crypto/openssh/packet.c

   1 /* $OpenBSD: packet.c,v 1.192 2014/02/02 03:44:31 djm Exp $ */
   2 /* $FreeBSD$ */
   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("$FreeBSD$");
  43
  44 #include <sys/types.h>
  45 #include "openbsd-compat/sys-queue.h"
  46 #include <sys/param.h>
  47 #include <sys/socket.h>
  48 #ifdef HAVE_SYS_TIME_H
  49 # include <sys/time.h>
  50 #endif
  51
  52 #include <netinet/in.h>
  53 #include <netinet/ip.h>
  54 #include <arpa/inet.h>
  55
  56 #include <errno.h>
  57 #include <stdarg.h>
  58 #include <stdio.h>
  59 #include <stdlib.h>
  60 #include <string.h>
  61 #include <unistd.h>
  62 #include <signal.h>
  63 #include <time.h>
  64
  65 #include "xmalloc.h"
  66 #include "buffer.h"
  67 #include "packet.h"
  68 #include "crc32.h"
  69 #include "compress.h"
  70 #include "deattack.h"
  71 #include "channels.h"
  72 #include "compat.h"
  73 #include "ssh1.h"
  74 #include "ssh2.h"
  75 #include "cipher.h"
  76 #include "key.h"
  77 #include "kex.h"
  78 #include "mac.h"
  79 #include "log.h"
  80 #include "canohost.h"
  81 #include "misc.h"
  82 #include "ssh.h"
  83 #include "roaming.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
  93 struct packet_state {
  94         u_int32_t seqnr;
  95         u_int32_t packets;
  96         u_int64_t blocks;
  97         u_int64_t bytes;
  98 };
  99
 100 struct packet {
 101         TAILQ_ENTRY(packet) next;
 102         u_char type;
 103         Buffer payload;
 104 };
 105
 106 struct 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         CipherContext receive_context;
 121
 122         /* Encryption context for sending data.  Only used for encryption. */
 123         CipherContext send_context;
 124
 125         /* Buffer for raw input data from the socket. */
 126         Buffer input;
 127
 128         /* Buffer for raw output data going to the socket. */
 129         Buffer output;
 130
 131         /* Buffer for the partial outgoing packet being constructed. */
 132         Buffer outgoing_packet;
 133
 134         /* Buffer for the incoming packet currently being processed. */
 135         Buffer incoming_packet;
 136
 137         /* Scratch buffer for packet compression/decompression. */
 138         Buffer compression_buffer;
 139         int compression_buffer_ready;
 140
 141         /*
 142          * Flag indicating whether packet compression/decompression is
 143          * enabled.
 144          */
 145         int packet_compression;
 146
 147         /* default maximum packet size */
 148         u_int max_packet_size;
 149
 150         /* Flag indicating whether this module has been initialized. */
 151         int initialized;
 152
 153         /* Set to true if the connection is interactive. */
 154         int interactive_mode;
 155
 156         /* Set to true if we are the server side. */
 157         int server_side;
 158
 159         /* Set to true if we are authenticated. */
 160         int after_authentication;
 161
 162         int keep_alive_timeouts;
 163
 164         /* The maximum time that we will wait to send or receive a packet */
 165         int packet_timeout_ms;
 166
 167         /* Session key information for Encryption and MAC */
 168         Newkeys *newkeys[MODE_MAX];
 169         struct packet_state p_read, p_send;
 170
 171         /* Volume-based rekeying */
 172         u_int64_t max_blocks_in, max_blocks_out;
 173         u_int32_t rekey_limit;
 174
 175         /* Time-based rekeying */
 176         time_t rekey_interval;  /* how often in seconds */
 177         time_t rekey_time;      /* time of last rekeying */
 178
 179         /* Session key for protocol v1 */
 180         u_char ssh1_key[SSH_SESSION_KEY_LENGTH];
 181         u_int ssh1_keylen;
 182
 183         /* roundup current message to extra_pad bytes */
 184         u_char extra_pad;
 185
 186         /* XXX discard incoming data after MAC error */
 187         u_int packet_discard;
 188         Mac *packet_discard_mac;
 189
 190         /* Used in packet_read_poll2() */
 191         u_int packlen;
 192
 193         /* Used in packet_send2 */
 194         int rekeying;
 195
 196         /* Used in packet_set_interactive */
 197         int set_interactive_called;
 198
 199         /* Used in packet_set_maxsize */
 200         int set_maxsize_called;
 201
 202         TAILQ_HEAD(, packet) outgoing;
 203 };
 204
 205 static struct session_state *active_state, *backup_state;
 206 #ifdef  NONE_CIPHER_ENABLED
 207 static int rekey_requested = 0;
 208 #endif
 209
 210 static struct session_state *
 211 alloc_session_state(void)
 212 {
 213         struct session_state *s = xcalloc(1, sizeof(*s));
 214
 215         s->connection_in = -1;
 216         s->connection_out = -1;
 217         s->max_packet_size = 32768;
 218         s->packet_timeout_ms = -1;
 219         return s;
 220 }
 221
 222 /*
 223  * Sets the descriptors used for communication.  Disables encryption until
 224  * packet_set_encryption_key is called.
 225  */
 226 void
 227 packet_set_connection(int fd_in, int fd_out)
 228 {
 229         const Cipher *none = cipher_by_name("none");
 230
 231         if (none == NULL)
 232                 fatal("packet_set_connection: cannot load cipher 'none'");
 233         if (active_state == NULL)
 234                 active_state = alloc_session_state();
 235         active_state->connection_in = fd_in;
 236         active_state->connection_out = fd_out;
 237         cipher_init(&active_state->send_context, none, (const u_char *)"",
 238             0, NULL, 0, CIPHER_ENCRYPT);
 239         cipher_init(&active_state->receive_context, none, (const u_char *)"",
 240             0, NULL, 0, CIPHER_DECRYPT);
 241         active_state->newkeys[MODE_IN] = active_state->newkeys[MODE_OUT] = NULL;
 242         if (!active_state->initialized) {
 243                 active_state->initialized = 1;
 244                 buffer_init(&active_state->input);
 245                 buffer_init(&active_state->output);
 246                 buffer_init(&active_state->outgoing_packet);
 247                 buffer_init(&active_state->incoming_packet);
 248                 TAILQ_INIT(&active_state->outgoing);
 249                 active_state->p_send.packets = active_state->p_read.packets = 0;
 250         }
 251 }
 252
 253 void
 254 packet_set_timeout(int timeout, int count)
 255 {
 256         if (timeout <= 0 || count <= 0) {
 257                 active_state->packet_timeout_ms = -1;
 258                 return;
 259         }
 260         if ((INT_MAX / 1000) / count < timeout)
 261                 active_state->packet_timeout_ms = INT_MAX;
 262         else
 263                 active_state->packet_timeout_ms = timeout * count * 1000;
 264 }
 265
 266 static void
 267 packet_stop_discard(void)
 268 {
 269         if (active_state->packet_discard_mac) {
 270                 char buf[1024];
 271
 272                 memset(buf, 'a', sizeof(buf));
 273                 while (buffer_len(&active_state->incoming_packet) <
 274                     PACKET_MAX_SIZE)
 275                         buffer_append(&active_state->incoming_packet, buf,
 276                             sizeof(buf));
 277                 (void) mac_compute(active_state->packet_discard_mac,
 278                     active_state->p_read.seqnr,
 279                     buffer_ptr(&active_state->incoming_packet),
 280                     PACKET_MAX_SIZE);
 281         }
 282         logit("Finished discarding for %.200s", get_remote_ipaddr());
 283         cleanup_exit(255);
 284 }
 285
 286 static void
 287 packet_start_discard(Enc *enc, Mac *mac, u_int packet_length, u_int discard)
 288 {
 289         if (enc == NULL || !cipher_is_cbc(enc->cipher) || (mac && mac->etm))
 290                 packet_disconnect("Packet corrupt");
 291         if (packet_length != PACKET_MAX_SIZE && mac && mac->enabled)
 292                 active_state->packet_discard_mac = mac;
 293         if (buffer_len(&active_state->input) >= discard)
 294                 packet_stop_discard();
 295         active_state->packet_discard = discard -
 296             buffer_len(&active_state->input);
 297 }
 298
 299 /* Returns 1 if remote host is connected via socket, 0 if not. */
 300
 301 int
 302 packet_connection_is_on_socket(void)
 303 {
 304         struct sockaddr_storage from, to;
 305         socklen_t fromlen, tolen;
 306
 307         /* filedescriptors in and out are the same, so it's a socket */
 308         if (active_state->connection_in == active_state->connection_out)
 309                 return 1;
 310         fromlen = sizeof(from);
 311         memset(&from, 0, sizeof(from));
 312         if (getpeername(active_state->connection_in, (struct sockaddr *)&from,
 313             &fromlen) < 0)
 314                 return 0;
 315         tolen = sizeof(to);
 316         memset(&to, 0, sizeof(to));
 317         if (getpeername(active_state->connection_out, (struct sockaddr *)&to,
 318             &tolen) < 0)
 319                 return 0;
 320         if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0)
 321                 return 0;
 322         if (from.ss_family != AF_INET && from.ss_family != AF_INET6)
 323                 return 0;
 324         return 1;
 325 }
 326
 327 /*
 328  * Exports an IV from the CipherContext required to export the key
 329  * state back from the unprivileged child to the privileged parent
 330  * process.
