packet.c revision 1.46
1/* $NetBSD: packet.c,v 1.46 2022/02/23 19:07:20 christos Exp $ */ 2/* $OpenBSD: packet.c,v 1.307 2022/01/22 00:49:34 djm 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 1.46 2022/02/23 19:07:20 christos Exp $"); 43 44#include <sys/param.h> /* MIN roundup */ 45#include <sys/types.h> 46#include <sys/queue.h> 47#include <sys/socket.h> 48#include <sys/time.h> 49#include <netinet/in.h> 50#include <netinet/ip.h> 51 52#include <errno.h> 53#include <netdb.h> 54#include <stdarg.h> 55#include <stdio.h> 56#include <stdlib.h> 57#include <string.h> 58#include <unistd.h> 59#include <limits.h> 60#include <poll.h> 61#include <signal.h> 62#include <time.h> 63 64#ifdef WITH_ZLIB 65#include <zlib.h> 66#endif 67 68#include "xmalloc.h" 69#include "compat.h" 70#include "ssh2.h" 71#include "cipher.h" 72#include "sshkey.h" 73#include "kex.h" 74#include "digest.h" 75#include "mac.h" 76#include "log.h" 77#include "canohost.h" 78#include "misc.h" 79#include "channels.h" 80#include "ssh.h" 81#include "packet.h" 82#include "ssherr.h" 83#include "sshbuf.h" 84 85#ifdef PACKET_DEBUG 86#define DBG(x) x 87#else 88#define DBG(x) 89#endif 90 91#define PACKET_MAX_SIZE (256 * 1024) 92 93struct packet_state { 94 u_int32_t seqnr; 95 u_int32_t packets; 96 u_int64_t blocks; 97 u_int64_t bytes; 98}; 99 100struct packet { 101 TAILQ_ENTRY(packet) next; 102 u_char type; 103 struct sshbuf *payload; 104}; 105 106struct session_state { 107 /* 108 * This variable contains the file descriptors used for 109 * communicating with the other side. connection_in is used for 110 * reading; connection_out for writing. These can be the same 111 * descriptor, in which case it is assumed to be a socket. 112 */ 113 int connection_in; 114 int connection_out; 115 116 /* Protocol flags for the remote side. */ 117 u_int remote_protocol_flags; 118 119 /* Encryption context for receiving data. Only used for decryption. */ 120 struct sshcipher_ctx *receive_context; 121 122 /* Encryption context for sending data. Only used for encryption. */ 123 struct sshcipher_ctx *send_context; 124 125 /* Buffer for raw input data from the socket. */ 126 struct sshbuf *input; 127 128 /* Buffer for raw output data going to the socket. */ 129 struct sshbuf *output; 130 131 /* Buffer for the partial outgoing packet being constructed. */ 132 struct sshbuf *outgoing_packet; 133 134 /* Buffer for the incoming packet currently being processed. */ 135 struct sshbuf *incoming_packet; 136 137 /* Scratch buffer for packet compression/decompression. */ 138 struct sshbuf *compression_buffer; 139 140#ifdef WITH_ZLIB 141 /* Incoming/outgoing compression dictionaries */ 142 z_stream compression_in_stream; 143 z_stream compression_out_stream; 144#endif 145 int compression_in_started; 146 int compression_out_started; 147 int compression_in_failures; 148 int compression_out_failures; 149 150 /* default maximum packet size */ 151 u_int max_packet_size; 152 153 /* Flag indicating whether this module has been initialized. */ 154 int initialized; 155 156 /* Set to true if the connection is interactive. */ 157 int interactive_mode; 158 159 /* Set to true if we are the server side. */ 160 int server_side; 161 162 /* Set to true if we are authenticated. */ 163 int after_authentication; 164 165 int keep_alive_timeouts; 166 167 /* The maximum time that we will wait to send or receive a packet */ 168 int packet_timeout_ms; 169 170 /* Session key information for Encryption and MAC */ 171 struct newkeys *newkeys[MODE_MAX]; 172 struct packet_state p_read, p_send; 173 174 /* Volume-based rekeying */ 175 u_int64_t max_blocks_in, max_blocks_out, rekey_limit; 176 177 /* Time-based rekeying */ 178 u_int32_t rekey_interval; /* how often in seconds */ 179 time_t rekey_time; /* time of last rekeying */ 180 181 /* roundup current message to extra_pad bytes */ 182 u_char extra_pad; 183 184 /* XXX discard incoming data after MAC error */ 185 u_int packet_discard; 186 size_t packet_discard_mac_already; 187 struct sshmac *packet_discard_mac; 188 189 /* Used in packet_read_poll2() */ 190 u_int packlen; 191 192 /* Used in packet_send2 */ 193 int rekeying; 194 195 /* Used in ssh_packet_send_mux() */ 196 int mux; 197 198 /* Used in packet_set_interactive */ 199 int set_interactive_called; 200 201 /* Used in packet_set_maxsize */ 202 int set_maxsize_called; 203 204 /* One-off warning about weak ciphers */ 205 int cipher_warning_done; 206 207 /* Hook for fuzzing inbound packets */ 208 ssh_packet_hook_fn *hook_in; 209 void *hook_in_ctx; 210 211 TAILQ_HEAD(, packet) outgoing; 212}; 213 214struct ssh * 215ssh_alloc_session_state(void) 216{ 217 struct ssh *ssh = NULL; 218 struct session_state *state = NULL; 219 220 if ((ssh = calloc(1, sizeof(*ssh))) == NULL || 221 (state = calloc(1, sizeof(*state))) == NULL || 222 (ssh->kex = kex_new()) == NULL || 223 (state->input = sshbuf_new()) == NULL || 224 (state->output = sshbuf_new()) == NULL || 225 (state->outgoing_packet = sshbuf_new()) == NULL || 226 (state->incoming_packet = sshbuf_new()) == NULL) 227 goto fail; 228 TAILQ_INIT(&state->outgoing); 229 TAILQ_INIT(&ssh->private_keys); 230 TAILQ_INIT(&ssh->public_keys); 231 state->connection_in = -1; 232 state->connection_out = -1; 233 state->max_packet_size = 32768; 234 state->packet_timeout_ms = -1; 235 state->p_send.packets = state->p_read.packets = 0; 236 state->initialized = 1; 237 /* 238 * ssh_packet_send2() needs to queue packets until 239 * we've done the initial key exchange. 240 */ 241 state->rekeying = 1; 242 ssh->state = state; 243 return ssh; 244 fail: 245 if (ssh) { 246 kex_free(ssh->kex); 247 free(ssh); 248 } 249 if (state) { 250 sshbuf_free(state->input); 251 sshbuf_free(state->output); 252 sshbuf_free(state->incoming_packet); 253 sshbuf_free(state->outgoing_packet); 254 free(state); 255 } 256 return NULL; 257} 258 259void 260ssh_packet_set_input_hook(struct ssh *ssh, ssh_packet_hook_fn *hook, void *ctx) 261{ 262 ssh->state->hook_in = hook; 263 ssh->state->hook_in_ctx = ctx; 264} 265 266/* Returns nonzero if rekeying is in progress */ 267int 268ssh_packet_is_rekeying(struct ssh *ssh) 269{ 270 return ssh->state->rekeying || 271 (ssh->kex != NULL && ssh->kex->done == 0); 272} 273 274/* 275 * Sets the descriptors used for communication. 276 */ 277struct ssh * 278ssh_packet_set_connection(struct ssh *ssh, int fd_in, int fd_out) 279{ 280 struct session_state *state; 281 const struct sshcipher *none = cipher_by_name("none"); 282 int r; 283 284 if (none == NULL) { 285 error_f("cannot load cipher 'none'"); 286 return NULL; 287 } 288 if (ssh == NULL) 289 ssh = ssh_alloc_session_state(); 290 if (ssh == NULL) { 291 error_f("could not allocate state"); 292 return NULL; 293 } 294 state = ssh->state; 295 state->connection_in = fd_in; 296 state->connection_out = fd_out; 297 if ((r = cipher_init(&state->send_context, none, 298 (const u_char *)"", 0, NULL, 0, CIPHER_ENCRYPT)) != 0 || 299 (r = cipher_init(&state->receive_context, none, 300 (const u_char *)"", 0, NULL, 0, CIPHER_DECRYPT)) != 0) { 301 error_fr(r, "cipher_init failed"); 302 free(ssh); /* XXX need ssh_free_session_state? */ 303 return NULL; 304 } 305 state->newkeys[MODE_IN] = state->newkeys[MODE_OUT] = NULL; 306 /* 307 * Cache the IP address of the remote connection for use in error 308 * messages that might be generated after the connection has closed. 309 */ 310 (void)ssh_remote_ipaddr(ssh); 311 return ssh; 312} 313 314void 315ssh_packet_set_timeout(struct ssh *ssh, int timeout, int count) 316{ 317 struct session_state *state = ssh->state; 318 319 if (timeout <= 0 || count <= 0) { 320 state->packet_timeout_ms = -1; 321 return; 322 } 323 if ((INT_MAX / 1000) / count < timeout) 324 state->packet_timeout_ms = INT_MAX; 325 else 326 state->packet_timeout_ms = timeout * count * 1000; 327} 328 329void 330ssh_packet_set_mux(struct ssh *ssh) 331{ 332 ssh->state->mux = 1; 333 ssh->state->rekeying = 0; 334 kex_free(ssh->kex); 335 ssh->kex = NULL; 336} 337 338int 339ssh_packet_get_mux(struct ssh *ssh) 340{ 341 return ssh->state->mux; 342} 343 344int 345ssh_packet_set_log_preamble(struct ssh *ssh, const char *fmt, ...) 346{ 347 va_list args; 348 int r; 349 350 free(ssh->log_preamble); 351 if (fmt == NULL) 352 ssh->log_preamble = NULL; 353 else { 354 va_start(args, fmt); 355 r = vasprintf(&ssh->log_preamble, fmt, args); 356 va_end(args); 357 if (r < 0 || ssh->log_preamble == NULL) 358 return SSH_ERR_ALLOC_FAIL; 359 } 360 return 0; 361} 362 363int 364ssh_packet_stop_discard(struct ssh *ssh) 365{ 366 struct session_state *state = ssh->state; 367 int r; 368 369 if (state->packet_discard_mac) { 370 char buf[1024]; 371 size_t dlen = PACKET_MAX_SIZE; 372 373 if (dlen > state->packet_discard_mac_already) 374 dlen -= state->packet_discard_mac_already; 375 memset(buf, 'a', sizeof(buf)); 376 while (sshbuf_len(state->incoming_packet) < dlen) 377 if ((r = sshbuf_put(state->incoming_packet, buf, 378 sizeof(buf))) != 0) 379 return r; 380 (void) mac_compute(state->packet_discard_mac, 381 state->p_read.seqnr, 382 sshbuf_ptr(state->incoming_packet), dlen, 383 NULL, 0); 384 } 385 logit("Finished discarding for %.200s port %d", 386 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 387 return SSH_ERR_MAC_INVALID; 388} 389 390static int 391ssh_packet_start_discard(struct ssh *ssh, struct sshenc *enc, 392 struct sshmac *mac, size_t mac_already, u_int discard) 393{ 394 struct session_state *state = ssh->state; 395 int r; 396 397 if (enc == NULL || !cipher_is_cbc(enc->cipher) || (mac && mac->etm)) { 398 if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0) 399 return r; 400 return SSH_ERR_MAC_INVALID; 401 } 402 /* 403 * Record number of bytes over which the mac has already 404 * been computed in order to minimize timing attacks. 