689{ 2690 return sshbuf_put(ssh->state->outgoing_packet, v, len); 2691} 2692 2693int 2694sshpkt_putb(struct ssh *ssh, const struct sshbuf *b) 2695{ 2696 return sshbuf_putb(ssh->state->outgoing_packet, b); 2697} 2698 2699int 2700sshpkt_put_u8(struct ssh *ssh, u_char val) 2701{ 2702 return sshbuf_put_u8(ssh->state->outgoing_packet, val); 2703} 2704 2705int 2706sshpkt_put_u32(struct ssh *ssh, u_int32_t val) 2707{ 2708 return sshbuf_put_u32(ssh->state->outgoing_packet, val); 2709} 2710 2711int 2712sshpkt_put_u64(struct ssh *ssh, u_int64_t val) 2713{ 2714 return sshbuf_put_u64(ssh->state->outgoing_packet, val); 2715} 2716 2717int 2718sshpkt_put_string(struct ssh *ssh, const void *v, size_t len) 2719{ 2720 return sshbuf_put_string(ssh->state->outgoing_packet, v, len); 2721} 2722 2723int 2724sshpkt_put_cstring(struct ssh *ssh, const void *v) 2725{ 2726 return sshbuf_put_cstring(ssh->state->outgoing_packet, v); 2727} 2728 2729int 2730sshpkt_put_stringb(struct ssh *ssh, const struct sshbuf *v) 2731{ 2732 return sshbuf_put_stringb(ssh->state->outgoing_packet, v); 2733} 2734 2735int 2736sshpkt_put_ec(struct ssh *ssh, const EC_POINT *v, const EC_GROUP *g) 2737{ 2738 return sshbuf_put_ec(ssh->state->outgoing_packet, v, g); 2739} 2740 2741int 2742sshpkt_put_bignum1(struct ssh *ssh, const BIGNUM *v) 2743{ 2744 return sshbuf_put_bignum1(ssh->state->outgoing_packet, v); 2745} 2746 2747int 2748sshpkt_put_bignum2(struct ssh *ssh, const BIGNUM *v) 2749{ 2750 return sshbuf_put_bignum2(ssh->state->outgoing_packet, v); 2751} 2752 2753/* fetch data from the incoming packet */ 2754 2755int 2756sshpkt_get(struct ssh *ssh, void *valp, size_t len) 2757{ 2758 return sshbuf_get(ssh->state->incoming_packet, valp, len); 2759} 2760 2761int 2762sshpkt_get_u8(struct ssh *ssh, u_char *valp) 2763{ 2764 return sshbuf_get_u8(ssh->state->incoming_packet, valp); 2765} 2766 2767int 2768sshpkt_get_u32(struct ssh *ssh, u_int32_t *valp) 2769{ 2770 return sshbuf_get_u32(ssh->state->incoming_packet, valp); 2771} 2772 2773int 2774sshpkt_get_u64(struct ssh *ssh, u_int64_t *valp) 2775{ 2776 return sshbuf_get_u64(ssh->state->incoming_packet, valp); 2777} 2778 2779int 2780sshpkt_get_string(struct ssh *ssh, u_char **valp, size_t *lenp) 2781{ 2782 return sshbuf_get_string(ssh->state->incoming_packet, valp, lenp); 2783} 2784 2785int 2786sshpkt_get_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp) 2787{ 2788 return sshbuf_get_string_direct(ssh->state->incoming_packet, valp, lenp); 2789} 2790 2791int 2792sshpkt_get_cstring(struct ssh *ssh, char **valp, size_t *lenp) 2793{ 2794 return sshbuf_get_cstring(ssh->state->incoming_packet, valp, lenp); 2795} 2796 2797int 2798sshpkt_get_ec(struct ssh *ssh, EC_POINT *v, const EC_GROUP *g) 2799{ 2800 return sshbuf_get_ec(ssh->state->incoming_packet, v, g); 2801} 2802 2803int 2804sshpkt_get_bignum1(struct ssh *ssh, BIGNUM *v) 2805{ 2806 return sshbuf_get_bignum1(ssh->state->incoming_packet, v); 2807} 2808 2809int 2810sshpkt_get_bignum2(struct ssh *ssh, BIGNUM *v) 2811{ 2812 return sshbuf_get_bignum2(ssh->state->incoming_packet, v); 2813} 2814 2815int 2816sshpkt_get_end(struct ssh *ssh) 2817{ 2818 if (sshbuf_len(ssh->state->incoming_packet) > 0) 2819 return SSH_ERR_UNEXPECTED_TRAILING_DATA; 2820 return 0; 2821} 2822 2823const u_char * 2824sshpkt_ptr(struct ssh *ssh, size_t *lenp) 2825{ 2826 if (lenp != NULL) 2827 *lenp = sshbuf_len(ssh->state->incoming_packet); 2828 return sshbuf_ptr(ssh->state->incoming_packet); 2829} 2830 2831/* start a new packet */ 2832 2833int 2834sshpkt_start(struct ssh *ssh, u_char type) 2835{ 2836 u_char buf[9]; 2837 int len; 2838 2839 DBG(debug("packet_start[%d]", type)); 2840 len = compat20 ? 6 : 9; 2841 memset(buf, 0, len - 1); 2842 buf[len - 1] = type; 2843 sshbuf_reset(ssh->state->outgoing_packet); 2844 return sshbuf_put(ssh->state->outgoing_packet, buf, len); 2845} 2846 2847/* send it */ 2848 2849int 2850sshpkt_sendx(struct ssh *ssh) 2851{ 2852 if (compat20) 2853 return ssh_packet_send2(ssh); 2854 else 2855 return ssh_packet_send1(ssh); 2856} 2857 2858int 2859sshpkt_send(struct ssh *ssh) 2860{ 2861 int r = sshpkt_sendx(ssh); 2862 return r < 0 ? r : 0; 2863} 2864 2865int 2866sshpkt_disconnect(struct ssh *ssh, const char *fmt,...) 2867{ 2868 char buf[1024]; 2869 va_list args; 2870 int r; 2871 2872 va_start(args, fmt); 2873 vsnprintf(buf, sizeof(buf), fmt, args); 2874 va_end(args); 2875 2876 if (compat20) { 2877 if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 || 2878 (r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_PROTOCOL_ERROR)) != 0 || 2879 (r = sshpkt_put_cstring(ssh, buf)) != 0 || 2880 (r = sshpkt_put_cstring(ssh, "")) != 0 || 2881 (r = sshpkt_send(ssh)) != 0) 2882 return r; 2883 } else { 2884 if ((r = sshpkt_start(ssh, SSH_MSG_DISCONNECT)) != 0 || 2885 (r = sshpkt_put_cstring(ssh, buf)) != 0 || 2886 (r = sshpkt_send(ssh)) != 0) 2887 return r; 2888 } 2889 return 0; 2890} 2891 2892/* roundup current message to pad bytes */ 2893int 2894sshpkt_add_padding(struct ssh *ssh, u_char pad) 2895{ 2896 ssh->state->extra_pad = pad; 2897 return 0; 2898} 2899 2900int 2901ssh_packet_authentication_state(void) 2902{ 2903 return active_state->state->after_authentication; 2904} 2905