 331  */
 332
 333 void
 334 packet_get_keyiv(int mode, u_char *iv, u_int len)
 335 {
 336         CipherContext *cc;
 337
 338         if (mode == MODE_OUT)
 339                 cc = &active_state->send_context;
 340         else
 341                 cc = &active_state->receive_context;
 342
 343         cipher_get_keyiv(cc, iv, len);
 344 }
 345
 346 int
 347 packet_get_keycontext(int mode, u_char *dat)
 348 {
 349         CipherContext *cc;
 350
 351         if (mode == MODE_OUT)
 352                 cc = &active_state->send_context;
 353         else
 354                 cc = &active_state->receive_context;
 355
 356         return (cipher_get_keycontext(cc, dat));
 357 }
 358
 359 void
 360 packet_set_keycontext(int mode, u_char *dat)
 361 {
 362         CipherContext *cc;
 363
 364         if (mode == MODE_OUT)
 365                 cc = &active_state->send_context;
 366         else
 367                 cc = &active_state->receive_context;
 368
 369         cipher_set_keycontext(cc, dat);
 370 }
 371
 372 int
 373 packet_get_keyiv_len(int mode)
 374 {
 375         CipherContext *cc;
 376
 377         if (mode == MODE_OUT)
 378                 cc = &active_state->send_context;
 379         else
 380                 cc = &active_state->receive_context;
 381
 382         return (cipher_get_keyiv_len(cc));
 383 }
 384
 385 void
 386 packet_set_iv(int mode, u_char *dat)
 387 {
 388         CipherContext *cc;
 389
 390         if (mode == MODE_OUT)
 391                 cc = &active_state->send_context;
 392         else
 393                 cc = &active_state->receive_context;
 394
 395         cipher_set_keyiv(cc, dat);
 396 }
 397
 398 int
 399 packet_get_ssh1_cipher(void)
 400 {
 401         return (cipher_get_number(active_state->receive_context.cipher));
 402 }
 403
 404 void
 405 packet_get_state(int mode, u_int32_t *seqnr, u_int64_t *blocks,
 406     u_int32_t *packets, u_int64_t *bytes)
 407 {
 408         struct packet_state *state;
 409
 410         state = (mode == MODE_IN) ?
 411             &active_state->p_read : &active_state->p_send;
 412         if (seqnr)
 413                 *seqnr = state->seqnr;
 414         if (blocks)
 415                 *blocks = state->blocks;
 416         if (packets)
 417                 *packets = state->packets;
 418         if (bytes)
 419                 *bytes = state->bytes;
 420 }
 421
 422 void
 423 packet_set_state(int mode, u_int32_t seqnr, u_int64_t blocks, u_int32_t packets,
 424     u_int64_t bytes)
 425 {
 426         struct packet_state *state;
 427
 428         state = (mode == MODE_IN) ?
 429             &active_state->p_read : &active_state->p_send;
 430         state->seqnr = seqnr;
 431         state->blocks = blocks;
 432         state->packets = packets;
 433         state->bytes = bytes;
 434 }
 435
 436 static int
 437 packet_connection_af(void)
 438 {
 439         struct sockaddr_storage to;
 440         socklen_t tolen = sizeof(to);
 441
 442         memset(&to, 0, sizeof(to));
 443         if (getsockname(active_state->connection_out, (struct sockaddr *)&to,
 444             &tolen) < 0)
 445                 return 0;
 446 #ifdef IPV4_IN_IPV6
 447         if (to.ss_family == AF_INET6 &&
 448             IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&to)->sin6_addr))
 449                 return AF_INET;
 450 #endif
 451         return to.ss_family;
 452 }
 453
 454 /* Sets the connection into non-blocking mode. */
 455
 456 void
 457 packet_set_nonblocking(void)
 458 {
 459         /* Set the socket into non-blocking mode. */
 460         set_nonblock(active_state->connection_in);
 461
 462         if (active_state->connection_out != active_state->connection_in)
 463                 set_nonblock(active_state->connection_out);
 464 }
 465
 466 /* Returns the socket used for reading. */
 467
 468 int
 469 packet_get_connection_in(void)
 470 {
 471         return active_state->connection_in;
 472 }
 473
 474 /* Returns the descriptor used for writing. */
 475
 476 int
 477 packet_get_connection_out(void)
 478 {
 479         return active_state->connection_out;
 480 }
 481
 482 /* Closes the connection and clears and frees internal data structures. */
 483
 484 void
 485 packet_close(void)
 486 {
 487         if (!active_state->initialized)
 488                 return;
 489         active_state->initialized = 0;
 490         if (active_state->connection_in == active_state->connection_out) {
 491                 shutdown(active_state->connection_out, SHUT_RDWR);
 492                 close(active_state->connection_out);
 493         } else {
 494                 close(active_state->connection_in);
 495                 close(active_state->connection_out);
 496         }
 497         buffer_free(&active_state->input);
 498         buffer_free(&active_state->output);
 499         buffer_free(&active_state->outgoing_packet);
 500         buffer_free(&active_state->incoming_packet);
 501         if (active_state->compression_buffer_ready) {
 502                 buffer_free(&active_state->compression_buffer);
 503                 buffer_compress_uninit();
 504         }
 505         cipher_cleanup(&active_state->send_context);
 506         cipher_cleanup(&active_state->receive_context);
 507 }
 508
 509 /* Sets remote side protocol flags. */
 510
 511 void
 512 packet_set_protocol_flags(u_int protocol_flags)
 513 {
 514         active_state->remote_protocol_flags = protocol_flags;
 515 }
 516
 517 /* Returns the remote protocol flags set earlier by the above function. */
 518
 519 u_int
 520 packet_get_protocol_flags(void)
 521 {
 522         return active_state->remote_protocol_flags;
 523 }
 524
 525 /*
 526  * Starts packet compression from the next packet on in both directions.
 527  * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip.
 528  */
 529
 530 static void
 531 packet_init_compression(void)
 532 {
 533         if (active_state->compression_buffer_ready == 1)
 534                 return;
 535         active_state->compression_buffer_ready = 1;
 536         buffer_init(&active_state->compression_buffer);
 537 }
 538
 539 void
 540 packet_start_compression(int level)
 541 {
 542         if (active_state->packet_compression && !compat20)
 543                 fatal("Compression already enabled.");
 544         active_state->packet_compression = 1;
 545         packet_init_compression();
 546         buffer_compress_init_send(level);
 547         buffer_compress_init_recv();
 548 }
 549
 550 /*
 551  * Causes any further packets to be encrypted using the given key.  The same
 552  * key is used for both sending and reception.  However, both directions are
 553  * encrypted independently of each other.
 554  */
 555
 556 void
 557 packet_set_encryption_key(const u_char *key, u_int keylen, int number)
 558 {
 559         const Cipher *cipher = cipher_by_number(number);
 560
 561         if (cipher == NULL)
 562                 fatal("packet_set_encryption_key: unknown cipher number %d", number);
 563         if (keylen < 20)
 564                 fatal("packet_set_encryption_key: keylen too small: %d", keylen);
 565         if (keylen > SSH_SESSION_KEY_LENGTH)
 566                 fatal("packet_set_encryption_key: keylen too big: %d", keylen);
 567         memcpy(active_state->ssh1_key, key, keylen);
 568         active_state->ssh1_keylen = keylen;
 569         cipher_init(&active_state->send_context, cipher, key, keylen, NULL,
 570             0, CIPHER_ENCRYPT);
 571         cipher_init(&active_state->receive_context, cipher, key, keylen, NULL,
 572             0, CIPHER_DECRYPT);
 573 }
 574
 575 u_int
 576 packet_get_encryption_key(u_char *key)
 577 {
 578         if (key == NULL)
 579                 return (active_state->ssh1_keylen);
 580         memcpy(key, active_state->ssh1_key, active_state->ssh1_keylen);
 581         return (active_state->ssh1_keylen);
 582 }
 583
 584 /* Start constructing a packet to send. */
 585 void
 586 packet_start(u_char type)
 587 {
 588         u_char buf[9];
 589         int len;
 590
 591         DBG(debug("packet_start[%d]", type));
 592         len = compat20 ? 6 : 9;
 593         memset(buf, 0, len - 1);
 594         buf[len - 1] = type;
 595         buffer_clear(&active_state->outgoing_packet);
 596         buffer_append(&active_state->outgoing_packet, buf, len);
 597 }
 598
 599 /* Append payload. */
 600 void
 601 packet_put_char(int value)
 602 {
 603         char ch = value;
 604
 605         buffer_append(&active_state->outgoing_packet, &ch, 1);
 606 }
 607
 608 void
 609 packet_put_int(u_int value)
 610 {
 611         buffer_put_int(&active_state->outgoing_packet, value);
 612 }
 613
 614 void
 615 packet_put_int64(u_int64_t value)
 616 {
 617         buffer_put_int64(&active_state->outgoing_packet, value);
 618 }
 619
 620 void
 621 packet_put_string(const void *buf, u_int len)
 622 {
 623         buffer_put_string(&active_state->outgoing_packet, buf, len);
 624 }
 625
 626 void
 627 packet_put_cstring(const char *str)
 628 {
 629         buffer_put_cstring(&active_state->outgoing_packet, str);
 630 }
 631
 632 void
 633 packet_put_raw(const void *buf, u_int len)
 634 {
 635         buffer_append(&active_state->outgoing_packet, buf, len);
 636 }
 637
 638 void
 639 packet_put_bignum(BIGNUM * value)
 640 {
 641         buffer_put_bignum(&active_state->outgoing_packet, value);
 642 }
 643
 644 void
 645 packet_put_bignum2(BIGNUM * value)
 646 {
 647         buffer_put_bignum2(&active_state->outgoing_packet, value);
 648 }
 649
 650 #ifdef OPENSSL_HAS_ECC
 651 void
 652 packet_put_ecpoint(const EC_GROUP *curve, const EC_POINT *point)
 653 {
 654         buffer_put_ecpoint(&active_state->outgoing_packet, curve, point);
 655 }
 656 #endif
 657
 658 /*
 659  * Finalizes and sends the packet.  If the encryption key has been set,
 660  * encrypts the packet before sending.