405 */ 406 if (mac && mac->enabled) { 407 state->packet_discard_mac = mac; 408 state->packet_discard_mac_already = mac_already; 409 } 410 if (sshbuf_len(state->input) >= discard) 411 return ssh_packet_stop_discard(ssh); 412 state->packet_discard = discard - sshbuf_len(state->input); 413 return 0; 414} 415 416/* Returns 1 if remote host is connected via socket, 0 if not. */ 417 418int 419ssh_packet_connection_is_on_socket(struct ssh *ssh) 420{ 421 struct session_state *state; 422 struct sockaddr_storage from, to; 423 socklen_t fromlen, tolen; 424 425 if (ssh == NULL || ssh->state == NULL) 426 return 0; 427 428 state = ssh->state; 429 if (state->connection_in == -1 || state->connection_out == -1) 430 return 0; 431 /* filedescriptors in and out are the same, so it's a socket */ 432 if (state->connection_in == state->connection_out) 433 return 1; 434 fromlen = sizeof(from); 435 memset(&from, 0, sizeof(from)); 436 if (getpeername(state->connection_in, (struct sockaddr *)&from, 437 &fromlen) == -1) 438 return 0; 439 tolen = sizeof(to); 440 memset(&to, 0, sizeof(to)); 441 if (getpeername(state->connection_out, (struct sockaddr *)&to, 442 &tolen) == -1) 443 return 0; 444 if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0) 445 return 0; 446 if (from.ss_family != AF_INET && from.ss_family != AF_INET6) 447 return 0; 448 return 1; 449} 450 451void 452ssh_packet_get_bytes(struct ssh *ssh, u_int64_t *ibytes, u_int64_t *obytes) 453{ 454 if (ibytes) 455 *ibytes = ssh->state->p_read.bytes; 456 if (obytes) 457 *obytes = ssh->state->p_send.bytes; 458} 459 460int 461ssh_packet_connection_af(struct ssh *ssh) 462{ 463 return get_sock_af(ssh->state->connection_out); 464} 465 466/* Sets the connection into non-blocking mode. */ 467 468void 469ssh_packet_set_nonblocking(struct ssh *ssh) 470{ 471 /* Set the socket into non-blocking mode. */ 472 set_nonblock(ssh->state->connection_in); 473 474 if (ssh->state->connection_out != ssh->state->connection_in) 475 set_nonblock(ssh->state->connection_out); 476} 477 478/* Returns the socket used for reading. */ 479 480int 481ssh_packet_get_connection_in(struct ssh *ssh) 482{ 483 return ssh->state->connection_in; 484} 485 486/* Returns the descriptor used for writing. */ 487 488int 489ssh_packet_get_connection_out(struct ssh *ssh) 490{ 491 return ssh->state->connection_out; 492} 493 494/* 495 * Returns the IP-address of the remote host as a string. The returned 496 * string must not be freed. 497 */ 498 499const char * 500ssh_remote_ipaddr(struct ssh *ssh) 501{ 502 int sock; 503 504 /* Check whether we have cached the ipaddr. */ 505 if (ssh->remote_ipaddr == NULL) { 506 if (ssh_packet_connection_is_on_socket(ssh)) { 507 sock = ssh->state->connection_in; 508 ssh->remote_ipaddr = get_peer_ipaddr(sock); 509 ssh->remote_port = get_peer_port(sock); 510 ssh->local_ipaddr = get_local_ipaddr(sock); 511 ssh->local_port = get_local_port(sock); 512 } else { 513 ssh->remote_ipaddr = xstrdup("UNKNOWN"); 514 ssh->remote_port = 65535; 515 ssh->local_ipaddr = xstrdup("UNKNOWN"); 516 ssh->local_port = 65535; 517 } 518 } 519 return ssh->remote_ipaddr; 520} 521 522/* Returns the port number of the remote host. */ 523 524int 525ssh_remote_port(struct ssh *ssh) 526{ 527 (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */ 528 return ssh->remote_port; 529} 530 531/* 532 * Returns the IP-address of the local host as a string. The returned 533 * string must not be freed. 534 */ 535 536const char * 537ssh_local_ipaddr(struct ssh *ssh) 538{ 539 (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */ 540 return ssh->local_ipaddr; 541} 542 543/* Returns the port number of the local host. */ 544 545int 546ssh_local_port(struct ssh *ssh) 547{ 548 (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */ 549 return ssh->local_port; 550} 551 552/* Returns the routing domain of the input socket, or NULL if unavailable */ 553const char * 554ssh_packet_rdomain_in(struct ssh *ssh) 555{ 556 if (ssh->rdomain_in != NULL) 557 return ssh->rdomain_in; 558 if (!ssh_packet_connection_is_on_socket(ssh)) 559 return NULL; 560 ssh->rdomain_in = get_rdomain(ssh->state->connection_in); 561 return ssh->rdomain_in; 562} 563 564/* Closes the connection and clears and frees internal data structures. */ 565 566static void 567ssh_packet_close_internal(struct ssh *ssh, int do_close) 568{ 569 struct session_state *state = ssh->state; 570 u_int mode; 571 572 if (!state->initialized) 573 return; 574 state->initialized = 0; 575 if (do_close) { 576 if (state->connection_in == state->connection_out) { 577 close(state->connection_out); 578 } else { 579 close(state->connection_in); 580 close(state->connection_out); 581 } 582 } 583 sshbuf_free(state->input); 584 sshbuf_free(state->output); 585 sshbuf_free(state->outgoing_packet); 586 sshbuf_free(state->incoming_packet); 587 for (mode = 0; mode < MODE_MAX; mode++) { 588 kex_free_newkeys(state->newkeys[mode]); /* current keys */ 589 state->newkeys[mode] = NULL; 590 ssh_clear_newkeys(ssh, mode); /* next keys */ 591 } 592#ifdef WITH_ZLIB 593 /* compression state is in shared mem, so we can only release it once */ 594 if (do_close && state->compression_buffer) { 595 sshbuf_free(state->compression_buffer); 596 if (state->compression_out_started) { 597 z_streamp stream = &state->compression_out_stream; 598 debug("compress outgoing: " 599 "raw data %llu, compressed %llu, factor %.2f", 600 (unsigned long long)stream->total_in, 601 (unsigned long long)stream->total_out, 602 stream->total_in == 0 ? 0.0 : 603 (double) stream->total_out / stream->total_in); 604 if (state->compression_out_failures == 0) 605 deflateEnd(stream); 606 } 607 if (state->compression_in_started) { 608 z_streamp stream = &state->compression_in_stream; 609 debug("compress incoming: " 610 "raw data %llu, compressed %llu, factor %.2f", 611 (unsigned long long)stream->total_out, 612 (unsigned long long)stream->total_in, 613 stream->total_out == 0 ? 0.0 : 614 (double) stream->total_in / stream->total_out); 615 if (state->compression_in_failures == 0) 616 inflateEnd(stream); 617 } 618 } 619#endif /* WITH_ZLIB */ 620 cipher_free(state->send_context); 621 cipher_free(state->receive_context); 622 state->send_context = state->receive_context = NULL; 623 if (do_close) { 624 free(ssh->local_ipaddr); 625 ssh->local_ipaddr = NULL; 626 free(ssh->remote_ipaddr); 627 ssh->remote_ipaddr = NULL; 628 free(ssh->state); 629 ssh->state = NULL; 630 kex_free(ssh->kex); 631 ssh->kex = NULL; 632 } 633} 634 635void 636ssh_packet_close(struct ssh *ssh) 637{ 638 ssh_packet_close_internal(ssh, 1); 639} 640 641void 642ssh_packet_clear_keys(struct ssh *ssh) 643{ 644 ssh_packet_close_internal(ssh, 0); 645} 646 647/* Sets remote side protocol flags. */ 648 649void 650ssh_packet_set_protocol_flags(struct ssh *ssh, u_int protocol_flags) 651{ 652 ssh->state->remote_protocol_flags = protocol_flags; 653} 654 655/* Returns the remote protocol flags set earlier by the above function. */ 656 657u_int 658ssh_packet_get_protocol_flags(struct ssh *ssh) 659{ 660 return ssh->state->remote_protocol_flags; 661} 662 663/* 664 * Starts packet compression from the next packet on in both directions. 665 * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip. 666 */ 667 668static int 669ssh_packet_init_compression(struct ssh *ssh) 670{ 671 if (!ssh->state->compression_buffer && 672 ((ssh->state->compression_buffer = sshbuf_new()) == NULL)) 673 return SSH_ERR_ALLOC_FAIL; 674 return 0; 675} 676 677#ifdef WITH_ZLIB 678static int 679start_compression_out(struct ssh *ssh, int level) 680{ 681 if (level < 1 || level > 9) 682 return SSH_ERR_INVALID_ARGUMENT; 683 debug("Enabling compression at level %d.", level); 684 if (ssh->state->compression_out_started == 1) 685 deflateEnd(&ssh->state->compression_out_stream); 686 switch (deflateInit(&ssh->state->compression_out_stream, level)) { 687 case Z_OK: 688 ssh->state->compression_out_started = 1; 689 break; 690 case Z_MEM_ERROR: 691 return SSH_ERR_ALLOC_FAIL; 692 default: 693 return SSH_ERR_INTERNAL_ERROR; 694 } 695 return 0; 696} 697 698static int 699start_compression_in(struct ssh *ssh) 700{ 701 if (ssh->state->compression_in_started == 1) 702 inflateEnd(&ssh->state->compression_in_stream); 703 switch (inflateInit(&ssh->state->compression_in_stream)) { 704 case Z_OK: 705 ssh->state->compression_in_started = 1; 706 break; 707 case Z_MEM_ERROR: 708 return SSH_ERR_ALLOC_FAIL; 709 default: 710 return SSH_ERR_INTERNAL_ERROR; 711 } 712 return 0; 713} 714 715/* XXX remove need for separate compression buffer */ 716static int 717compress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out) 718{ 719 u_char buf[4096]; 720 int r, status; 721 722 if (ssh->state->compression_out_started != 1) 723 return SSH_ERR_INTERNAL_ERROR; 724 725 /* This case is not handled below. */ 726 if (sshbuf_len(in) == 0) 727 return 0; 728 729 /* Input is the contents of the input buffer. */ 730 if ((ssh->state->compression_out_stream.next_in = 731 sshbuf_mutable_ptr(in)) == NULL) 732 return SSH_ERR_INTERNAL_ERROR; 733 ssh->state->compression_out_stream.avail_in = sshbuf_len(in); 734 735 /* Loop compressing until deflate() returns with avail_out != 0. */ 736 do { 737 /* Set up fixed-size output buffer. */ 738 ssh->state->compression_out_stream.next_out = buf; 739 ssh->state->compression_out_stream.avail_out = sizeof(buf); 740 741 /* Compress as much data into the buffer as possible. */ 742 status = deflate(&ssh->state->compression_out_stream, 743 Z_PARTIAL_FLUSH); 744 switch (status) { 745 case Z_MEM_ERROR: 746 return SSH_ERR_ALLOC_FAIL; 747 case Z_OK: 748 /* Append compressed data to output_buffer. */ 749 if ((r = sshbuf_put(out, buf, sizeof(buf) - 750 ssh->state->compression_out_stream.avail_out)) != 0) 751 return r; 752 break; 753 case Z_STREAM_ERROR: 754 default: 755 ssh->state->compression_out_failures++; 756 