 661  */
 662
 663 static void
 664 packet_send1(void)
 665 {
 666         u_char buf[8], *cp;
 667         int i, padding, len;
 668         u_int checksum;
 669         u_int32_t rnd = 0;
 670
 671         /*
 672          * If using packet compression, compress the payload of the outgoing
 673          * packet.
 674          */
 675         if (active_state->packet_compression) {
 676                 buffer_clear(&active_state->compression_buffer);
 677                 /* Skip padding. */
 678                 buffer_consume(&active_state->outgoing_packet, 8);
 679                 /* padding */
 680                 buffer_append(&active_state->compression_buffer,
 681                     "\0\0\0\0\0\0\0\0", 8);
 682                 buffer_compress(&active_state->outgoing_packet,
 683                     &active_state->compression_buffer);
 684                 buffer_clear(&active_state->outgoing_packet);
 685                 buffer_append(&active_state->outgoing_packet,
 686                     buffer_ptr(&active_state->compression_buffer),
 687                     buffer_len(&active_state->compression_buffer));
 688         }
 689         /* Compute packet length without padding (add checksum, remove padding). */
 690         len = buffer_len(&active_state->outgoing_packet) + 4 - 8;
 691
 692         /* Insert padding. Initialized to zero in packet_start1() */
 693         padding = 8 - len % 8;
 694         if (!active_state->send_context.plaintext) {
 695                 cp = buffer_ptr(&active_state->outgoing_packet);
 696                 for (i = 0; i < padding; i++) {
 697                         if (i % 4 == 0)
 698                                 rnd = arc4random();
 699                         cp[7 - i] = rnd & 0xff;
 700                         rnd >>= 8;
 701                 }
 702         }
 703         buffer_consume(&active_state->outgoing_packet, 8 - padding);
 704
 705         /* Add check bytes. */
 706         checksum = ssh_crc32(buffer_ptr(&active_state->outgoing_packet),
 707             buffer_len(&active_state->outgoing_packet));
 708         put_u32(buf, checksum);
 709         buffer_append(&active_state->outgoing_packet, buf, 4);
 710
 711 #ifdef PACKET_DEBUG
 712         fprintf(stderr, "packet_send plain: ");
 713         buffer_dump(&active_state->outgoing_packet);
 714 #endif
 715
 716         /* Append to output. */
 717         put_u32(buf, len);
 718         buffer_append(&active_state->output, buf, 4);
 719         cp = buffer_append_space(&active_state->output,
 720             buffer_len(&active_state->outgoing_packet));
 721         if (cipher_crypt(&active_state->send_context, 0, cp,
 722             buffer_ptr(&active_state->outgoing_packet),
 723             buffer_len(&active_state->outgoing_packet), 0, 0) != 0)
 724                 fatal("%s: cipher_crypt failed", __func__);
 725
 726 #ifdef PACKET_DEBUG
 727         fprintf(stderr, "encrypted: ");
 728         buffer_dump(&active_state->output);
 729 #endif
 730         active_state->p_send.packets++;
 731         active_state->p_send.bytes += len +
 732             buffer_len(&active_state->outgoing_packet);
 733         buffer_clear(&active_state->outgoing_packet);
 734
 735         /*
 736          * Note that the packet is now only buffered in output.  It won't be
 737          * actually sent until packet_write_wait or packet_write_poll is
 738          * called.
 739          */
 740 }
 741
 742 void
 743 set_newkeys(int mode)
 744 {
 745         Enc *enc;
 746         Mac *mac;
 747         Comp *comp;
 748         CipherContext *cc;
 749         u_int64_t *max_blocks;
 750         int crypt_type;
 751
 752         debug2("set_newkeys: mode %d", mode);
 753
 754         if (mode == MODE_OUT) {
 755                 cc = &active_state->send_context;
 756                 crypt_type = CIPHER_ENCRYPT;
 757                 active_state->p_send.packets = active_state->p_send.blocks = 0;
 758                 max_blocks = &active_state->max_blocks_out;
 759         } else {
 760                 cc = &active_state->receive_context;
 761                 crypt_type = CIPHER_DECRYPT;
 762                 active_state->p_read.packets = active_state->p_read.blocks = 0;
 763                 max_blocks = &active_state->max_blocks_in;
 764         }
 765         if (active_state->newkeys[mode] != NULL) {
 766                 debug("set_newkeys: rekeying");
 767                 cipher_cleanup(cc);
 768                 enc  = &active_state->newkeys[mode]->enc;
 769                 mac  = &active_state->newkeys[mode]->mac;
 770                 comp = &active_state->newkeys[mode]->comp;
 771                 mac_clear(mac);
 772                 explicit_bzero(enc->iv,  enc->iv_len);
 773                 explicit_bzero(enc->key, enc->key_len);
 774                 explicit_bzero(mac->key, mac->key_len);
 775                 free(enc->name);
 776                 free(enc->iv);
 777                 free(enc->key);
 778                 free(mac->name);
 779                 free(mac->key);
 780                 free(comp->name);
 781                 free(active_state->newkeys[mode]);
 782         }
 783         active_state->newkeys[mode] = kex_get_newkeys(mode);
 784         if (active_state->newkeys[mode] == NULL)
 785                 fatal("newkeys: no keys for mode %d", mode);
 786         enc  = &active_state->newkeys[mode]->enc;
 787         mac  = &active_state->newkeys[mode]->mac;
 788         comp = &active_state->newkeys[mode]->comp;
 789         if (cipher_authlen(enc->cipher) == 0 && mac_init(mac) == 0)
 790                 mac->enabled = 1;
 791         DBG(debug("cipher_init_context: %d", mode));
 792         cipher_init(cc, enc->cipher, enc->key, enc->key_len,
 793             enc->iv, enc->iv_len, crypt_type);
 794         /* Deleting the keys does not gain extra security */
 795         /* explicit_bzero(enc->iv,  enc->block_size);
 796            explicit_bzero(enc->key, enc->key_len);
 797            explicit_bzero(mac->key, mac->key_len); */
 798         if ((comp->type == COMP_ZLIB ||
 799             (comp->type == COMP_DELAYED &&
 800              active_state->after_authentication)) && comp->enabled == 0) {
 801                 packet_init_compression();
 802                 if (mode == MODE_OUT)
 803                         buffer_compress_init_send(6);
 804                 else
 805                         buffer_compress_init_recv();
 806                 comp->enabled = 1;
 807         }
 808         /*
 809          * The 2^(blocksize*2) limit is too expensive for 3DES,
 810          * blowfish, etc, so enforce a 1GB limit for small blocksizes.
 811          */
 812         if (enc->block_size >= 16)
 813                 *max_blocks = (u_int64_t)1 << (enc->block_size*2);
 814         else
 815                 *max_blocks = ((u_int64_t)1 << 30) / enc->block_size;
 816         if (active_state->rekey_limit)
 817                 *max_blocks = MIN(*max_blocks,
 818                     active_state->rekey_limit / enc->block_size);
 819 }
 820
 821 /*
 822  * Delayed compression for SSH2 is enabled after authentication:
 823  * This happens on the server side after a SSH2_MSG_USERAUTH_SUCCESS is sent,
 824  * and on the client side after a SSH2_MSG_USERAUTH_SUCCESS is received.
 825  */
 826 static void
 827 packet_enable_delayed_compress(void)
 828 {
 829         Comp *comp = NULL;
 830         int mode;
 831
 832         /*
 833          * Remember that we are past the authentication step, so rekeying
 834          * with COMP_DELAYED will turn on compression immediately.
 835          */
 836         active_state->after_authentication = 1;
 837         for (mode = 0; mode < MODE_MAX; mode++) {
 838                 /* protocol error: USERAUTH_SUCCESS received before NEWKEYS */
 839                 if (active_state->newkeys[mode] == NULL)
 840                         continue;
 841                 comp = &active_state->newkeys[mode]->comp;
 842                 if (comp && !comp->enabled && comp->type == COMP_DELAYED) {
 843                         packet_init_compression();
 844                         if (mode == MODE_OUT)
 845                                 buffer_compress_init_send(6);
 846                         else
 847                                 buffer_compress_init_recv();
 848                         comp->enabled = 1;
 849                 }
 850         }
 851 }
 852
 853 /*
 854  * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue)
 855  */
 856 static void
 857 packet_send2_wrapped(void)
 858 {
 859         u_char type, *cp, *macbuf = NULL;
 860         u_char padlen, pad = 0;
 861         u_int i, len, authlen = 0, aadlen = 0;
 862         u_int32_t rnd = 0;
 863         Enc *enc   = NULL;
 864         Mac *mac   = NULL;
 865         Comp *comp = NULL;
 866         int block_size;
 867
 868         if (active_state->newkeys[MODE_OUT] != NULL) {
 869                 enc  = &active_state->newkeys[MODE_OUT]->enc;
 870                 mac  = &active_state->newkeys[MODE_OUT]->mac;
 871                 comp = &active_state->newkeys[MODE_OUT]->comp;
 872                 /* disable mac for authenticated encryption */
 873                 if ((authlen = cipher_authlen(enc->cipher)) != 0)
 874                         mac = NULL;
 875         }
 876         block_size = enc ? enc->block_size : 8;
 877         aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0;
 878
 879         cp = buffer_ptr(&active_state->outgoing_packet);
 880         type = cp[5];
 881
 882 #ifdef PACKET_DEBUG
 883         fprintf(stderr, "plain:     ");
 884         buffer_dump(&active_state->outgoing_packet);
 885 #endif
 886
 887         if (comp && comp->enabled) {
 888                 len = buffer_len(&active_state->outgoing_packet);
 889                 /* skip header, compress only payload */
 890                 buffer_consume(&active_state->outgoing_packet, 5);
 891                 buffer_clear(&active_state->compression_buffer);
 892                 buffer_compress(&active_state->outgoing_packet,
 893                     &active_state->compression_buffer);
 894                 buffer_clear(&active_state->outgoing_packet);
 895                 buffer_append(&active_state->outgoing_packet, "\0\0\0\0\0", 5);
 896                 buffer_append(&active_state->outgoing_packet,
 897                     buffer_ptr(&active_state->compression_buffer),
 898                     buffer_len(&active_state->compression_buffer));
 899                 DBG(debug("compression: raw %d compressed %d", len,
 900                     buffer_len(&active_state->outgoing_packet)));
 901         }
 902
 903         /* sizeof (packet_len + pad_len + payload) */
 904         len = buffer_len(&active_state->outgoing_packet);
 905
 906         /*
 907          * calc size of padding, alloc space, get random data,
 908          * minimum padding is 4 bytes
 909          */
 910         len -= aadlen; /* packet length is not encrypted for EtM modes */
 911         padlen = block_size - (len % block_size);
 912         if (padlen < 4)
 913                 padlen += block_size;
 914         if (active_state->extra_pad) {
 915                 /* will wrap if extra_pad+padlen > 255 */
 916                 active_state->extra_pad =
 917                     roundup(active_state->extra_pad, block_size);
 918                 pad = active_state->extra_pad -
 919                     ((len + padlen) % active_state->extra_pad);
 920                 debug3("packet_send2: adding %d (len %d padlen %d extra_pad %d)",
 921                     pad, len, padlen, active_state->extra_pad);
 922                 padlen += pad;
 923                 active_state->extra_pad = 0;
 924         }
 925         cp = buffer_append_space(&active_state->outgoing_packet, padlen);
 926         if (enc && !active_state->send_context.plaintext) {
 927                 /* random padding */
 928                 for (i = 0; i < padlen; i++) {
 929                         if (i % 4 == 0)
 930                                 rnd = arc4random();
 931                         cp[i] = rnd & 0xff;
 932                         rnd >>= 8;
 933                 }
 934         } else {
 935                 /* clear padding */
 936                 explicit_bzero(cp, padlen);
 937         }
 938         /* sizeof (packet_len + pad_len + payload + padding) */
 939         len = buffer_len(&active_state->outgoing_packet);
 940         cp = buffer_ptr(&active_state->outgoing_packet);
 941         /* packet_length includes payload, padding and padding length field */
 942         put_u32(cp, len - 4);
 943         cp[4] = padlen;
 944         DBG(debug("send: len %d (includes padlen %d, aadlen %d)",
 945             len, padlen, aadlen));
 946
 947         /* compute MAC over seqnr and packet(length fields, payload, padding) */
 948         if (mac && mac->enabled && !mac->etm) {
 949                 macbuf = mac_compute(mac, active_state->p_send.seqnr,
 950                     buffer_ptr(&active_state->outgoing_packet), len);
 951                 DBG(debug("done calc MAC out #%d", active_state->p_send.seqnr));
 952         }
 953         /* encrypt packet and append to output buffer. */
 954         cp = buffer_append_space(&active_state->output, len + authlen);
 955         if (cipher_crypt(&active_state->send_context, active_state->p_send.seqnr,
 956             cp, buffer_ptr(&active_state->outgoing_packet),
 957             len - aadlen, aadlen, authlen) != 0)
 958                 fatal("%s: cipher_crypt failed", __func__);
 959         /* append unencrypted MAC */
 960         if (mac && mac->enabled) {
 961                 if (mac->etm) {
 962                         /* EtM: compute mac over aadlen + cipher text */
 963                         macbuf = mac_compute(mac,
 964                             active_state->p_send.seqnr, cp, len);
 965                         DBG(debug("done calc MAC(EtM) out #%d",
 966                             active_state->p_send.seqnr));
 967                 }
 968                 buffer_append(&active_state->output, macbuf, mac->mac_len);
 969         }
 970 #ifdef PACKET_DEBUG
 971         fprintf(stderr, "encrypted: ");
 972         buffer_dump(&active_state->output);
 973 #endif
 974         /* increment sequence number for outgoing packets */
 975         if (++active_state->p_send.seqnr == 0)
 976                 logit("outgoing seqnr wraps around");
 977         if (++active_state->p_send.packets == 0)
 978                 if (!(datafellows & SSH_BUG_NOREKEY))
 979                         fatal("XXX too many packets with same key");
 980         active_state->p_send.blocks += len / block_size;
 981         active_state->p_send.bytes += len;
 982         buffer_clear(&active_state->outgoing_packet);
 983
 984         if (type == SSH2_MSG_NEWKEYS)
 985                 set_newkeys(MODE_OUT);
 986         else if (type == SSH2_MSG_USERAUTH_SUCCESS && active_state->server_side)
 987                 packet_enable_delayed_compress();
 988 }
 989
 990 static void
 991 packet_send2(void)
 992 {
 993         struct packet *p;
 994         u_char type, *cp;
 995
 996         cp = buffer_ptr(&active_state->outgoing_packet);
 997         type = cp[5];
 998
 999         /* during rekeying we can only send key exchange messages */
1000         if (active_state->rekeying) {
1001                 if ((type < SSH2_MSG_TRANSPORT_MIN) ||
1002                     (type > SSH2_MSG_TRANSPORT_MAX) ||
1003                     (type == SSH2_MSG_SERVICE_REQUEST) ||
1004                     (type == SSH2_MSG_SERVICE_ACCEPT)) {
1005                         debug("enqueue packet: %u", type);
1006                         p = xcalloc(1, sizeof(*p));
1007                         p->type = type;
1008                         memcpy(&p->payload, &active_state->outgoing_packet,
1009                             sizeof(Buffer));
1010                         buffer_init(&active_state->outgoing_packet);
1011                         TAILQ_INSERT_TAIL(&active_state->outgoing, p, next);
1012                         return;
1013                 }
1014         }
1015
1016         /* rekeying starts with sending KEXINIT */
1017         if (type == SSH2_MSG_KEXINIT)
1018                 active_state->rekeying = 1;
1019
1020         packet_send2_wrapped();
1021
1022         /* after a NEWKEYS message we can send the complete queue */
1023         if (type == SSH2_MSG_NEWKEYS) {
1024                 active_state->rekeying = 0;
1025                 active_state->rekey_time = monotime();
1026                 while ((p = TAILQ_FIRST(&active_state->outgoing))) {
1027                         type = p->type;
1028                         debug("dequeue packet: %u", type);
1029                         buffer_free(&active_state->outgoing_packet);
1030                         memcpy(&active_state->outgoing_packet, &p->payload,
1031                             sizeof(Buffer));
1032                         TAILQ_REMOVE(&active_state->outgoing, p, next);
1033                         free(p);
1034                         packet_send2_wrapped();
1035                 }
1036         }
1037 }
1038
1039 void
1040 packet_send(void)
1041 {
1042         if (compat20)
1043                 packet_send2();
1044         else
1045                 packet_send1();
1046         DBG(debug("packet_send done"));
1047 }
1048
1049 /*
1050  * Waits until a packet has been received, and returns its type.  Note that
1051  * no other data is processed until this returns, so this function should not
1052  * be used during the interactive session.
1053  */
1054
1055 int
1056 packet_read_seqnr(u_int32_t *seqnr_p)
1057 {
1058         int type, len, ret, cont, ms_remain = 0;
1059         fd_set *setp;
1060         char buf[8192];
1061         struct timeval timeout, start, *timeoutp = NULL;
1062
1063         DBG(debug("packet_read()"));
1064
1065         setp = (fd_set *)xcalloc(howmany(active_state->connection_in + 1,
1066             NFDBITS), sizeof(fd_mask));
1067
1068         /* Since we are blocking, ensure that all written packets have been sent. */
1069         packet_write_wait();
1070
1071         /* Stay in the loop until we have received a complete packet. */
1072         for (;;) {
1073                 /* Try to read a packet from the buffer. */
1074                 type = packet_read_poll_seqnr(seqnr_p);
1075                 if (!compat20 && (
1076                     type == SSH_SMSG_SUCCESS
1077                     || type == SSH_SMSG_FAILURE
1078                     || type == SSH_CMSG_EOF
1079                     || type == SSH_CMSG_EXIT_CONFIRMATION))
1080                         packet_check_eom();
1081                 /* If we got a packet, return it. */
1082                 if (type != SSH_MSG_NONE) {
1083                         free(setp);
1084                         return type;
1085                 }
1086                 /*
1087                  * Otherwise, wait for some data to arrive, add it to the
1088                  * buffer, and try again.