return SSH_ERR_INVALID_FORMAT; 757 } 758 } while (ssh->state->compression_out_stream.avail_out == 0); 759 return 0; 760} 761 762static int 763uncompress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out) 764{ 765 u_char buf[4096]; 766 int r, status; 767 768 if (ssh->state->compression_in_started != 1) 769 return SSH_ERR_INTERNAL_ERROR; 770 771 if ((ssh->state->compression_in_stream.next_in = 772 sshbuf_mutable_ptr(in)) == NULL) 773 return SSH_ERR_INTERNAL_ERROR; 774 ssh->state->compression_in_stream.avail_in = sshbuf_len(in); 775 776 for (;;) { 777 /* Set up fixed-size output buffer. */ 778 ssh->state->compression_in_stream.next_out = buf; 779 ssh->state->compression_in_stream.avail_out = sizeof(buf); 780 781 status = inflate(&ssh->state->compression_in_stream, 782 Z_SYNC_FLUSH); 783 switch (status) { 784 case Z_OK: 785 if ((r = sshbuf_put(out, buf, sizeof(buf) - 786 ssh->state->compression_in_stream.avail_out)) != 0) 787 return r; 788 break; 789 case Z_BUF_ERROR: 790 /* 791 * Comments in zlib.h say that we should keep calling 792 * inflate() until we get an error. This appears to 793 * be the error that we get. 794 */ 795 return 0; 796 case Z_DATA_ERROR: 797 return SSH_ERR_INVALID_FORMAT; 798 case Z_MEM_ERROR: 799 return SSH_ERR_ALLOC_FAIL; 800 case Z_STREAM_ERROR: 801 default: 802 ssh->state->compression_in_failures++; 803 return SSH_ERR_INTERNAL_ERROR; 804 } 805 } 806 /* NOTREACHED */ 807} 808 809#else /* WITH_ZLIB */ 810 811static int 812start_compression_out(struct ssh *ssh, int level) 813{ 814 return SSH_ERR_INTERNAL_ERROR; 815} 816 817static int 818start_compression_in(struct ssh *ssh) 819{ 820 return SSH_ERR_INTERNAL_ERROR; 821} 822 823static int 824compress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out) 825{ 826 return SSH_ERR_INTERNAL_ERROR; 827} 828 829static int 830uncompress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out) 831{ 832 return SSH_ERR_INTERNAL_ERROR; 833} 834#endif /* WITH_ZLIB */ 835 836void 837ssh_clear_newkeys(struct ssh *ssh, int mode) 838{ 839 if (ssh->kex && ssh->kex->newkeys[mode]) { 840 kex_free_newkeys(ssh->kex->newkeys[mode]); 841 ssh->kex->newkeys[mode] = NULL; 842 } 843} 844 845int 846ssh_set_newkeys(struct ssh *ssh, int mode) 847{ 848 struct session_state *state = ssh->state; 849 struct sshenc *enc; 850 struct sshmac *mac; 851 struct sshcomp *comp; 852 struct sshcipher_ctx **ccp; 853 struct packet_state *ps; 854 u_int64_t *max_blocks; 855 const char *wmsg; 856 int r, crypt_type; 857 const char *dir = mode == MODE_OUT ? "out" : "in"; 858 859 debug2_f("mode %d", mode); 860 861 if (mode == MODE_OUT) { 862 ccp = &state->send_context; 863 crypt_type = CIPHER_ENCRYPT; 864 ps = &state->p_send; 865 max_blocks = &state->max_blocks_out; 866 } else { 867 ccp = &state->receive_context; 868 crypt_type = CIPHER_DECRYPT; 869 ps = &state->p_read; 870 max_blocks = &state->max_blocks_in; 871 } 872 if (state->newkeys[mode] != NULL) { 873 debug_f("rekeying %s, input %llu bytes %llu blocks, " 874 "output %llu bytes %llu blocks", dir, 875 (unsigned long long)state->p_read.bytes, 876 (unsigned long long)state->p_read.blocks, 877 (unsigned long long)state->p_send.bytes, 878 (unsigned long long)state->p_send.blocks); 879 kex_free_newkeys(state->newkeys[mode]); 880 state->newkeys[mode] = NULL; 881 } 882 /* note that both bytes and the seqnr are not reset */ 883 ps->packets = ps->blocks = 0; 884 /* move newkeys from kex to state */ 885 if ((state->newkeys[mode] = ssh->kex->newkeys[mode]) == NULL) 886 return SSH_ERR_INTERNAL_ERROR; 887 ssh->kex->newkeys[mode] = NULL; 888 enc = &state->newkeys[mode]->enc; 889 mac = &state->newkeys[mode]->mac; 890 comp = &state->newkeys[mode]->comp; 891 if (cipher_authlen(enc->cipher) == 0) { 892 if ((r = mac_init(mac)) != 0) 893 return r; 894 } 895 mac->enabled = 1; 896 DBG(debug_f("cipher_init: %s", dir)); 897 cipher_free(*ccp); 898 *ccp = NULL; 899 if ((r = cipher_init(ccp, enc->cipher, enc->key, enc->key_len, 900 enc->iv, enc->iv_len, crypt_type)) != 0) 901 return r; 902 if (!state->cipher_warning_done && 903 (wmsg = cipher_warning_message(*ccp)) != NULL) { 904 error("Warning: %s", wmsg); 905 state->cipher_warning_done = 1; 906 } 907 /* Deleting the keys does not gain extra security */ 908 /* explicit_bzero(enc->iv, enc->block_size); 909 explicit_bzero(enc->key, enc->key_len); 910 explicit_bzero(mac->key, mac->key_len); */ 911 if ((comp->type == COMP_ZLIB || 912 (comp->type == COMP_DELAYED && 913 state->after_authentication)) && comp->enabled == 0) { 914 if ((r = ssh_packet_init_compression(ssh)) < 0) 915 return r; 916 if (mode == MODE_OUT) { 917 if ((r = start_compression_out(ssh, 6)) != 0) 918 return r; 919 } else { 920 if ((r = start_compression_in(ssh)) != 0) 921 return r; 922 } 923 comp->enabled = 1; 924 } 925 /* 926 * The 2^(blocksize*2) limit is too expensive for 3DES, 927 * so enforce a 1GB limit for small blocksizes. 928 * See RFC4344 section 3.2. 929 */ 930 if (enc->block_size >= 16) 931 *max_blocks = (u_int64_t)1 << (enc->block_size*2); 932 else 933 *max_blocks = ((u_int64_t)1 << 30) / enc->block_size; 934 if (state->rekey_limit) 935 *max_blocks = MINIMUM(*max_blocks, 936 state->rekey_limit / enc->block_size); 937 debug("rekey %s after %llu blocks", dir, 938 (unsigned long long)*max_blocks); 939 return 0; 940} 941 942#define MAX_PACKETS (1U<<31) 943static int 944ssh_packet_need_rekeying(struct ssh *ssh, u_int outbound_packet_len) 945{ 946 struct session_state *state = ssh->state; 947 u_int32_t out_blocks; 948 949 /* XXX client can't cope with rekeying pre-auth */ 950 if (!state->after_authentication) 951 return 0; 952 953 /* Haven't keyed yet or KEX in progress. */ 954 if (ssh_packet_is_rekeying(ssh)) 955 return 0; 956 957 /* Peer can't rekey */ 958 if (ssh->compat & SSH_BUG_NOREKEY) 959 return 0; 960 961 /* 962 * Permit one packet in or out per rekey - this allows us to 963 * make progress when rekey limits are very small. 964 */ 965 if (state->p_send.packets == 0 && state->p_read.packets == 0) 966 return 0; 967 968 /* Time-based rekeying */ 969 if (state->rekey_interval != 0 && 970 (int64_t)state->rekey_time + state->rekey_interval <= monotime()) 971 return 1; 972 973 /* 974 * Always rekey when MAX_PACKETS sent in either direction 975 * As per RFC4344 section 3.1 we do this after 2^31 packets. 976 */ 977 if (state->p_send.packets > MAX_PACKETS || 978 state->p_read.packets > MAX_PACKETS) 979 return 1; 980 981 /* Rekey after (cipher-specific) maximum blocks */ 982 out_blocks = ROUNDUP(outbound_packet_len, 983 state->newkeys[MODE_OUT]->enc.block_size); 984 return (state->max_blocks_out && 985 (state->p_send.blocks + out_blocks > state->max_blocks_out)) || 986 (state->max_blocks_in && 987 (state->p_read.blocks > state->max_blocks_in)); 988} 989 990int 991ssh_packet_check_rekey(struct ssh *ssh) 992{ 993 if (!ssh_packet_need_rekeying(ssh, 0)) 994 return 0; 995 debug3_f("rekex triggered"); 996 return kex_start_rekex(ssh); 997} 998 999/* 1000 * Delayed compression for SSH2 is enabled after authentication: 1001 * This happens on the server side after a SSH2_MSG_USERAUTH_SUCCESS is sent, 1002 * and on the client side after a SSH2_MSG_USERAUTH_SUCCESS is received. 1003 */ 1004static int 1005ssh_packet_enable_delayed_compress(struct ssh *ssh) 1006{ 1007 struct session_state *state = ssh->state; 1008 struct sshcomp *comp = NULL; 1009 int r, mode; 1010 1011 /* 1012 * Remember that we are past the authentication step, so rekeying 1013 * with COMP_DELAYED will turn on compression immediately. 1014 */ 1015 state->after_authentication = 1; 1016 for (mode = 0; mode < MODE_MAX; mode++) { 1017 /* protocol error: USERAUTH_SUCCESS received before NEWKEYS */ 1018 if (state->newkeys[mode] == NULL) 1019 continue; 1020 comp = &state->newkeys[mode]->comp; 1021 if (comp && !comp->enabled && comp->type == COMP_DELAYED) { 1022 if ((r = ssh_packet_init_compression(ssh)) != 0) 1023 return r; 1024 if (mode == MODE_OUT) { 1025 if ((r = start_compression_out(ssh, 6)) != 0) 1026 return r; 1027 } else { 1028 if ((r = start_compression_in(ssh)) != 0) 1029 return r; 1030 } 1031 comp->enabled = 1; 1032 } 1033 } 1034 return 0; 1035} 1036 1037/* Used to mute debug logging for noisy packet types */ 1038int 1039ssh_packet_log_type(u_char type) 1040{ 1041 switch (type) { 1042 case SSH2_MSG_CHANNEL_DATA: 1043 case SSH2_MSG_CHANNEL_EXTENDED_DATA: 1044 case SSH2_MSG_CHANNEL_WINDOW_ADJUST: 1045 return 0; 1046 default: 1047 return 1; 1048 } 1049} 1050 1051/* 1052 * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue) 1053 */ 1054int 1055ssh_packet_send2_wrapped(struct ssh *ssh) 1056{ 1057 struct session_state *state = ssh->state; 1058 u_char type, *cp, macbuf[SSH_DIGEST_MAX_LENGTH]; 1059 u_char tmp, padlen, pad = 0; 1060 u_int authlen = 0, aadlen = 0; 1061 u_int len; 1062 struct sshenc *enc = NULL; 1063 struct sshmac *mac = NULL; 1064 struct sshcomp *comp = NULL; 1065 int r, block_size; 1066 1067 if (state->newkeys[MODE_OUT] != NULL) { 1068 enc = &state->newkeys[MODE_OUT]->enc; 1069 mac = &state->newkeys[MODE_OUT]->mac; 1070 comp = &state->newkeys[MODE_OUT]->comp; 1071 /* disable mac for authenticated encryption */ 1072 if ((authlen = cipher_authlen(enc->cipher)) != 0) 1073 mac = NULL; 1074 } 1075 block_size = enc ? enc->block_size : 8; 1076 aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0; 1077 1078 type = (sshbuf_ptr(state->outgoing_packet))[5]; 1079 if (ssh_packet_log_type(type)) 1080 debug3("send packet: type %u", type); 1081#ifdef PACKET_DEBUG 1082 fprintf(stderr, "plain: "); 1083 sshbuf_dump(state->outgoing_packet, stderr); 1084#endif 1085 1086 if (comp && comp->enabled) { 1087 len = sshbuf_len(state->outgoing_packet); 1088 /* skip header, compress only payload */ 1089 if ((r = sshbuf_consume(state->outgoing_packet, 5)) != 0) 1090 goto out; 1091 