1089                  */
1090                 memset(setp, 0, howmany(active_state->connection_in + 1,
1091                     NFDBITS) * sizeof(fd_mask));
1092                 FD_SET(active_state->connection_in, setp);
1093
1094                 if (active_state->packet_timeout_ms > 0) {
1095                         ms_remain = active_state->packet_timeout_ms;
1096                         timeoutp = &timeout;
1097                 }
1098                 /* Wait for some data to arrive. */
1099                 for (;;) {
1100                         if (active_state->packet_timeout_ms != -1) {
1101                                 ms_to_timeval(&timeout, ms_remain);
1102                                 gettimeofday(&start, NULL);
1103                         }
1104                         if ((ret = select(active_state->connection_in + 1, setp,
1105                             NULL, NULL, timeoutp)) >= 0)
1106                                 break;
1107                         if (errno != EAGAIN && errno != EINTR &&
1108                             errno != EWOULDBLOCK)
1109                                 break;
1110                         if (active_state->packet_timeout_ms == -1)
1111                                 continue;
1112                         ms_subtract_diff(&start, &ms_remain);
1113                         if (ms_remain <= 0) {
1114                                 ret = 0;
1115                                 break;
1116                         }
1117                 }
1118                 if (ret == 0) {
1119                         logit("Connection to %.200s timed out while "
1120                             "waiting to read", get_remote_ipaddr());
1121                         cleanup_exit(255);
1122                 }
1123                 /* Read data from the socket. */
1124                 do {
1125                         cont = 0;
1126                         len = roaming_read(active_state->connection_in, buf,
1127                             sizeof(buf), &cont);
1128                 } while (len == 0 && cont);
1129                 if (len == 0) {
1130                         logit("Connection closed by %.200s", get_remote_ipaddr());
1131                         cleanup_exit(255);
1132                 }
1133                 if (len < 0)
1134                         fatal("Read from socket failed: %.100s", strerror(errno));
1135                 /* Append it to the buffer. */
1136                 packet_process_incoming(buf, len);
1137         }
1138         /* NOTREACHED */
1139 }
1140
1141 int
1142 packet_read(void)
1143 {
1144         return packet_read_seqnr(NULL);
1145 }
1146
1147 /*
1148  * Waits until a packet has been received, verifies that its type matches
1149  * that given, and gives a fatal error and exits if there is a mismatch.
1150  */
1151
1152 void
1153 packet_read_expect(int expected_type)
1154 {
1155         int type;
1156
1157         type = packet_read();
1158         if (type != expected_type)
1159                 packet_disconnect("Protocol error: expected packet type %d, got %d",
1160                     expected_type, type);
1161 }
1162
1163 /* Checks if a full packet is available in the data received so far via
1164  * packet_process_incoming.  If so, reads the packet; otherwise returns
1165  * SSH_MSG_NONE.  This does not wait for data from the connection.
1166  *
1167  * SSH_MSG_DISCONNECT is handled specially here.  Also,
1168  * SSH_MSG_IGNORE messages are skipped by this function and are never returned
1169  * to higher levels.
1170  */
1171
1172 static int
1173 packet_read_poll1(void)
1174 {
1175         u_int len, padded_len;
1176         u_char *cp, type;
1177         u_int checksum, stored_checksum;
1178
1179         /* Check if input size is less than minimum packet size. */
1180         if (buffer_len(&active_state->input) < 4 + 8)
1181                 return SSH_MSG_NONE;
1182         /* Get length of incoming packet. */
1183         cp = buffer_ptr(&active_state->input);
1184         len = get_u32(cp);
1185         if (len < 1 + 2 + 2 || len > 256 * 1024)
1186                 packet_disconnect("Bad packet length %u.", len);
1187         padded_len = (len + 8) & ~7;
1188
1189         /* Check if the packet has been entirely received. */
1190         if (buffer_len(&active_state->input) < 4 + padded_len)
1191                 return SSH_MSG_NONE;
1192
1193         /* The entire packet is in buffer. */
1194
1195         /* Consume packet length. */
1196         buffer_consume(&active_state->input, 4);
1197
1198         /*
1199          * Cryptographic attack detector for ssh
1200          * (C)1998 CORE-SDI, Buenos Aires Argentina
1201          * Ariel Futoransky(futo@core-sdi.com)
1202          */
1203         if (!active_state->receive_context.plaintext) {
1204                 switch (detect_attack(buffer_ptr(&active_state->input),
1205                     padded_len)) {
1206                 case DEATTACK_DETECTED:
1207                         packet_disconnect("crc32 compensation attack: "
1208                             "network attack detected");
1209                 case DEATTACK_DOS_DETECTED:
1210                         packet_disconnect("deattack denial of "
1211                             "service detected");
1212                 }
1213         }
1214
1215         /* Decrypt data to incoming_packet. */
1216         buffer_clear(&active_state->incoming_packet);
1217         cp = buffer_append_space(&active_state->incoming_packet, padded_len);
1218         if (cipher_crypt(&active_state->receive_context, 0, cp,
1219             buffer_ptr(&active_state->input), padded_len, 0, 0) != 0)
1220                 fatal("%s: cipher_crypt failed", __func__);
1221
1222         buffer_consume(&active_state->input, padded_len);
1223
1224 #ifdef PACKET_DEBUG
1225         fprintf(stderr, "read_poll plain: ");
1226         buffer_dump(&active_state->incoming_packet);
1227 #endif
1228
1229         /* Compute packet checksum. */
1230         checksum = ssh_crc32(buffer_ptr(&active_state->incoming_packet),
1231             buffer_len(&active_state->incoming_packet) - 4);
1232
1233         /* Skip padding. */
1234         buffer_consume(&active_state->incoming_packet, 8 - len % 8);
1235
1236         /* Test check bytes. */
1237         if (len != buffer_len(&active_state->incoming_packet))
1238                 packet_disconnect("packet_read_poll1: len %d != buffer_len %d.",
1239                     len, buffer_len(&active_state->incoming_packet));
1240
1241         cp = (u_char *)buffer_ptr(&active_state->incoming_packet) + len - 4;
1242         stored_checksum = get_u32(cp);
1243         if (checksum != stored_checksum)
1244                 packet_disconnect("Corrupted check bytes on input.");
1245         buffer_consume_end(&active_state->incoming_packet, 4);
1246
1247         if (active_state->packet_compression) {
1248                 buffer_clear(&active_state->compression_buffer);
1249                 buffer_uncompress(&active_state->incoming_packet,
1250                     &active_state->compression_buffer);
1251                 buffer_clear(&active_state->incoming_packet);
1252                 buffer_append(&active_state->incoming_packet,
1253                     buffer_ptr(&active_state->compression_buffer),
1254                     buffer_len(&active_state->compression_buffer));
1255         }
1256         active_state->p_read.packets++;
1257         active_state->p_read.bytes += padded_len + 4;
1258         type = buffer_get_char(&active_state->incoming_packet);
1259         if (type < SSH_MSG_MIN || type > SSH_MSG_MAX)
1260                 packet_disconnect("Invalid ssh1 packet type: %d", type);
1261         return type;
1262 }
1263
1264 static int
1265 packet_read_poll2(u_int32_t *seqnr_p)
1266 {
1267         u_int padlen, need;
1268         u_char *macbuf = NULL, *cp, type;
1269         u_int maclen, authlen = 0, aadlen = 0, block_size;
1270         Enc *enc   = NULL;
1271         Mac *mac   = NULL;
1272         Comp *comp = NULL;
1273
1274         if (active_state->packet_discard)
1275                 return SSH_MSG_NONE;
1276
1277         if (active_state->newkeys[MODE_IN] != NULL) {
1278                 enc  = &active_state->newkeys[MODE_IN]->enc;
1279                 mac  = &active_state->newkeys[MODE_IN]->mac;
1280                 comp = &active_state->newkeys[MODE_IN]->comp;
1281                 /* disable mac for authenticated encryption */
1282                 if ((authlen = cipher_authlen(enc->cipher)) != 0)
1283                         mac = NULL;
1284         }
1285         maclen = mac && mac->enabled ? mac->mac_len : 0;
1286         block_size = enc ? enc->block_size : 8;
1287         aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0;
1288
1289         if (aadlen && active_state->packlen == 0) {
1290                 if (cipher_get_length(&active_state->receive_context,
1291                     &active_state->packlen,
1292                     active_state->p_read.seqnr,
1293                     buffer_ptr(&active_state->input),
1294                     buffer_len(&active_state->input)) != 0)
1295                         return SSH_MSG_NONE;
1296                 if (active_state->packlen < 1 + 4 ||
1297                     active_state->packlen > PACKET_MAX_SIZE) {
1298 #ifdef PACKET_DEBUG
1299                         buffer_dump(&active_state->input);
1300 #endif
1301                         logit("Bad packet length %u.", active_state->packlen);
1302                         packet_disconnect("Packet corrupt");
1303                 }
1304                 buffer_clear(&active_state->incoming_packet);
1305         } else if (active_state->packlen == 0) {
1306                 /*
1307                  * check if input size is less than the cipher block size,
1308                  * decrypt first block and extract length of incoming packet
1309                  */
1310                 if (buffer_len(&active_state->input) < block_size)
1311                         return SSH_MSG_NONE;
1312                 buffer_clear(&active_state->incoming_packet);
1313                 cp = buffer_append_space(&active_state->incoming_packet,
1314                     block_size);
1315                 if (cipher_crypt(&active_state->receive_context,
1316                     active_state->p_read.seqnr, cp,
1317                     buffer_ptr(&active_state->input), block_size, 0, 0) != 0)
1318                         fatal("Decryption integrity check failed");
1319                 cp = buffer_ptr(&active_state->incoming_packet);
1320
1321                 active_state->packlen = get_u32(cp);
1322                 if (active_state->packlen < 1 + 4 ||
1323                     active_state->packlen > PACKET_MAX_SIZE) {
1324 #ifdef PACKET_DEBUG
1325                         buffer_dump(&active_state->incoming_packet);
1326 #endif
1327                         logit("Bad packet length %u.", active_state->packlen);
1328                         packet_start_discard(enc, mac, active_state->packlen,
1329                             PACKET_MAX_SIZE);
1330                         return SSH_MSG_NONE;
1331                 }
1332                 buffer_consume(&active_state->input, block_size);
1333         }
1334         DBG(debug("input: packet len %u", active_state->packlen+4));
1335         if (aadlen) {
1336                 /* only the payload is encrypted */
1337                 need = active_state->packlen;
1338         } else {
1339                 /*
1340                  * the payload size and the payload are encrypted, but we
1341                  * have a partial packet of block_size bytes
1342                  */
1343                 need = 4 + active_state->packlen - block_size;
1344         }
1345         DBG(debug("partial packet: block %d, need %d, maclen %d, authlen %d,"
1346             " aadlen %d", block_size, need, maclen, authlen, aadlen));
1347         if (need % block_size != 0) {
1348                 logit("padding error: need %d block %d mod %d",
1349                     need, block_size, need % block_size);
1350                 packet_start_discard(enc, mac, active_state->packlen,
1351                     PACKET_MAX_SIZE - block_size);
1352                 return SSH_MSG_NONE;
1353         }
1354         /*
1355          * check if the entire packet has been received and
1356          * decrypt into incoming_packet:
1357          * 'aadlen' bytes are unencrypted, but authenticated.
1358          * 'need' bytes are encrypted, followed by either
1359          * 'authlen' bytes of authentication tag or
1360          * 'maclen' bytes of message authentication code.
1361          */
1362         if (buffer_len(&active_state->input) < aadlen + need + authlen + maclen)
1363                 return SSH_MSG_NONE;
1364 #ifdef PACKET_DEBUG
1365         fprintf(stderr, "read_poll enc/full: ");
1366         buffer_dump(&active_state->input);
1367 #endif
1368         /* EtM: compute mac over encrypted input */
1369         if (mac && mac->enabled && mac->etm)
1370                 macbuf = mac_compute(mac, active_state->p_read.seqnr,
1371                     buffer_ptr(&active_state->input), aadlen + need);
1372         cp = buffer_append_space(&active_state->incoming_packet, aadlen + need);
1373         if (cipher_crypt(&active_state->receive_context,
1374             active_state->p_read.seqnr, cp,
1375             buffer_ptr(&active_state->input), need, aadlen, authlen) != 0)
1376                 fatal("Decryption integrity check failed");
1377         buffer_consume(&active_state->input, aadlen + need + authlen);
1378         /*
1379          * compute MAC over seqnr and packet,
1380          * increment sequence number for incoming packet
1381          */
1382         if (mac && mac->enabled) {
1383                 if (!mac->etm)
1384                         macbuf = mac_compute(mac, active_state->p_read.seqnr,
1385                             buffer_ptr(&active_state->incoming_packet),
1386                             buffer_len(&active_state->incoming_packet));
1387                 if (timingsafe_bcmp(macbuf, buffer_ptr(&active_state->input),
1388                     mac->mac_len) != 0) {
1389                         logit("Corrupted MAC on input.");
1390                         if (need > PACKET_MAX_SIZE)
1391                                 fatal("internal error need %d", need);
1392                         packet_start_discard(enc, mac, active_state->packlen,
1393                             PACKET_MAX_SIZE - need);
1394                         return SSH_MSG_NONE;
1395                 }
1396
1397                 DBG(debug("MAC #%d ok", active_state->p_read.seqnr));
1398                 buffer_consume(&active_state->input, mac->mac_len);
1399         }
1400         /* XXX now it's safe to use fatal/packet_disconnect */
1401         if (seqnr_p != NULL)
1402                 *seqnr_p = active_state->p_read.seqnr;
1403         if (++active_state->p_read.seqnr == 0)
1404                 logit("incoming seqnr wraps around");
1405         if (++active_state->p_read.packets == 0)
1406                 if (!(datafellows & SSH_BUG_NOREKEY))
1407                         fatal("XXX too many packets with same key");
1408         active_state->p_read.blocks += (active_state->packlen + 4) / block_size;
1409         active_state->p_read.bytes += active_state->packlen + 4;
1410
1411         /* get padlen */
1412         cp = buffer_ptr(&active_state->incoming_packet);
1413         padlen = cp[4];
1414         DBG(debug("input: padlen %d", padlen));
1415         if (padlen < 4)
1416                 packet_disconnect("Corrupted padlen %d on input.", padlen);
1417
1418         /* skip packet size + padlen, discard padding */
1419         buffer_consume(&active_state->incoming_packet, 4 + 1);
1420         buffer_consume_end(&active_state->incoming_packet, padlen);
1421
1422         DBG(debug("input: len before de-compress %d",
1423             buffer_len(&active_state->incoming_packet)));
1424         if (comp && comp->enabled) {
1425                 buffer_clear(&active_state->compression_buffer);
1426                 buffer_uncompress(&active_state->incoming_packet,
1427                     &active_state->compression_buffer);
1428                 buffer_clear(&active_state->incoming_packet);
1429                 buffer_append(&active_state->incoming_packet,
1430                     buffer_ptr(&active_state->compression_buffer),
1431                     buffer_len(&active_state->compression_buffer));
1432                 DBG(debug("input: len after de-compress %d",
1433                     buffer_len(&active_state->incoming_packet)));
1434         }
1435         /*
1436          * get packet type, implies consume.
1437          * return length of payload (without type field)
1438          */
1439         type = buffer_get_char(&active_state->incoming_packet);
1440         if (type < SSH2_MSG_MIN || type >= SSH2_MSG_LOCAL_MIN)
1441                 packet_disconnect("Invalid ssh2 packet type: %d", type);
1442         if (type == SSH2_MSG_NEWKEYS)
1443                 set_newkeys(MODE_IN);
1444         else if (type == SSH2_MSG_USERAUTH_SUCCESS &&
1445             !active_state->server_side)
1446                 packet_enable_delayed_compress();
1447 #ifdef PACKET_DEBUG
1448         fprintf(stderr, "read/plain[%d]:\r\n", type);
1449         buffer_dump(&active_state->incoming_packet);
1450 #endif
1451         /* reset for next packet */
1452         active_state->packlen = 0;
1453         return type;
1454 }
1455
1456 int
1457 packet_read_poll_seqnr(u_int32_t *seqnr_p)
1458 {
1459         u_int reason, seqnr;
1460         u_char type;
1461         char *msg;
1462
1463         for (;;) {
1464                 if (compat20) {
1465                         type = packet_read_poll2(seqnr_p);
1466                         if (type) {
1467                                 active_state->keep_alive_timeouts = 0;
1468                                 DBG(debug("received packet type %d", type));
1469                         }
1470                         switch (type) {
1471                         case SSH2_MSG_IGNORE:
1472                                 debug3("Received SSH2_MSG_IGNORE");
1473                                 break;
1474                         case SSH2_MSG_DEBUG:
1475                                 packet_get_char();
1476                                 msg = packet_get_string(NULL);
1477                                 debug("Remote: %.900s", msg);
1478                                 free(msg);
1479                                 msg = packet_get_string(NULL);
1480                                 free(msg);
1481                                 break;
1482                         case SSH2_MSG_DISCONNECT:
1483                                 reason = packet_get_int();
1484                                 msg = packet_get_string(NULL);
1485                                 /* Ignore normal client exit notifications */
1486                                 do_log2(active_state->server_side &&
1487                                     reason == SSH2_DISCONNECT_BY_APPLICATION ?