sshbuf_reset(state->compression_buffer); 1092 if ((r = compress_buffer(ssh, state->outgoing_packet, 1093 state->compression_buffer)) != 0) 1094 goto out; 1095 sshbuf_reset(state->outgoing_packet); 1096 if ((r = sshbuf_put(state->outgoing_packet, 1097 "\0\0\0\0\0", 5)) != 0 || 1098 (r = sshbuf_putb(state->outgoing_packet, 1099 state->compression_buffer)) != 0) 1100 goto out; 1101 DBG(debug("compression: raw %d compressed %zd", len, 1102 sshbuf_len(state->outgoing_packet))); 1103 } 1104 1105 /* sizeof (packet_len + pad_len + payload) */ 1106 len = sshbuf_len(state->outgoing_packet); 1107 1108 /* 1109 * calc size of padding, alloc space, get random data, 1110 * minimum padding is 4 bytes 1111 */ 1112 len -= aadlen; /* packet length is not encrypted for EtM modes */ 1113 padlen = block_size - (len % block_size); 1114 if (padlen < 4) 1115 padlen += block_size; 1116 if (state->extra_pad) { 1117 tmp = state->extra_pad; 1118 state->extra_pad = 1119 ROUNDUP(state->extra_pad, block_size); 1120 /* check if roundup overflowed */ 1121 if (state->extra_pad < tmp) 1122 return SSH_ERR_INVALID_ARGUMENT; 1123 tmp = (len + padlen) % state->extra_pad; 1124 /* Check whether pad calculation below will underflow */ 1125 if (tmp > state->extra_pad) 1126 return SSH_ERR_INVALID_ARGUMENT; 1127 pad = state->extra_pad - tmp; 1128 DBG(debug3_f("adding %d (len %d padlen %d extra_pad %d)", 1129 pad, len, padlen, state->extra_pad)); 1130 tmp = padlen; 1131 padlen += pad; 1132 /* Check whether padlen calculation overflowed */ 1133 if (padlen < tmp) 1134 return SSH_ERR_INVALID_ARGUMENT; /* overflow */ 1135 state->extra_pad = 0; 1136 } 1137 if ((r = sshbuf_reserve(state->outgoing_packet, padlen, &cp)) != 0) 1138 goto out; 1139 if (enc && !cipher_ctx_is_plaintext(state->send_context)) { 1140 /* random padding */ 1141 arc4random_buf(cp, padlen); 1142 } else { 1143 /* clear padding */ 1144 explicit_bzero(cp, padlen); 1145 } 1146 /* sizeof (packet_len + pad_len + payload + padding) */ 1147 len = sshbuf_len(state->outgoing_packet); 1148 cp = sshbuf_mutable_ptr(state->outgoing_packet); 1149 if (cp == NULL) { 1150 r = SSH_ERR_INTERNAL_ERROR; 1151 goto out; 1152 } 1153 /* packet_length includes payload, padding and padding length field */ 1154 POKE_U32(cp, len - 4); 1155 cp[4] = padlen; 1156 DBG(debug("send: len %d (includes padlen %d, aadlen %d)", 1157 len, padlen, aadlen)); 1158 1159 /* compute MAC over seqnr and packet(length fields, payload, padding) */ 1160 if (mac && mac->enabled && !mac->etm) { 1161 if ((r = mac_compute(mac, state->p_send.seqnr, 1162 sshbuf_ptr(state->outgoing_packet), len, 1163 macbuf, sizeof(macbuf))) != 0) 1164 goto out; 1165 DBG(debug("done calc MAC out #%d", state->p_send.seqnr)); 1166 } 1167 /* encrypt packet and append to output buffer. */ 1168 if ((r = sshbuf_reserve(state->output, 1169 sshbuf_len(state->outgoing_packet) + authlen, &cp)) != 0) 1170 goto out; 1171 if ((r = cipher_crypt(state->send_context, state->p_send.seqnr, cp, 1172 sshbuf_ptr(state->outgoing_packet), 1173 len - aadlen, aadlen, authlen)) != 0) 1174 goto out; 1175 /* append unencrypted MAC */ 1176 if (mac && mac->enabled) { 1177 if (mac->etm) { 1178 /* EtM: compute mac over aadlen + cipher text */ 1179 if ((r = mac_compute(mac, state->p_send.seqnr, 1180 cp, len, macbuf, sizeof(macbuf))) != 0) 1181 goto out; 1182 DBG(debug("done calc MAC(EtM) out #%d", 1183 state->p_send.seqnr)); 1184 } 1185 if ((r = sshbuf_put(state->output, macbuf, mac->mac_len)) != 0) 1186 goto out; 1187 } 1188#ifdef PACKET_DEBUG 1189 fprintf(stderr, "encrypted: "); 1190 sshbuf_dump(state->output, stderr); 1191#endif 1192 /* increment sequence number for outgoing packets */ 1193 if (++state->p_send.seqnr == 0) 1194 logit("outgoing seqnr wraps around"); 1195 if (++state->p_send.packets == 0) 1196 if (!(ssh->compat & SSH_BUG_NOREKEY)) 1197 return SSH_ERR_NEED_REKEY; 1198 state->p_send.blocks += len / block_size; 1199 state->p_send.bytes += len; 1200 sshbuf_reset(state->outgoing_packet); 1201 1202 if (type == SSH2_MSG_NEWKEYS) 1203 r = ssh_set_newkeys(ssh, MODE_OUT); 1204 else if (type == SSH2_MSG_USERAUTH_SUCCESS && state->server_side) 1205 r = ssh_packet_enable_delayed_compress(ssh); 1206 else 1207 r = 0; 1208 out: 1209 if (r < 0) 1210 return r; 1211 else 1212 return len - 4; 1213} 1214 1215/* returns non-zero if the specified packet type is usec by KEX */ 1216static int 1217ssh_packet_type_is_kex(u_char type) 1218{ 1219 return 1220 type >= SSH2_MSG_TRANSPORT_MIN && 1221 type <= SSH2_MSG_TRANSPORT_MAX && 1222 type != SSH2_MSG_SERVICE_REQUEST && 1223 type != SSH2_MSG_SERVICE_ACCEPT && 1224 type != SSH2_MSG_EXT_INFO; 1225} 1226 1227int 1228ssh_packet_send2(struct ssh *ssh) 1229{ 1230 struct session_state *state = ssh->state; 1231 struct packet *p; 1232 u_char type; 1233 int r, need_rekey; 1234 int packet_length; 1235 1236 if (sshbuf_len(state->outgoing_packet) < 6) 1237 return SSH_ERR_INTERNAL_ERROR; 1238 type = sshbuf_ptr(state->outgoing_packet)[5]; 1239 need_rekey = !ssh_packet_type_is_kex(type) && 1240 ssh_packet_need_rekeying(ssh, sshbuf_len(state->outgoing_packet)); 1241 1242 /* 1243 * During rekeying we can only send key exchange messages. 1244 * Queue everything else. 1245 */ 1246 if ((need_rekey || state->rekeying) && !ssh_packet_type_is_kex(type)) { 1247 if (need_rekey) 1248 debug3_f("rekex triggered"); 1249 debug("enqueue packet: %u", type); 1250 p = calloc(1, sizeof(*p)); 1251 if (p == NULL) 1252 return SSH_ERR_ALLOC_FAIL; 1253 p->type = type; 1254 p->payload = state->outgoing_packet; 1255 TAILQ_INSERT_TAIL(&state->outgoing, p, next); 1256 state->outgoing_packet = sshbuf_new(); 1257 if (state->outgoing_packet == NULL) 1258 return SSH_ERR_ALLOC_FAIL; 1259 if (need_rekey) { 1260 /* 1261 * This packet triggered a rekey, so send the 1262 * KEXINIT now. 1263 * NB. reenters this function via kex_start_rekex(). 1264 */ 1265 return kex_start_rekex(ssh); 1266 } 1267 return 0; 1268 } 1269 1270 /* rekeying starts with sending KEXINIT */ 1271 if (type == SSH2_MSG_KEXINIT) 1272 state->rekeying = 1; 1273 1274 if ((r = ssh_packet_send2_wrapped(ssh)) < 0) 1275 return r; 1276 1277 packet_length = r; 1278 1279 /* after a NEWKEYS message we can send the complete queue */ 1280 if (type == SSH2_MSG_NEWKEYS) { 1281 state->rekeying = 0; 1282 state->rekey_time = monotime(); 1283 while ((p = TAILQ_FIRST(&state->outgoing))) { 1284 type = p->type; 1285 /* 1286 * If this packet triggers a rekex, then skip the 1287 * remaining packets in the queue for now. 1288 * NB. re-enters this function via kex_start_rekex. 1289 */ 1290 if (ssh_packet_need_rekeying(ssh, 1291 sshbuf_len(p->payload))) { 1292 debug3_f("queued packet triggered rekex"); 1293 return kex_start_rekex(ssh); 1294 } 1295 debug("dequeue packet: %u", type); 1296 sshbuf_free(state->outgoing_packet); 1297 state->outgoing_packet = p->payload; 1298 TAILQ_REMOVE(&state->outgoing, p, next); 1299 memset(p, 0, sizeof(*p)); 1300 free(p); 1301 if ((r = ssh_packet_send2_wrapped(ssh)) < 0) 1302 return r; 1303 packet_length += r; 1304 } 1305 } 1306 return packet_length; 1307} 1308 1309/* 1310 * Waits until a packet has been received, and returns its type. Note that 1311 * no other data is processed until this returns, so this function should not 1312 * be used during the interactive session. 1313 */ 1314 1315int 1316ssh_packet_read_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1317{ 1318 struct session_state *state = ssh->state; 1319 int len, r, ms_remain = 0; 1320 struct pollfd pfd; 1321 char buf[8192]; 1322 struct timeval start; 1323 struct timespec timespec, *timespecp = NULL; 1324 1325 DBG(debug("packet_read()")); 1326 1327 /* 1328 * Since we are blocking, ensure that all written packets have 1329 * been sent. 1330 */ 1331 if ((r = ssh_packet_write_wait(ssh)) < 0) 1332 goto out; 1333 1334 /* Stay in the loop until we have received a complete packet. */ 1335 for (;;) { 1336 /* Try to read a packet from the buffer. */ 1337 r = ssh_packet_read_poll_seqnr(ssh, typep, seqnr_p); 1338 if (r != 0) 1339 break; 1340 /* If we got a packet, return it. */ 1341 if (*typep != SSH_MSG_NONE) 1342 break; 1343 /* 1344 * Otherwise, wait for some data to arrive, add it to the 1345 * buffer, and try again. 1346 */ 1347 pfd.fd = state->connection_in; 1348 pfd.events = POLLIN; 1349 1350 if (state->packet_timeout_ms > 0) { 1351 ms_remain = state->packet_timeout_ms; 1352 timespecp = ×pec; 1353 } 1354 /* Wait for some data to arrive. */ 1355 for (;;) { 1356 if (state->packet_timeout_ms > 0) { 1357 ms_to_timespec(×pec, ms_remain); 1358 monotime_tv(&start); 1359 } 1360 if ((r = ppoll(&pfd, 1, timespecp, NULL)) >= 0) 1361 break; 1362 if (errno != EAGAIN && errno != EINTR) { 1363 r = SSH_ERR_SYSTEM_ERROR; 1364 goto out; 1365 } 1366 if (state->packet_timeout_ms <= 0) 1367 continue; 1368 ms_subtract_diff(&start, &ms_remain); 1369 if (ms_remain <= 0) { 1370 r = 0; 1371 break; 1372 } 1373 } 1374 if (r == 0) { 1375 r = SSH_ERR_CONN_TIMEOUT; 1376 goto out; 1377 } 1378 /* Read data from the socket. */ 1379 len = read(state->connection_in, buf, sizeof(buf)); 1380 if (len == 0) { 1381 r = SSH_ERR_CONN_CLOSED; 1382 goto out; 1383 } 1384 if (len == -1) { 1385 r = SSH_ERR_SYSTEM_ERROR; 1386 goto out; 1387 } 1388 1389 /* Append it to the buffer. */ 1390 if ((r = ssh_packet_process_incoming(ssh, buf, len)) != 0) 1391 goto out; 1392 } 1393 out: 1394 return r; 1395} 1396 1397int 1398ssh_packet_read(struct ssh *ssh) 1399{ 1400 u_char type; 1401 int r; 1402 1403 if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0) 1404 fatal_fr(r, "read"); 1405 return type; 1406} 1407 1408/* 1409 * Waits until a packet has been received, verifies that its type matches 1410 * that given, and gives a fatal error and exits if there is a mismatch. 1411 */ 1412 1413int 1414ssh_packet_read_expect(struct ssh *ssh, u_int expected_type) 1415{ 1416 int r; 1417 u_char type; 1418 1419 if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0) 1420 return r; 1421 if (type != expected_type) { 1422 if ((r = sshpkt_disconnect(ssh, 1423 "Protocol error: expected packet type %d, got %d", 1424 expected_type, type)) != 0) 1425 return r; 1426 return SSH_ERR_PROTOCOL_ERROR; 1427 } 1428 return 0; 1429} 1430 1431static int 1432ssh_packet_read_poll2_mux(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1433{ 1434 struct session_state *state = ssh->state; 1435 const u_char *cp; 1436 size_t need; 1437 int r; 1438 1439 if (ssh->kex) 1440 return SSH_ERR_INTERNAL_ERROR; 1441 *typep = SSH_MSG_NONE; 1442 cp = sshbuf_ptr(state->input); 1443 if (state->packlen == 0) { 1444 if (sshbuf_len(state->input) < 4 + 1) 1445 return 0; /* packet is incomplete */ 1446 state->packlen = PEEK_U32(cp); 1447 if (state->packlen < 4 + 1 || 1448 state->packlen > PACKET_MAX_SIZE) 1449 return SSH_ERR_MESSAGE_INCOMPLETE; 1450 } 1451 need = state->packlen + 4; 1452 if (sshbuf_len(state->input) < need) 1453 return 0; /* packet is incomplete */ 1454 sshbuf_reset(state->incoming_packet); 1455 if ((r = sshbuf_put(state->incoming_packet, cp + 4, 1456 state->packlen)) != 0 || 1457 (r = sshbuf_consume(state->input, need)) != 0 || 1458 (r = sshbuf_get_u8(state->incoming_packet, NULL)) != 0 || 1459 (r = sshbuf_get_u8(state->incoming_packet, typep)) != 0) 1460 return r; 1461 if (ssh_packet_log_type(*typep)) 1462 debug3_f("type %u", *typep); 1463 /* sshbuf_dump(state->incoming_packet, stderr); */ 1464 /* reset for next packet */ 1465 state->packlen = 0; 1466 return r; 1467} 1468 1469int 1470ssh_packet_read_poll2(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1471{ 1472 struct session_state *state = ssh->state; 1473 u_int padlen, need; 1474 u_char *cp; 1475 u_int maclen, aadlen = 0, authlen = 0, block_size; 1476 struct sshenc *enc = NULL; 1477 struct sshmac *mac = NULL; 1478 struct sshcomp *comp = NULL; 1479 int r; 1480 1481 if (state->mux) 1482 return ssh_packet_read_poll2_mux(ssh, typep, seqnr_p); 1483 1484 *typep = SSH_MSG_NONE; 1485 1486 if (state->packet_discard) 1487 return 0; 1488 1489 if (state->newkeys[MODE_IN] != NULL) { 1490 enc = &state->newkeys[MODE_IN]->enc; 1491 mac = &state->newkeys[MODE_IN]->mac; 1492 comp = &state->newkeys[MODE_IN]->comp; 1493 /* disable mac for authenticated encryption */ 1494 if ((authlen = cipher_authlen(enc->cipher)) != 0) 1495 mac = NULL; 1496 } 1497 maclen = mac && mac->enabled ? mac->mac_len : 0; 1498 block_size = enc ? enc->block_size : 8; 1499 aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0; 1500 1501 if (aadlen && state->packlen == 0) { 1502 if (cipher_get_length(state->receive_context, 1503 &state->packlen, state->p_read.seqnr, 1504 sshbuf_ptr(state->input), sshbuf_len(state->input)) != 0) 1505 return 0; 1506 if (state->packlen < 1 + 4 || 1507 state->packlen > PACKET_MAX_SIZE) { 1508#ifdef PACKET_DEBUG 1509 sshbuf_dump(state->input, stderr); 1510#endif 1511 logit("Bad packet length %u.", state->packlen); 1512 if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0) 1513 return r; 1514 return SSH_ERR_CONN_CORRUPT; 1515 } 1516 sshbuf_reset(state->incoming_packet); 1517 } else if (state->packlen == 0) { 1518 /* 1519 * check if input size is less than the cipher block size, 1520 * decrypt first block and extract length of incoming packet 1521 */ 1522 if (sshbuf_len(state->input) < block_size) 1523 return 0; 1524 sshbuf_reset(state->incoming_packet); 1525 if ((r = sshbuf_reserve(state->incoming_packet, block_size, 1526 &cp)) != 0) 1527 goto out; 1528 if ((r = cipher_crypt(state->receive_context, 1529 state->p_send.seqnr, cp, sshbuf_ptr(state->input), 1530 block_size, 0, 0)) != 0) 1531 goto out; 1532 state->packlen = PEEK_U32(sshbuf_ptr(state->incoming_packet)); 1533 if (state->packlen < 1 + 4 || 1534 state->packlen > PACKET_MAX_SIZE) { 1535#ifdef PACKET_DEBUG 1536 fprintf(stderr, "input: \n"); 1537 sshbuf_dump(state->input, stderr); 1538 fprintf(stderr, "incoming_packet: \n"); 1539 sshbuf_dump(state->incoming_packet, stderr); 1540#endif 1541 logit("Bad packet length %u.", state->packlen); 1542 return ssh_packet_start_discard(ssh, enc, mac, 0, 1543 PACKET_MAX_SIZE); 1544 } 1545 if ((r = sshbuf_consume(state->input, block_size)) != 0) 1546 goto out; 1547 } 1548 DBG(debug("input: packet len %u", state->packlen+4)); 1549 1550 if (aadlen) { 1551 /* only the payload is encrypted */ 1552 need = state->packlen; 1553 } else { 1554 /* 1555 * the payload size and the payload are encrypted, but we 1556 * have a partial packet of block_size bytes 1557 */ 1558 need = 4 + state->packlen - block_size; 1559 } 1560 DBG(debug("partial packet: block %d, need %d, maclen %d, authlen %d," 1561 " aadlen %d", block_size, need, maclen, authlen, aadlen)); 1562 if (need % block_size != 0) { 1563 logit("padding error: need %d block %d mod %d", 1564 need, block_size, need % block_size); 1565 return ssh_packet_start_discard(ssh, enc, mac, 0, 1566 PACKET_MAX_SIZE - block_size); 1567 } 1568 /* 1569 * check if the entire packet has been received and 1570 * decrypt into incoming_packet: 1571 * 'aadlen' bytes are unencrypted, but authenticated. 1572 * 'need' bytes are encrypted, followed by either 1573 * 'authlen' bytes of authentication tag or 1574 * 'maclen' bytes of message authentication code. 1575 */ 1576 if (sshbuf_len(state->input) < aadlen + need + authlen + maclen) 1577 return 0; /* packet is incomplete */ 1578#ifdef PACKET_DEBUG 1579 fprintf(stderr, "read_poll enc/full: "); 1580 sshbuf_dump(state->input, stderr); 1581#endif 1582 /* EtM: check mac over encrypted input */ 1583 if (mac && mac->enabled && mac->etm) { 1584 if ((r = mac_check(mac, state->p_read.seqnr, 1585 sshbuf_ptr(state->input), aadlen + need, 1586 sshbuf_ptr(state->input) + aadlen + need + authlen, 1587 maclen)) != 0) { 1588 if (r == SSH_ERR_MAC_INVALID) 1589 logit("Corrupted MAC on input."); 1590 goto out; 1591 } 1592 } 1593 if ((r = sshbuf_reserve(state->incoming_packet, aadlen + need, 1594 &cp)) != 0) 1595 goto out; 1596 if ((r = cipher_crypt(state->receive_context, state->p_read.seqnr, cp, 1597 sshbuf_ptr(state->input), need, aadlen, authlen)) != 0) 1598 goto out; 1599 if ((r = sshbuf_consume(state->input, aadlen + need + authlen)) != 0) 1600 goto out; 1601 if (mac && mac->enabled) { 1602 /* Not EtM: check MAC over cleartext */ 1603 if (!mac->etm && (r = mac_check(mac, state->p_read.seqnr, 1604 sshbuf_ptr(state->incoming_packet), 1605 sshbuf_len(state->incoming_packet), 1606 sshbuf_ptr(state->input), maclen)) != 0) { 1607 if (r != SSH_ERR_MAC_INVALID) 1608 goto out; 1609 logit("Corrupted MAC on input."); 1610 if (need + block_size > PACKET_MAX_SIZE) 1611 return SSH_ERR_INTERNAL_ERROR; 1612 return ssh_packet_start_discard(ssh, enc, mac, 1613 sshbuf_len(state->incoming_packet), 1614 PACKET_MAX_SIZE - need - block_size); 1615 } 1616 /* Remove MAC from input buffer */ 1617 DBG(debug("MAC #%d ok", state->p_read.seqnr)); 1618 if ((r = sshbuf_consume(state->input, mac->mac_len)) != 0) 1619 goto out; 1620 } 1621 if (seqnr_p != NULL) 1622 *seqnr_p = state->p_read.seqnr; 1623 if (++state->p_read.seqnr == 0) 1624 logit("incoming seqnr wraps around"); 1625 if (++state->p_read.packets == 0) 1626 if (!(ssh->compat & SSH_BUG_NOREKEY)) 1627 return SSH_ERR_NEED_REKEY; 1628 state->p_read.blocks += (state->packlen + 4) / block_size; 1629 state->p_read.bytes += state->packlen + 4; 1630 1631 /* get padlen */ 1632 padlen = sshbuf_ptr(state->incoming_packet)[4]; 1633 DBG(debug("input: padlen %d", padlen)); 1634 if (padlen < 4) { 1635 if ((r = sshpkt_disconnect(ssh, 1636 "Corrupted padlen %d on input.", padlen)) != 0 || 1637 (r = ssh_packet_write_wait(ssh)) < 0) 1638 return r; 1639 return SSH_ERR_CONN_CORRUPT; 1640 } 1641 1642 /* skip packet size + padlen, discard padding */ 1643 if ((r = sshbuf_consume(state->incoming_packet, 4 + 1)) != 0 || 1644 ((r = sshbuf_consume_end(state->incoming_packet, padlen)) != 0)) 1645 goto out; 1646 1647 DBG(debug("input: len before de-compress %zd", 1648 sshbuf_len(state->incoming_packet))); 1649 if (comp && comp->enabled) { 1650 sshbuf_reset(state->compression_buffer); 1651 if ((r = uncompress_buffer(ssh, state->incoming_packet, 1652 state->compression_buffer)) != 0) 1653 goto out; 1654 sshbuf_reset(state->incoming_packet); 1655 if ((r = sshbuf_putb(state->incoming_packet, 1656 state->compression_buffer)) != 0) 1657 goto out; 1658 DBG(debug("input: len after de-compress %zd", 1659 sshbuf_len(state->incoming_packet))); 1660 } 1661 /* 1662 * get packet type, implies consume. 1663 * return length of payload (without type field) 1664 */ 1665 if ((r = sshbuf_get_u8(state->incoming_packet, typep)) != 0) 1666 goto out; 1667 if (ssh_packet_log_type(*typep)) 1668 debug3("receive packet: type %u", *typep); 1669 if (*typep < SSH2_MSG_MIN || *typep >= SSH2_MSG_LOCAL_MIN) { 1670 if ((r = sshpkt_disconnect(ssh, 1671 "Invalid ssh2 packet type: %d", *typep)) != 0 || 1672 (r = ssh_packet_write_wait(ssh)) < 0) 1673 return r; 1674 return SSH_ERR_PROTOCOL_ERROR; 1675 } 1676 if (state->hook_in != NULL && 1677 (r = state->hook_in(ssh, state->incoming_packet, typep, 1678 state->hook_in_ctx)) != 0) 1679 return r; 1680 if (*typep == SSH2_MSG_USERAUTH_SUCCESS && !state->server_side) 1681 r = ssh_packet_enable_delayed_compress(ssh); 1682 else 1683 r = 0; 1684#ifdef PACKET_DEBUG 1685 fprintf(stderr, "read/plain[%d]:\r\n", *typep); 1686 sshbuf_dump(state->incoming_packet, stderr); 1687#endif 1688 /* reset for next packet */ 1689 state->packlen = 0; 1690 1691 if ((r = ssh_packet_check_rekey(ssh)) != 0) 1692 return r; 1693 out: 1694 return r; 1695} 1696 1697int 1698ssh_packet_read_poll_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1699{ 1700 struct session_state *state = ssh->state; 1701 u_int reason, seqnr; 1702 int r; 1703 u_char *msg; 1704 1705 for (;;) { 1706 msg = NULL; 1707 r = ssh_packet_read_poll2(ssh, typep, seqnr_p); 1708 if (r != 0) 1709 return r; 1710 if (*typep) { 1711 state->keep_alive_timeouts = 0; 1712 DBG(debug("received packet type %d", *typep)); 1713 } 1714 switch (*typep) { 1715 case SSH2_MSG_IGNORE: 1716 debug3("Received SSH2_MSG_IGNORE"); 1717 break; 1718 case SSH2_MSG_DEBUG: 1719 if ((r = sshpkt_get_u8(ssh, NULL)) != 0 || 1720 (r = sshpkt_get_string(ssh, &msg, NULL)) != 0 || 1721 (r = sshpkt_get_string(ssh, NULL, NULL)) != 0) { 1722 free(msg); 1723 return r; 1724 } 1725 debug("Remote: %.900s", msg); 1726 free(msg); 1727 break; 1728 case SSH2_MSG_DISCONNECT: 1729 if ((r = sshpkt_get_u32(ssh, &reason)) != 0 || 1730 (r = sshpkt_get_string(ssh, &msg, NULL)) != 0) 1731 return r; 1732 /* Ignore normal client exit notifications */ 1733 do_log2(ssh->state->server_side && 1734 reason == SSH2_DISCONNECT_BY_APPLICATION ? 