1488                                     SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_ERROR,
1489                                     "Received disconnect from %s: %u: %.400s",
1490                                     get_remote_ipaddr(), reason, msg);
1491                                 free(msg);
1492                                 cleanup_exit(255);
1493                                 break;
1494                         case SSH2_MSG_UNIMPLEMENTED:
1495                                 seqnr = packet_get_int();
1496                                 debug("Received SSH2_MSG_UNIMPLEMENTED for %u",
1497                                     seqnr);
1498                                 break;
1499                         default:
1500                                 return type;
1501                         }
1502                 } else {
1503                         type = packet_read_poll1();
1504                         switch (type) {
1505                         case SSH_MSG_NONE:
1506                                 return SSH_MSG_NONE;
1507                         case SSH_MSG_IGNORE:
1508                                 break;
1509                         case SSH_MSG_DEBUG:
1510                                 msg = packet_get_string(NULL);
1511                                 debug("Remote: %.900s", msg);
1512                                 free(msg);
1513                                 break;
1514                         case SSH_MSG_DISCONNECT:
1515                                 msg = packet_get_string(NULL);
1516                                 logit("Received disconnect from %s: %.400s",
1517                                     get_remote_ipaddr(), msg);
1518                                 cleanup_exit(255);
1519                                 break;
1520                         default:
1521                                 DBG(debug("received packet type %d", type));
1522                                 return type;
1523                         }
1524                 }
1525         }
1526 }
1527
1528 /*
1529  * Buffers the given amount of input characters.  This is intended to be used
1530  * together with packet_read_poll.
1531  */
1532
1533 void
1534 packet_process_incoming(const char *buf, u_int len)
1535 {
1536         if (active_state->packet_discard) {
1537                 active_state->keep_alive_timeouts = 0; /* ?? */
1538                 if (len >= active_state->packet_discard)
1539                         packet_stop_discard();
1540                 active_state->packet_discard -= len;
1541                 return;
1542         }
1543         buffer_append(&active_state->input, buf, len);
1544 }
1545
1546 /* Returns a character from the packet. */
1547
1548 u_int
1549 packet_get_char(void)
1550 {
1551         char ch;
1552
1553         buffer_get(&active_state->incoming_packet, &ch, 1);
1554         return (u_char) ch;
1555 }
1556
1557 /* Returns an integer from the packet data. */
1558
1559 u_int
1560 packet_get_int(void)
1561 {
1562         return buffer_get_int(&active_state->incoming_packet);
1563 }
1564
1565 /* Returns an 64 bit integer from the packet data. */
1566
1567 u_int64_t
1568 packet_get_int64(void)
1569 {
1570         return buffer_get_int64(&active_state->incoming_packet);
1571 }
1572
1573 /*
1574  * Returns an arbitrary precision integer from the packet data.  The integer
1575  * must have been initialized before this call.
1576  */
1577
1578 void
1579 packet_get_bignum(BIGNUM * value)
1580 {
1581         buffer_get_bignum(&active_state->incoming_packet, value);
1582 }
1583
1584 void
1585 packet_get_bignum2(BIGNUM * value)
1586 {
1587         buffer_get_bignum2(&active_state->incoming_packet, value);
1588 }
1589
1590 #ifdef OPENSSL_HAS_ECC
1591 void
1592 packet_get_ecpoint(const EC_GROUP *curve, EC_POINT *point)
1593 {
1594         buffer_get_ecpoint(&active_state->incoming_packet, curve, point);
1595 }
1596 #endif
1597
1598 void *
1599 packet_get_raw(u_int *length_ptr)
1600 {
1601         u_int bytes = buffer_len(&active_state->incoming_packet);
1602
1603         if (length_ptr != NULL)
1604                 *length_ptr = bytes;
1605         return buffer_ptr(&active_state->incoming_packet);
1606 }
1607
1608 int
1609 packet_remaining(void)
1610 {
1611         return buffer_len(&active_state->incoming_packet);
1612 }
1613
1614 /*
1615  * Returns a string from the packet data.  The string is allocated using
1616  * xmalloc; it is the responsibility of the calling program to free it when
1617  * no longer needed.  The length_ptr argument may be NULL, or point to an
1618  * integer into which the length of the string is stored.
1619  */
1620
1621 void *
1622 packet_get_string(u_int *length_ptr)
1623 {
1624         return buffer_get_string(&active_state->incoming_packet, length_ptr);
1625 }
1626
1627 void *
1628 packet_get_string_ptr(u_int *length_ptr)
1629 {
1630         return buffer_get_string_ptr(&active_state->incoming_packet, length_ptr);
1631 }
1632
1633 /* Ensures the returned string has no embedded \0 characters in it. */
1634 char *
1635 packet_get_cstring(u_int *length_ptr)
1636 {
1637         return buffer_get_cstring(&active_state->incoming_packet, length_ptr);
1638 }
1639
1640 /*
1641  * Sends a diagnostic message from the server to the client.  This message
1642  * can be sent at any time (but not while constructing another message). The
1643  * message is printed immediately, but only if the client is being executed
1644  * in verbose mode.  These messages are primarily intended to ease debugging
1645  * authentication problems.   The length of the formatted message must not
1646  * exceed 1024 bytes.  This will automatically call packet_write_wait.
1647  */
1648
1649 void
1650 packet_send_debug(const char *fmt,...)
1651 {
1652         char buf[1024];
1653         va_list args;
1654
1655         if (compat20 && (datafellows & SSH_BUG_DEBUG))
1656                 return;
1657
1658         va_start(args, fmt);
1659         vsnprintf(buf, sizeof(buf), fmt, args);
1660         va_end(args);
1661
1662         if (compat20) {
1663                 packet_start(SSH2_MSG_DEBUG);
1664                 packet_put_char(0);     /* bool: always display */
1665                 packet_put_cstring(buf);
1666                 packet_put_cstring("");
1667         } else {
1668                 packet_start(SSH_MSG_DEBUG);
1669                 packet_put_cstring(buf);
1670         }
1671         packet_send();
1672         packet_write_wait();
1673 }
1674
1675 /*
1676  * Logs the error plus constructs and sends a disconnect packet, closes the
1677  * connection, and exits.  This function never returns. The error message
1678  * should not contain a newline.  The length of the formatted message must
1679  * not exceed 1024 bytes.
1680  */
1681
1682 void
1683 packet_disconnect(const char *fmt,...)
1684 {
1685         char buf[1024];
1686         va_list args;
1687         static int disconnecting = 0;
1688
1689         if (disconnecting)      /* Guard against recursive invocations. */
1690                 fatal("packet_disconnect called recursively.");
1691         disconnecting = 1;
1692
1693         /*
1694          * Format the message.  Note that the caller must make sure the
1695          * message is of limited size.
1696          */
1697         va_start(args, fmt);
1698         vsnprintf(buf, sizeof(buf), fmt, args);
1699         va_end(args);
1700
1701         /* Display the error locally */
1702         logit("Disconnecting: %.100s", buf);
1703
1704         /* Send the disconnect message to the other side, and wait for it to get sent. */
1705         if (compat20) {
1706                 packet_start(SSH2_MSG_DISCONNECT);
1707                 packet_put_int(SSH2_DISCONNECT_PROTOCOL_ERROR);
1708                 packet_put_cstring(buf);
1709                 packet_put_cstring("");
1710         } else {
1711                 packet_start(SSH_MSG_DISCONNECT);
1712                 packet_put_cstring(buf);
1713         }
1714         packet_send();
1715         packet_write_wait();
1716
1717         /* Stop listening for connections. */
1718         channel_close_all();
1719
1720         /* Close the connection. */
1721         packet_close();
1722         cleanup_exit(255);
1723 }
1724
1725 /* Checks if there is any buffered output, and tries to write some of the output. */
1726
1727 void
1728 packet_write_poll(void)
1729 {
1730         int len = buffer_len(&active_state->output);
1731         int cont;
1732
1733         if (len > 0) {
1734                 cont = 0;
1735                 len = roaming_write(active_state->connection_out,
1736                     buffer_ptr(&active_state->output), len, &cont);
1737                 if (len == -1) {
1738                         if (errno == EINTR || errno == EAGAIN ||
1739                             errno == EWOULDBLOCK)
1740                                 return;
1741                         fatal("Write failed: %.100s", strerror(errno));
1742                 }
1743                 if (len == 0 && !cont)
1744                         fatal("Write connection closed");
1745                 buffer_consume(&active_state->output, len);
1746         }
1747 }
1748
1749 /*
1750  * Calls packet_write_poll repeatedly until all pending output data has been
1751  * written.