1735 SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_ERROR, 1736 "Received disconnect from %s port %d:" 1737 "%u: %.400s", ssh_remote_ipaddr(ssh), 1738 ssh_remote_port(ssh), reason, msg); 1739 free(msg); 1740 return SSH_ERR_DISCONNECTED; 1741 case SSH2_MSG_UNIMPLEMENTED: 1742 if ((r = sshpkt_get_u32(ssh, &seqnr)) != 0) 1743 return r; 1744 debug("Received SSH2_MSG_UNIMPLEMENTED for %u", 1745 seqnr); 1746 break; 1747 default: 1748 return 0; 1749 } 1750 } 1751} 1752 1753/* 1754 * Buffers the supplied input data. This is intended to be used together 1755 * with packet_read_poll(). 1756 */ 1757int 1758ssh_packet_process_incoming(struct ssh *ssh, const char *buf, u_int len) 1759{ 1760 struct session_state *state = ssh->state; 1761 int r; 1762 1763 if (state->packet_discard) { 1764 state->keep_alive_timeouts = 0; /* ?? */ 1765 if (len >= state->packet_discard) { 1766 if ((r = ssh_packet_stop_discard(ssh)) != 0) 1767 return r; 1768 } 1769 state->packet_discard -= len; 1770 return 0; 1771 } 1772 if ((r = sshbuf_put(state->input, buf, len)) != 0) 1773 return r; 1774 1775 return 0; 1776} 1777 1778/* Reads and buffers data from the specified fd */ 1779int 1780ssh_packet_process_read(struct ssh *ssh, int fd) 1781{ 1782 struct session_state *state = ssh->state; 1783 int r; 1784 size_t rlen; 1785 1786 if ((r = sshbuf_read(fd, state->input, PACKET_MAX_SIZE, &rlen)) != 0) 1787 return r; 1788 1789 if (state->packet_discard) { 1790 if ((r = sshbuf_consume_end(state->input, rlen)) != 0) 1791 return r; 1792 state->keep_alive_timeouts = 0; /* ?? */ 1793 if (rlen >= state->packet_discard) { 1794 if ((r = ssh_packet_stop_discard(ssh)) != 0) 1795 return r; 1796 } 1797 state->packet_discard -= rlen; 1798 return 0; 1799 } 1800 return 0; 1801} 1802 1803int 1804ssh_packet_remaining(struct ssh *ssh) 1805{ 1806 return sshbuf_len(ssh->state->incoming_packet); 1807} 1808 1809/* 1810 * Sends a diagnostic message from the server to the client. This message 1811 * can be sent at any time (but not while constructing another message). The 1812 * message is printed immediately, but only if the client is being executed 1813 * in verbose mode. These messages are primarily intended to ease debugging 1814 * authentication problems. The length of the formatted message must not 1815 * exceed 1024 bytes. This will automatically call ssh_packet_write_wait. 1816 */ 1817void __attribute__((__format__ (__printf__, 2, 3))) 1818ssh_packet_send_debug(struct ssh *ssh, const char *fmt,...) 1819{ 1820 char buf[1024]; 1821 va_list args; 1822 int r; 1823 1824 if ((ssh->compat & SSH_BUG_DEBUG)) 1825 return; 1826 1827 va_start(args, fmt); 1828 vsnprintf(buf, sizeof(buf), fmt, args); 1829 va_end(args); 1830 1831 debug3("sending debug message: %s", buf); 1832 1833 if ((r = sshpkt_start(ssh, SSH2_MSG_DEBUG)) != 0 || 1834 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* always display */ 1835 (r = sshpkt_put_cstring(ssh, buf)) != 0 || 1836 (r = sshpkt_put_cstring(ssh, "")) != 0 || 1837 (r = sshpkt_send(ssh)) != 0 || 1838 (r = ssh_packet_write_wait(ssh)) < 0) 1839 fatal_fr(r, "send DEBUG"); 1840} 1841 1842void 1843sshpkt_fmt_connection_id(struct ssh *ssh, char *s, size_t l) 1844{ 1845 snprintf(s, l, "%.200s%s%s port %d", 1846 ssh->log_preamble ? ssh->log_preamble : "", 1847 ssh->log_preamble ? " " : "", 1848 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 1849} 1850 1851/* 1852 * Pretty-print connection-terminating errors and exit. 1853 */ 1854static void __attribute__((__format__ (__printf__, 3, 0))) 1855__attribute__((__noreturn__)) 1856sshpkt_vfatal(struct ssh *ssh, int r, const char *fmt, va_list ap) 1857{ 1858 char *tag = NULL, remote_id[512]; 1859 int oerrno = errno; 1860 1861 sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id)); 1862 1863 switch (r) { 1864 case SSH_ERR_CONN_CLOSED: 1865 ssh_packet_clear_keys(ssh); 1866 logdie("Connection closed by %s", remote_id); 1867 case SSH_ERR_CONN_TIMEOUT: 1868 ssh_packet_clear_keys(ssh); 1869 logdie("Connection %s %s timed out", 1870 ssh->state->server_side ? "from" : "to", remote_id); 1871 case SSH_ERR_DISCONNECTED: 1872 ssh_packet_clear_keys(ssh); 1873 logdie("Disconnected from %s", remote_id); 1874 case SSH_ERR_SYSTEM_ERROR: 1875 if (errno == ECONNRESET) { 1876 ssh_packet_clear_keys(ssh); 1877 logdie("Connection reset by %s", remote_id); 1878 } 1879 /* FALLTHROUGH */ 1880 case SSH_ERR_NO_CIPHER_ALG_MATCH: 1881 case SSH_ERR_NO_MAC_ALG_MATCH: 1882 case SSH_ERR_NO_COMPRESS_ALG_MATCH: 1883 case SSH_ERR_NO_KEX_ALG_MATCH: 1884 case SSH_ERR_NO_HOSTKEY_ALG_MATCH: 1885 if (ssh && ssh->kex && ssh->kex->failed_choice) { 1886 ssh_packet_clear_keys(ssh); 1887 errno = oerrno; 1888 logdie("Unable to negotiate with %s: %s. " 1889 "Their offer: %s", remote_id, ssh_err(r), 1890 ssh->kex->failed_choice); 1891 } 1892 /* FALLTHROUGH */ 1893 default: 1894 if (vasprintf(&tag, fmt, ap) == -1) { 1895 ssh_packet_clear_keys(ssh); 1896 logdie_f("could not allocate failure message"); 1897 } 1898 ssh_packet_clear_keys(ssh); 1899 errno = oerrno; 1900 logdie_r(r, "%s%sConnection %s %s", 1901 tag != NULL ? tag : "", tag != NULL ? ": " : "", 1902 ssh->state->server_side ? "from" : "to", remote_id); 1903 } 1904} 1905 1906void __attribute__((__format__ (__printf__, 3, 4))) 1907__attribute__((__noreturn__)) 1908sshpkt_fatal(struct ssh *ssh, int r, const char *fmt, ...) 1909{ 1910 va_list ap; 1911 1912 va_start(ap, fmt); 1913 sshpkt_vfatal(ssh, r, fmt, ap); 1914 /* NOTREACHED */ 1915 va_end(ap); 1916 logdie_f("should have exited"); 1917} 1918 1919/* 1920 * Logs the error plus constructs and sends a disconnect packet, closes the 1921 * connection, and exits. This function never returns. The error message 1922 * should not contain a newline. The length of the formatted message must 1923 * not exceed 1024 bytes. 1924 */ 1925void 1926ssh_packet_disconnect(struct ssh *ssh, const char *fmt,...) 1927{ 1928 char buf[1024], remote_id[512]; 1929 va_list args; 1930 static int disconnecting = 0; 1931 int r; 1932 1933 if (disconnecting) /* Guard against recursive invocations. */ 1934 fatal("packet_disconnect called recursively."); 1935 disconnecting = 1; 1936 1937 /* 1938 * Format the message. Note that the caller must make sure the 1939 * message is of limited size. 1940 */ 1941 sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id)); 1942 va_start(args, fmt); 1943 vsnprintf(buf, sizeof(buf), fmt, args); 1944 va_end(args); 1945 1946 /* Display the error locally */ 1947 logit("Disconnecting %s: %.100s", remote_id, buf); 1948 1949 /* 1950 * Send the disconnect message to the other side, and wait 1951 * for it to get sent. 1952 */ 1953 if ((r = sshpkt_disconnect(ssh, "%s", buf)) != 0) 1954 sshpkt_fatal(ssh, r, "%s", __func__); 1955 1956 if ((r = ssh_packet_write_wait(ssh)) < 0) 1957 sshpkt_fatal(ssh, r, "%s", __func__); 1958 1959 /* Close the connection. */ 1960 ssh_packet_close(ssh); 1961 cleanup_exit(254); 1962} 1963 1964/* 1965 * Checks if there is any buffered output, and tries to write some of 1966 * the output. 1967 */ 1968int 1969ssh_packet_write_poll(struct ssh *ssh) 1970{ 1971 struct session_state *state = ssh->state; 1972 int len = sshbuf_len(state->output); 1973 int r; 1974 1975 if (len > 0) { 1976 len = write(state->connection_out, 1977 sshbuf_ptr(state->output), len); 1978 if (len == -1) { 1979 if (errno == EINTR || errno == EAGAIN) 1980 return 0; 1981 return SSH_ERR_SYSTEM_ERROR; 1982 } 1983 if (len == 0) 1984 return SSH_ERR_CONN_CLOSED; 1985 if ((r = sshbuf_consume(state->output, len)) < 0) 1986 return r; 1987 } 1988 return len; 1989} 1990 1991/* 1992 * Calls packet_write_poll repeatedly until all pending output data has been 1993 * written. 