1752  */
1753
1754 void
1755 packet_write_wait(void)
1756 {
1757         fd_set *setp;
1758         int ret, ms_remain = 0;
1759         struct timeval start, timeout, *timeoutp = NULL;
1760
1761         setp = (fd_set *)xcalloc(howmany(active_state->connection_out + 1,
1762             NFDBITS), sizeof(fd_mask));
1763         packet_write_poll();
1764         while (packet_have_data_to_write()) {
1765                 memset(setp, 0, howmany(active_state->connection_out + 1,
1766                     NFDBITS) * sizeof(fd_mask));
1767                 FD_SET(active_state->connection_out, setp);
1768
1769                 if (active_state->packet_timeout_ms > 0) {
1770                         ms_remain = active_state->packet_timeout_ms;
1771                         timeoutp = &timeout;
1772                 }
1773                 for (;;) {
1774                         if (active_state->packet_timeout_ms != -1) {
1775                                 ms_to_timeval(&timeout, ms_remain);
1776                                 gettimeofday(&start, NULL);
1777                         }
1778                         if ((ret = select(active_state->connection_out + 1,
1779                             NULL, setp, NULL, timeoutp)) >= 0)
1780                                 break;
1781                         if (errno != EAGAIN && errno != EINTR &&
1782                             errno != EWOULDBLOCK)
1783                                 break;
1784                         if (active_state->packet_timeout_ms == -1)
1785                                 continue;
1786                         ms_subtract_diff(&start, &ms_remain);
1787                         if (ms_remain <= 0) {
1788                                 ret = 0;
1789                                 break;
1790                         }
1791                 }
1792                 if (ret == 0) {
1793                         logit("Connection to %.200s timed out while "
1794                             "waiting to write", get_remote_ipaddr());
1795                         cleanup_exit(255);
1796                 }
1797                 packet_write_poll();
1798         }
1799         free(setp);
1800 }
1801
1802 /* Returns true if there is buffered data to write to the connection. */
1803
1804 int
1805 packet_have_data_to_write(void)
1806 {
1807         return buffer_len(&active_state->output) != 0;
1808 }
1809
1810 /* Returns true if there is not too much data to write to the connection. */
1811
1812 int
1813 packet_not_very_much_data_to_write(void)
1814 {
1815         if (active_state->interactive_mode)
1816                 return buffer_len(&active_state->output) < 16384;
1817         else
1818                 return buffer_len(&active_state->output) < 128 * 1024;
1819 }
1820
1821 static void
1822 packet_set_tos(int tos)
1823 {
1824 #ifndef IP_TOS_IS_BROKEN
1825         if (!packet_connection_is_on_socket())
1826                 return;
1827         switch (packet_connection_af()) {
1828 # ifdef IP_TOS
1829         case AF_INET:
1830                 debug3("%s: set IP_TOS 0x%02x", __func__, tos);
1831                 if (setsockopt(active_state->connection_in,
1832                     IPPROTO_IP, IP_TOS, &tos, sizeof(tos)) < 0)
1833                         error("setsockopt IP_TOS %d: %.100s:",
1834                             tos, strerror(errno));
1835                 break;
1836 # endif /* IP_TOS */
1837 # ifdef IPV6_TCLASS
1838         case AF_INET6:
1839                 debug3("%s: set IPV6_TCLASS 0x%02x", __func__, tos);
1840                 if (setsockopt(active_state->connection_in,
1841                     IPPROTO_IPV6, IPV6_TCLASS, &tos, sizeof(tos)) < 0)
1842                         error("setsockopt IPV6_TCLASS %d: %.100s:",
1843                             tos, strerror(errno));
1844                 break;
1845 # endif /* IPV6_TCLASS */
1846         }
1847 #endif /* IP_TOS_IS_BROKEN */
1848 }
1849
1850 /* Informs that the current session is interactive.  Sets IP flags for that. */
1851
1852 void
1853 packet_set_interactive(int interactive, int qos_interactive, int qos_bulk)
1854 {
1855         if (active_state->set_interactive_called)
1856                 return;
1857         active_state->set_interactive_called = 1;
1858
1859         /* Record that we are in interactive mode. */
1860         active_state->interactive_mode = interactive;
1861
1862         /* Only set socket options if using a socket.  */
1863         if (!packet_connection_is_on_socket())
1864                 return;
1865         set_nodelay(active_state->connection_in);
1866         packet_set_tos(interactive ? qos_interactive : qos_bulk);
1867 }
1868
1869 /* Returns true if the current connection is interactive. */
1870
1871 int
1872 packet_is_interactive(void)
1873 {
1874         return active_state->interactive_mode;
1875 }
1876
1877 int
1878 packet_set_maxsize(u_int s)
1879 {
1880         if (active_state->set_maxsize_called) {
1881                 logit("packet_set_maxsize: called twice: old %d new %d",
1882                     active_state->max_packet_size, s);
1883                 return -1;
1884         }
1885         if (s < 4 * 1024 || s > 1024 * 1024) {
1886                 logit("packet_set_maxsize: bad size %d", s);
1887                 return -1;
1888         }
1889         active_state->set_maxsize_called = 1;
1890         debug("packet_set_maxsize: setting to %d", s);
1891         active_state->max_packet_size = s;
1892         return s;
1893 }
1894
1895 int
1896 packet_inc_alive_timeouts(void)
1897 {
1898         return ++active_state->keep_alive_timeouts;
1899 }
1900
1901 void
1902 packet_set_alive_timeouts(int ka)
1903 {
1904         active_state->keep_alive_timeouts = ka;
1905 }
1906
1907 u_int
1908 packet_get_maxsize(void)
1909 {
1910         return active_state->max_packet_size;
1911 }
1912
1913 /* roundup current message to pad bytes */
1914 void
1915 packet_add_padding(u_char pad)
1916 {
1917         active_state->extra_pad = pad;
1918 }
1919
1920 /*
1921  * 9.2.  Ignored Data Message
1922  *
1923  *   byte      SSH_MSG_IGNORE
1924  *   string    data
1925  *
1926  * All implementations MUST understand (and ignore) this message at any
1927  * time (after receiving the protocol version). No implementation is
1928  * required to send them. This message can be used as an additional
1929  * protection measure against advanced traffic analysis techniques.
1930  */
1931 void
1932 packet_send_ignore(int nbytes)
1933 {
1934         u_int32_t rnd = 0;
1935         int i;
1936
1937         packet_start(compat20 ? SSH2_MSG_IGNORE : SSH_MSG_IGNORE);
1938         packet_put_int(nbytes);
1939         for (i = 0; i < nbytes; i++) {
1940                 if (i % 4 == 0)
1941                         rnd = arc4random();
1942                 packet_put_char((u_char)rnd & 0xff);
1943                 rnd >>= 8;
1944         }
1945 }
1946
1947 #ifdef  NONE_CIPHER_ENABLED
1948 void
1949 packet_request_rekeying(void)
1950 {
1951         rekey_requested = 1;
1952 }
1953 #endif
1954
1955 #define MAX_PACKETS     (1U<<31)
1956 int
1957 packet_need_rekeying(void)
1958 {
1959         if (datafellows & SSH_BUG_NOREKEY)
1960                 return 0;
1961 #ifdef  NONE_CIPHER_ENABLED
1962         if (rekey_requested == 1) {
1963                 rekey_requested = 0;
1964                 return 1;
1965         }
1966 #endif
1967         return
1968             (active_state->p_send.packets > MAX_PACKETS) ||
1969             (active_state->p_read.packets > MAX_PACKETS) ||
1970             (active_state->max_blocks_out &&
1971                 (active_state->p_send.blocks > active_state->max_blocks_out)) ||
1972             (active_state->max_blocks_in &&
1973                 (active_state->p_read.blocks > active_state->max_blocks_in)) ||
1974             (active_state->rekey_interval != 0 && active_state->rekey_time +
1975                  active_state->rekey_interval <= monotime());
1976 }
1977
1978 void
1979 packet_set_rekey_limits(u_int32_t bytes, time_t seconds)
1980 {
1981         debug3("rekey after %lld bytes, %d seconds", (long long)bytes,
1982             (int)seconds);
1983         active_state->rekey_limit = bytes;
1984         active_state->rekey_interval = seconds;
1985         /*
1986          * We set the time here so that in post-auth privsep slave we count
1987          * from the completion of the authentication.
1988          */
1989         active_state->rekey_time = monotime();
1990 }
1991
1992 time_t
1993 packet_get_rekey_timeout(void)
1994 {
1995         time_t seconds;
1996
1997         seconds = active_state->rekey_time + active_state->rekey_interval -
1998             monotime();
1999         return (seconds <= 0 ? 1 : seconds);
2000 }
2001
2002 void
2003 packet_set_server(void)
2004 {
2005         active_state->server_side = 1;
2006 }
2007
2008 void
2009 packet_set_authenticated(void)
2010 {
2011         active_state->after_authentication = 1;
2012 }
2013
2014 void *
2015 packet_get_input(void)
2016 {
2017         return (void *)&active_state->input;
2018 }
2019
2020 void *
2021 packet_get_output(void)
2022 {
2023         return (void *)&active_state->output;
2024 }
2025
2026 void *
2027 packet_get_newkeys(int mode)
2028 {
2029         return (void *)active_state->newkeys[mode];
2030 }
2031
2032 /*
2033  * Save the state for the real connection, and use a separate state when
2034  * resuming a suspended connection.
2035  */
2036 void
2037 packet_backup_state(void)
2038 {
2039         struct session_state *tmp;
2040
2041         close(active_state->connection_in);
2042         active_state->connection_in = -1;
2043         close(active_state->connection_out);
2044         active_state->connection_out = -1;
2045         if (backup_state)
2046                 tmp = backup_state;
2047         else
2048                 tmp = alloc_session_state();
2049         backup_state = active_state;
2050         active_state = tmp;
2051 }
2052
2053 /*
2054  * Swap in the old state when resuming a connecion.
2055  */
2056 void
2057 packet_restore_state(void)
2058 {
2059         struct session_state *tmp;
2060         void *buf;
2061         u_int len;
2062
2063         tmp = backup_state;
2064         backup_state = active_state;
2065         active_state = tmp;
2066         active_state->connection_in = backup_state->connection_in;
2067         backup_state->connection_in = -1;
2068         active_state->connection_out = backup_state->connection_out;
2069         backup_state->connection_out = -1;
2070         len = buffer_len(&backup_state->input);
2071         if (len > 0) {
2072                 buf = buffer_ptr(&backup_state->input);
2073                 buffer_append(&active_state->input, buf, len);
2074                 buffer_clear(&backup_state->input);
2075                 add_recv_bytes(len);
2076         }
2077 }
2078
2079 #ifdef  NONE_CIPHER_ENABLED
2080 int
2081 packet_get_authentication_state(void)
2082 {
2083         return (active_state->after_authentication);
2084 }
2085 #endif