1994 */ 1995int 1996ssh_packet_write_wait(struct ssh *ssh) 1997{ 1998 int ret, r, ms_remain = 0; 1999 u_int bytes_sent = 0; 2000 struct timeval start; 2001 struct timespec timespec, *timespecp = NULL; 2002 struct session_state *state = ssh->state; 2003 struct pollfd pfd; 2004 2005 if ((r = ssh_packet_write_poll(ssh)) < 0) 2006 return r; 2007 bytes_sent += r; 2008 2009 while (ssh_packet_have_data_to_write(ssh)) { 2010 pfd.fd = state->connection_out; 2011 pfd.events = POLLOUT; 2012 2013 if (state->packet_timeout_ms > 0) { 2014 ms_remain = state->packet_timeout_ms; 2015 timespecp = ×pec; 2016 } 2017 for (;;) { 2018 if (state->packet_timeout_ms > 0) { 2019 ms_to_timespec(×pec, ms_remain); 2020 monotime_tv(&start); 2021 } 2022 if ((ret = ppoll(&pfd, 1, timespecp, NULL)) >= 0) 2023 break; 2024 if (errno != EAGAIN && errno != EINTR) 2025 break; 2026 if (state->packet_timeout_ms <= 0) 2027 continue; 2028 ms_subtract_diff(&start, &ms_remain); 2029 if (ms_remain <= 0) { 2030 ret = 0; 2031 break; 2032 } 2033 } 2034 if (ret == 0) 2035 return SSH_ERR_CONN_TIMEOUT; 2036 if ((r = ssh_packet_write_poll(ssh)) < 0) 2037 return r; 2038 bytes_sent += r; 2039 } 2040 return bytes_sent; 2041} 2042 2043/* Returns true if there is buffered data to write to the connection. */ 2044 2045int 2046ssh_packet_have_data_to_write(struct ssh *ssh) 2047{ 2048 return sshbuf_len(ssh->state->output) != 0; 2049} 2050 2051/* Returns true if there is not too much data to write to the connection. */ 2052 2053int 2054ssh_packet_not_very_much_data_to_write(struct ssh *ssh) 2055{ 2056 if (ssh->state->interactive_mode) 2057 return sshbuf_len(ssh->state->output) < 16384; 2058 else 2059 return sshbuf_len(ssh->state->output) < 128 * 1024; 2060} 2061 2062void 2063ssh_packet_set_tos(struct ssh *ssh, int tos) 2064{ 2065 if (!ssh_packet_connection_is_on_socket(ssh) || tos == INT_MAX) 2066 return; 2067 set_sock_tos(ssh->state->connection_in, tos); 2068} 2069 2070/* Informs that the current session is interactive. Sets IP flags for that. */ 2071 2072void 2073ssh_packet_set_interactive(struct ssh *ssh, int interactive, int qos_interactive, int qos_bulk) 2074{ 2075 struct session_state *state = ssh->state; 2076 2077 if (state->set_interactive_called) 2078 return; 2079 state->set_interactive_called = 1; 2080 2081 /* Record that we are in interactive mode. */ 2082 state->interactive_mode = interactive; 2083 2084 /* Only set socket options if using a socket. */ 2085 if (!ssh_packet_connection_is_on_socket(ssh)) 2086 return; 2087 set_nodelay(state->connection_in); 2088 ssh_packet_set_tos(ssh, interactive ? qos_interactive : qos_bulk); 2089} 2090 2091/* Returns true if the current connection is interactive. */ 2092 2093int 2094ssh_packet_is_interactive(struct ssh *ssh) 2095{ 2096 return ssh->state->interactive_mode; 2097} 2098 2099int 2100ssh_packet_set_maxsize(struct ssh *ssh, u_int s) 2101{ 2102 struct session_state *state = ssh->state; 2103 2104 if (state->set_maxsize_called) { 2105 logit_f("called twice: old %d new %d", 2106 state->max_packet_size, s); 2107 return -1; 2108 } 2109 if (s < 4 * 1024 || s > 1024 * 1024) { 2110 logit_f("bad size %d", s); 2111 return -1; 2112 } 2113 state->set_maxsize_called = 1; 2114 debug_f("setting to %d", s); 2115 state->max_packet_size = s; 2116 return s; 2117} 2118 2119int 2120ssh_packet_inc_alive_timeouts(struct ssh *ssh) 2121{ 2122 return ++ssh->state->keep_alive_timeouts; 2123} 2124 2125void 2126ssh_packet_set_alive_timeouts(struct ssh *ssh, int ka) 2127{ 2128 ssh->state->keep_alive_timeouts = ka; 2129} 2130 2131u_int 2132ssh_packet_get_maxsize(struct ssh *ssh) 2133{ 2134 return ssh->state->max_packet_size; 2135} 2136 2137void 2138ssh_packet_set_rekey_limits(struct ssh *ssh, u_int64_t bytes, u_int32_t seconds) 2139{ 2140 debug3("rekey after %llu bytes, %u seconds", (unsigned long long)bytes, 2141 (unsigned int)seconds); 2142 ssh->state->rekey_limit = bytes; 2143 ssh->state->rekey_interval = seconds; 2144} 2145 2146time_t 2147ssh_packet_get_rekey_timeout(struct ssh *ssh) 2148{ 2149 time_t seconds; 2150 2151 seconds = ssh->state->rekey_time + ssh->state->rekey_interval - 2152 monotime(); 2153 return (seconds <= 0 ? 1 : seconds); 2154} 2155 2156void 2157ssh_packet_set_server(struct ssh *ssh) 2158{ 2159 ssh->state->server_side = 1; 2160 ssh->kex->server = 1; /* XXX unify? */ 2161} 2162 2163void 2164ssh_packet_set_authenticated(struct ssh *ssh) 2165{ 2166 ssh->state->after_authentication = 1; 2167} 2168 2169void * 2170ssh_packet_get_input(struct ssh *ssh) 2171{ 2172 return (void *)ssh->state->input; 2173} 2174 2175void * 2176ssh_packet_get_output(struct ssh *ssh) 2177{ 2178 return (void *)ssh->state->output; 2179} 2180 2181/* Reset after_authentication and reset compression in post-auth privsep */ 2182static int 2183ssh_packet_set_postauth(struct ssh *ssh) 2184{ 2185 int r; 2186 2187 debug_f("called"); 2188 /* This was set in net child, but is not visible in user child */ 2189 ssh->state->after_authentication = 1; 2190 ssh->state->rekeying = 0; 2191 if ((r = ssh_packet_enable_delayed_compress(ssh)) != 0) 2192 return r; 2193 return 0; 2194} 2195 2196/* Packet state (de-)serialization for privsep */ 2197 2198/* turn kex into a blob for packet state serialization */ 2199static int 2200kex_to_blob(struct sshbuf *m, struct kex *kex) 2201{ 2202 int r; 2203 2204 if ((r = sshbuf_put_u32(m, kex->we_need)) != 0 || 2205 (r = sshbuf_put_cstring(m, kex->hostkey_alg)) != 0 || 2206 (r = sshbuf_put_u32(m, kex->hostkey_type)) != 0 || 2207 (r = sshbuf_put_u32(m, kex->hostkey_nid)) != 0 || 2208 (r = sshbuf_put_u32(m, kex->kex_type)) != 0 || 2209 (r = sshbuf_put_stringb(m, kex->my)) != 0 || 2210 (r = sshbuf_put_stringb(m, kex->peer)) != 0 || 2211 (r = sshbuf_put_stringb(m, kex->client_version)) != 0 || 2212 (r = sshbuf_put_stringb(m, kex->server_version)) != 0 || 2213 (r = sshbuf_put_stringb(m, kex->session_id)) != 0 || 2214 (r = sshbuf_put_u32(m, kex->flags)) != 0) 2215 return r; 2216 return 0; 2217} 2218 2219/* turn key exchange results into a blob for packet state serialization */ 2220static int 2221newkeys_to_blob(struct sshbuf *m, struct ssh *ssh, int mode) 2222{ 2223 struct sshbuf *b; 2224 struct sshcipher_ctx *cc; 2225 struct sshcomp *comp; 2226 struct sshenc *enc; 2227 struct sshmac *mac; 2228 struct newkeys *newkey; 2229 int r; 2230 2231 if ((newkey = ssh->state->newkeys[mode]) == NULL) 2232 return SSH_ERR_INTERNAL_ERROR; 2233 enc = &newkey->enc; 2234 mac = &newkey->mac; 2235 comp = &newkey->comp; 2236 cc = (mode == MODE_OUT) ? ssh->state->send_context : 2237 ssh->state->receive_context; 2238 if ((r = cipher_get_keyiv(cc, enc->iv, enc->iv_len)) != 0) 2239 return r; 2240 if ((b = sshbuf_new()) == NULL) 2241 return SSH_ERR_ALLOC_FAIL; 2242 if ((r = sshbuf_put_cstring(b, enc->name)) != 0 || 2243 (r = sshbuf_put_u32(b, enc->enabled)) != 0 || 2244 (r = sshbuf_put_u32(b, enc->block_size)) != 0 || 2245 (r = sshbuf_put_string(b, enc->key, enc->key_len)) != 0 || 2246 (r = sshbuf_put_string(b, enc->iv, enc->iv_len)) != 0) 2247 goto out; 2248 if (cipher_authlen(enc->cipher) == 0) { 2249 if ((r = sshbuf_put_cstring(b, mac->name)) != 0 || 2250 (r = sshbuf_put_u32(b, mac->enabled)) != 0 || 2251 (r = sshbuf_put_string(b, mac->key, mac->key_len)) != 0) 2252 goto out; 2253 } 2254 if ((r = sshbuf_put_u32(b, comp->type)) != 0 || 2255 (r = sshbuf_put_cstring(b, comp->name)) != 0) 2256 goto out; 2257 r = sshbuf_put_stringb(m, b); 2258 out: 2259 sshbuf_free(b); 2260 return r; 2261} 2262 2263/* serialize packet state into a blob */ 2264int 2265ssh_packet_get_state(struct ssh *ssh, struct sshbuf *m) 2266{ 2267 struct session_state *state = ssh->state; 2268 int r; 2269 2270 if ((r = kex_to_blob(m, ssh->kex)) != 0 || 2271 (r = newkeys_to_blob(m, ssh, MODE_OUT)) != 0 || 2272 (r = newkeys_to_blob(m, ssh, MODE_IN)) != 0 || 2273 (r = sshbuf_put_u64(m, state->rekey_limit)) != 0 || 2274 (r = sshbuf_put_u32(m, state->rekey_interval)) != 0 || 2275 (r = sshbuf_put_u32(m, state->p_send.seqnr)) != 0 || 2276 (r = sshbuf_put_u64(m, state->p_send.blocks)) != 0 || 2277 (r = sshbuf_put_u32(m, state->p_send.packets)) != 0 || 2278 (r = sshbuf_put_u64(m, state->p_send.bytes)) != 0 || 2279 (r = sshbuf_put_u32(m, state->p_read.seqnr)) != 0 || 2280 (r = sshbuf_put_u64(m, state->p_read.blocks)) != 0 || 2281 (r = sshbuf_put_u32(m, state->p_read.packets)) != 0 || 2282 (r = sshbuf_put_u64(m, state->p_read.bytes)) != 0 || 2283 (r = sshbuf_put_stringb(m, state->input)) != 0 || 2284 (r = sshbuf_put_stringb(m, state->output)) != 0) 2285 return r; 2286 2287 return 0; 2288} 2289 2290/* restore key exchange results from blob for packet state de-serialization */ 2291static int 2292newkeys_from_blob(struct sshbuf *m, struct ssh *ssh, int mode) 2293{ 2294 struct sshbuf *b = NULL; 2295 struct sshcomp *comp; 2296 struct sshenc *enc; 2297 struct sshmac *mac; 2298 struct newkeys *newkey = NULL; 2299 size_t keylen, ivlen, maclen; 2300 int r; 2301 2302 if ((newkey = calloc(1, sizeof(*newkey))) == NULL) { 2303 r = SSH_ERR_ALLOC_FAIL; 2304 goto out; 2305 } 2306 if ((r = sshbuf_froms(m, &b)) != 0) 2307 goto out; 2308#ifdef DEBUG_PK 2309 sshbuf_dump(b, stderr); 2310#endif 2311 enc = &newkey->enc; 2312 mac = &newkey->mac; 2313 comp = &newkey->comp; 2314 2315 if ((r = sshbuf_get_cstring(b, &enc->name, NULL)) != 0 || 2316 (r = sshbuf_get_u32(b, (u_int *)&enc->enabled)) != 0 || 2317 (r = sshbuf_get_u32(b, &enc->block_size)) != 0 || 2318 (r = sshbuf_get_string(b, &enc->key, &keylen)) != 0 || 2319 (r = sshbuf_get_string(b, &enc->iv, &ivlen)) != 0) 2320 goto out; 2321 if ((enc->cipher = cipher_by_name(enc->name)) == NULL) { 2322 r = SSH_ERR_INVALID_FORMAT; 2323 goto out; 2324 } 2325 if (cipher_authlen(enc->cipher) == 0) { 2326 if ((r = sshbuf_get_cstring(b, &mac->name, NULL)) != 0) 2327 goto out; 2328 if ((r = mac_setup(mac, mac->name)) != 0) 2329 goto out; 2330 if ((r = sshbuf_get_u32(b, (u_int *)&mac->enabled)) != 0 || 2331 (r = sshbuf_get_string(b, &mac->key, &maclen)) != 0) 2332 goto out; 2333 if (maclen > mac->key_len) { 2334 r = SSH_ERR_INVALID_FORMAT; 2335 goto out; 2336 } 2337 mac->key_len = maclen; 2338 } 2339 if ((r = sshbuf_get_u32(b, &comp->type)) != 0 || 2340 (r = sshbuf_get_cstring(b, &comp->name, NULL)) != 0) 2341 goto out; 2342 if (sshbuf_len(b) != 0) { 2343 r = SSH_ERR_INVALID_FORMAT; 2344 goto out; 2345 } 2346 enc->key_len = keylen; 2347 enc->iv_len = ivlen; 2348 ssh->kex->newkeys[mode] = newkey; 2349 newkey = NULL; 2350 r = 0; 2351 out: 2352 free(newkey); 2353 sshbuf_free(b); 2354 return r; 2355} 2356 2357/* restore kex from blob for packet state de-serialization */ 2358static int 2359kex_from_blob(struct sshbuf *m, struct kex **kexp) 2360{ 2361 struct kex *kex; 2362 int r; 2363 2364 if ((kex = kex_new()) == NULL) 2365 return SSH_ERR_ALLOC_FAIL; 2366 if ((r = sshbuf_get_u32(m, &kex->we_need)) != 0 || 2367 (r = sshbuf_get_cstring(m, &kex->hostkey_alg, NULL)) != 0 || 2368 (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_type)) != 0 || 2369 (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_nid)) != 0 || 2370 (r = sshbuf_get_u32(m, &kex->kex_type)) != 0 || 2371 (r = sshbuf_get_stringb(m, kex->my)) != 0 || 2372 (r = sshbuf_get_stringb(m, kex->peer)) != 0 || 2373 (r = sshbuf_get_stringb(m, kex->client_version)) != 0 || 2374 (r = sshbuf_get_stringb(m, kex->server_version)) != 0 || 2375 (r = sshbuf_get_stringb(m, kex->session_id)) != 0 || 2376 (r = sshbuf_get_u32(m, &kex->flags)) != 0) 2377 goto out; 2378 kex->server = 1; 2379 kex->done = 1; 2380 r = 0; 2381 out: 2382 if (r != 0 || kexp == NULL) { 2383 kex_free(kex); 2384 if (kexp != NULL) 2385 *kexp = NULL; 2386 } else { 2387 kex_free(*kexp); 2388 *kexp = kex; 2389 } 2390 return r; 2391} 2392 2393/* 2394 * Restore packet state from content of blob 'm' (de-serialization). 2395 * Note that 'm' will be partially consumed on parsing or any other errors. 2396 */ 2397int 2398ssh_packet_set_state(struct ssh *ssh, struct sshbuf *m) 2399{ 2400 struct session_state *state = ssh->state; 2401 const u_char *input, *output; 2402 size_t ilen, olen; 2403 int r; 2404 2405 if ((r = kex_from_blob(m, &ssh->kex)) != 0 || 2406 (r = newkeys_from_blob(m, ssh, MODE_OUT)) != 0 || 2407 (r = newkeys_from_blob(m, ssh, MODE_IN)) != 0 || 2408 (r = sshbuf_get_u64(m, &state->rekey_limit)) != 0 || 2409 (r = sshbuf_get_u32(m, &state->rekey_interval)) != 0 || 2410 (r = sshbuf_get_u32(m, &state->p_send.seqnr)) != 0 || 2411 (r = sshbuf_get_u64(m, &state->p_send.blocks)) != 0 || 2412 (r = sshbuf_get_u32(m, &state->p_send.packets)) != 0 || 2413 (r = sshbuf_get_u64(m, &state->p_send.bytes)) != 0 || 2414 (r = sshbuf_get_u32(m, &state->p_read.seqnr)) != 0 || 2415 (r = sshbuf_get_u64(m, &state->p_read.blocks)) != 0 || 2416 (r = sshbuf_get_u32(m, &state->p_read.packets)) != 0 || 2417 (r = sshbuf_get_u64(m, &state->p_read.bytes)) != 0) 2418 return r; 2419 /* 2420 * We set the time here so that in post-auth privsep child we 2421 * count from the completion of the authentication. 2422 */ 2423 state->rekey_time = monotime(); 2424 /* XXX ssh_set_newkeys overrides p_read.packets? XXX */ 2425 if ((r = ssh_set_newkeys(ssh, MODE_IN)) != 0 || 2426 (r = ssh_set_newkeys(ssh, MODE_OUT)) != 0) 2427 return r; 2428 2429 if ((r = ssh_packet_set_postauth(ssh)) != 0) 2430 return r; 2431 2432 sshbuf_reset(state->input); 2433 sshbuf_reset(state->output); 2434 if ((r = sshbuf_get_string_direct(m, &input, &ilen)) != 0 || 2435 (r = sshbuf_get_string_direct(m, &output, &olen)) != 0 || 2436 (r = sshbuf_put(state->input, input, ilen)) != 0 || 2437 (r = sshbuf_put(state->output, output, olen)) != 0) 2438 return r; 2439 2440 if (sshbuf_len(m)) 2441 return SSH_ERR_INVALID_FORMAT; 2442 debug3_f("done"); 2443 return 0; 2444} 2445 2446/* NEW API */ 2447 2448/* put data to the outgoing packet */ 2449 2450int 2451sshpkt_put(struct ssh *ssh, const void *v, size_t len) 2452{ 2453 return sshbuf_put(ssh->state->outgoing_packet, v, len); 2454} 2455 2456int 2457sshpkt_putb(struct ssh *ssh, const struct sshbuf *b) 2458{ 2459 return sshbuf_putb(ssh->state->outgoing_packet, b); 2460} 2461 2462int 2463sshpkt_put_u8(struct ssh *ssh, u_char val) 2464{ 2465 return sshbuf_put_u8(ssh->state->outgoing_packet, val); 2466} 2467 2468int 2469sshpkt_put_u32(struct ssh *ssh, u_int32_t val) 2470{ 2471 return sshbuf_put_u32(ssh->state->outgoing_packet, val); 2472} 2473 2474int 2475sshpkt_put_u64(struct ssh *ssh, u_int64_t val) 2476{ 2477 return sshbuf_put_u64(ssh->state->outgoing_packet, val); 2478} 2479 2480int 2481sshpkt_put_string(struct ssh *ssh, const void *v, size_t len) 2482{ 2483 return sshbuf_put_string(ssh->state->outgoing_packet, v, len); 2484} 2485 2486int 2487sshpkt_put_cstring(struct ssh *ssh, const void *v) 2488{ 2489 return sshbuf_put_cstring(ssh->state->outgoing_packet, v); 2490} 2491 2492int 2493sshpkt_put_stringb(struct ssh *ssh, const struct sshbuf *v) 2494{ 2495 return sshbuf_put_stringb(ssh->state->outgoing_packet, v); 2496} 2497 2498#ifdef WITH_OPENSSL 2499int 2500sshpkt_put_ec(struct ssh *ssh, const EC_POINT *v, const EC_GROUP *g) 2501{ 2502 return sshbuf_put_ec(ssh->state->outgoing_packet, v, g); 2503} 2504 2505 2506int 2507sshpkt_put_bignum2(struct ssh *ssh, const BIGNUM *v) 2508{ 2509 return sshbuf_put_bignum2(ssh->state->outgoing_packet, v); 2510} 2511#endif /* WITH_OPENSSL */ 2512 2513/* fetch data from the incoming packet */ 2514 2515int 2516sshpkt_get(struct ssh *ssh, void *valp, size_t len) 2517{ 2518 return sshbuf_get(ssh->state->incoming_packet, valp, len); 2519} 2520 2521int 2522sshpkt_get_u8(struct ssh *ssh, u_char *valp) 2523{ 2524 return sshbuf_get_u8(ssh->state->incoming_packet, valp); 2525} 2526 2527int 2528sshpkt_get_u32(struct ssh *ssh, u_int32_t *valp) 2529{ 2530 return sshbuf_get_u32(ssh->state->incoming_packet, valp); 2531} 2532 2533int 2534sshpkt_get_u64(struct ssh *ssh, u_int64_t *valp) 2535{ 2536 return sshbuf_get_u64(ssh->state->incoming_packet, valp); 2537} 2538 2539int 2540sshpkt_get_string(struct ssh *ssh, u_char **valp, size_t *lenp) 2541{ 2542 return sshbuf_get_string(ssh->state->incoming_packet, valp, lenp); 2543} 2544 2545int 2546sshpkt_get_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp) 2547{ 2548 return sshbuf_get_string_direct(ssh->state->incoming_packet, valp, lenp); 2549} 2550 2551int 2552sshpkt_peek_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp) 2553{ 2554 return sshbuf_peek_string_direct(ssh->state->incoming_packet, valp, lenp); 2555} 2556 2557int 2558sshpkt_get_cstring(struct ssh *ssh, char **valp, size_t *lenp) 2559{ 2560 return sshbuf_get_cstring(ssh->state->incoming_packet, valp, lenp); 2561} 2562 2563int 2564sshpkt_getb_froms(struct ssh *ssh, struct sshbuf **valp) 2565{ 2566 return sshbuf_froms(ssh->state->incoming_packet, valp); 2567} 2568 2569#ifdef WITH_OPENSSL 2570int 2571sshpkt_get_ec(struct ssh *ssh, EC_POINT *v, const EC_GROUP *g) 2572{ 2573 return sshbuf_get_ec(ssh->state->incoming_packet, v, g); 2574} 2575 2576int 2577sshpkt_get_bignum2(struct ssh *ssh, BIGNUM **valp) 2578{ 2579 return sshbuf_get_bignum2(ssh->state->incoming_packet, valp); 2580} 2581#endif /* WITH_OPENSSL */ 2582 2583int 2584sshpkt_get_end(struct ssh *ssh) 2585{ 2586 if (sshbuf_len(ssh->state->incoming_packet) > 0) 2587 return SSH_ERR_UNEXPECTED_TRAILING_DATA; 2588 return 0; 2589} 2590 2591const u_char * 2592sshpkt_ptr(struct ssh *ssh, size_t *lenp) 2593{ 2594 if (lenp != NULL) 2595 *lenp = sshbuf_len(ssh->state->incoming_packet); 2596 return sshbuf_ptr(ssh->state->incoming_packet); 2597} 2598 2599/* start a new packet */ 2600 2601int 2602sshpkt_start(struct ssh *ssh, u_char type) 2603{ 2604 u_char buf[6]; /* u32 packet length, u8 pad len, u8 type */ 2605 2606 DBG(debug("packet_start[%d]", type)); 2607 memset(buf, 0, sizeof(buf)); 2608 buf[sizeof(buf) - 1] = type; 2609 sshbuf_reset(ssh->state->outgoing_packet); 2610 return sshbuf_put(ssh->state->outgoing_packet, buf, sizeof(buf)); 2611} 2612 2613static int 2614ssh_packet_send_mux(struct ssh *ssh) 2615{ 2616 struct session_state *state = ssh->state; 2617 u_char type, *cp; 2618 size_t len; 2619 int r; 2620 2621 if (ssh->kex) 2622 return SSH_ERR_INTERNAL_ERROR; 2623 len = sshbuf_len(state->outgoing_packet); 2624 if (len < 6) 2625 return SSH_ERR_INTERNAL_ERROR; 2626 cp = sshbuf_mutable_ptr(state->outgoing_packet); 2627 type = cp[5]; 2628 if (ssh_packet_log_type(type)) 2629 debug3_f("type %u", type); 2630 /* drop everything, but the connection protocol */ 2631 if (type >= SSH2_MSG_CONNECTION_MIN && 2632 type <= SSH2_MSG_CONNECTION_MAX) { 2633 POKE_U32(cp, len - 4); 2634 if ((r = sshbuf_putb(state->output, 2635 state->outgoing_packet)) != 0) 2636 return r; 2637 /* sshbuf_dump(state->output, stderr); */ 2638 } 2639 sshbuf_reset(state->outgoing_packet); 2640 return 0; 2641} 2642 2643/* 2644 * 9.2. Ignored Data Message 2645 * 2646 * byte SSH_MSG_IGNORE 2647 * string data 2648 * 2649 * All implementations MUST understand (and ignore) this message at any 2650 * time (after receiving the protocol version). No implementation is 2651 * required to send them. This message can be used as an additional 2652 * protection measure against advanced traffic analysis techniques. 2653 */ 2654int 2655sshpkt_msg_ignore(struct ssh *ssh, u_int nbytes) 2656{ 2657 u_int32_t rnd = 0; 2658 int r; 2659 u_int i; 2660 2661 if ((r = sshpkt_start(ssh, SSH2_MSG_IGNORE)) != 0 || 2662 (r = sshpkt_put_u32(ssh, nbytes)) != 0) 2663 return r; 2664 for (i = 0; i < nbytes; i++) { 2665 if (i % 4 == 0) 2666 rnd = arc4random(); 2667 if ((r = sshpkt_put_u8(ssh, (u_char)rnd & 0xff)) != 0) 2668 return r; 2669 rnd >>= 8; 2670 } 2671 return 0; 2672} 2673 2674/* send it */ 2675 2676int 2677sshpkt_sendx(struct ssh *ssh) 2678{ 2679 if (ssh->state && ssh->state->mux) 2680 return ssh_packet_send_mux(ssh); 2681 return ssh_packet_send2(ssh); 2682} 2683 2684int 2685sshpkt_send(struct ssh *ssh) 2686{ 2687 int r = sshpkt_sendx(ssh); 2688 return r < 0 ? r : 0; 2689} 2690 2691int 2692sshpkt_disconnect(struct ssh *ssh, const char *fmt,...) 2693{ 2694 char buf[1024]; 2695 va_list args; 2696 int r; 2697 2698 va_start(args, fmt); 2699 vsnprintf(buf, sizeof(buf), fmt, args); 2700 va_end(args); 2701 2702 if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 || 2703 (r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_PROTOCOL_ERROR)) != 0 || 2704 (r = sshpkt_put_cstring(ssh, buf)) != 0 || 2705 (r = sshpkt_put_cstring(ssh, "")) != 0 || 2706 (r = sshpkt_send(ssh)) != 0) 2707 return r; 2708 return 0; 2709} 2710 2711/* roundup current message to pad bytes */ 2712int 2713sshpkt_add_padding(struct ssh *ssh, u_char pad) 2714{ 2715 ssh->state->extra_pad = pad; 2716 return 0; 2717} 2718 2719int 2720ssh_packet_authentication_state(struct ssh *ssh) 2721{ 2722 return ssh->state->after_authentication; 2723} 2724