crypto/openssh/packet.c

   1 /* $OpenBSD: packet.c,v 1.243 2016/10/11 21:47:45 djm Exp $ */
   2 /*
   3  * Author: Tatu Ylonen <ylo@cs.hut.fi>
   4  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
   5  *                    All rights reserved
   6  * This file contains code implementing the packet protocol and communication
   7  * with the other side.  This same code is used both on client and server side.
   8  *
   9  * As far as I am concerned, the code I have written for this software
  10  * can be used freely for any purpose.  Any derived versions of this
  11  * software must be clearly marked as such, and if the derived work is
  12  * incompatible with the protocol description in the RFC file, it must be
  13  * called by a name other than "ssh" or "Secure Shell".
  14  *
  15  *
  16  * SSH2 packet format added by Markus Friedl.
  17  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
  18  *
  19  * Redistribution and use in source and binary forms, with or without
  20  * modification, are permitted provided that the following conditions
  21  * are met:
  22  * 1. Redistributions of source code must retain the above copyright
  23  *    notice, this list of conditions and the following disclaimer.
  24  * 2. Redistributions in binary form must reproduce the above copyright
  25  *    notice, this list of conditions and the following disclaimer in the
  26  *    documentation and/or other materials provided with the distribution.
  27  *
  28  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  29  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  30  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  31  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  32  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  33  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  34  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  35  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  36  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  37  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  38  */
  39
  40 #include "includes.h"
  41 __RCSID("$FreeBSD$");
  42
  43 #include <sys/types.h>
  44 #include "openbsd-compat/sys-queue.h"
  45 #include <sys/socket.h>
  46 #ifdef HAVE_SYS_TIME_H
  47 # include <sys/time.h>
  48 #endif
  49
  50 #include <netinet/in.h>
  51 #include <netinet/ip.h>
  52 #include <arpa/inet.h>
  53
  54 #include <errno.h>
  55 #include <netdb.h>
  56 #include <stdarg.h>
  57 #include <stdio.h>
  58 #include <stdlib.h>
  59 #include <string.h>
  60 #include <unistd.h>
  61 #include <limits.h>
  62 #include <signal.h>
  63 #include <time.h>
  64
  65 #include <zlib.h>
  66
  67 #include "buffer.h"     /* typedefs XXX */
  68 #include "key.h"        /* typedefs XXX */
  69
  70 #include "xmalloc.h"
  71 #include "crc32.h"
  72 #include "deattack.h"
  73 #include "compat.h"
  74 #include "ssh1.h"
  75 #include "ssh2.h"
  76 #include "cipher.h"
  77 #include "sshkey.h"
  78 #include "kex.h"
  79 #include "digest.h"
  80 #include "mac.h"
  81 #include "log.h"
  82 #include "canohost.h"
  83 #include "misc.h"
  84 #include "channels.h"
  85 #include "ssh.h"
  86 #include "packet.h"
  87 #include "ssherr.h"
  88 #include "sshbuf.h"
  89 #include "blacklist_client.h"
  90
  91 #ifdef PACKET_DEBUG
  92 #define DBG(x) x
  93 #else
  94 #define DBG(x)
  95 #endif
  96
  97 #define PACKET_MAX_SIZE (256 * 1024)
  98
  99 struct packet_state {
 100         u_int32_t seqnr;
 101         u_int32_t packets;
 102         u_int64_t blocks;
 103         u_int64_t bytes;
 104 };
 105
 106 struct packet {
 107         TAILQ_ENTRY(packet) next;
 108         u_char type;
 109         struct sshbuf *payload;
 110 };
 111
 112 struct session_state {
 113         /*
 114          * This variable contains the file descriptors used for
 115          * communicating with the other side.  connection_in is used for
 116          * reading; connection_out for writing.  These can be the same
 117          * descriptor, in which case it is assumed to be a socket.
 118          */
 119         int connection_in;
 120         int connection_out;
 121
 122         /* Protocol flags for the remote side. */
 123         u_int remote_protocol_flags;
 124
 125         /* Encryption context for receiving data.  Only used for decryption. */
 126         struct sshcipher_ctx *receive_context;
 127
 128         /* Encryption context for sending data.  Only used for encryption. */
 129         struct sshcipher_ctx *send_context;
 130
 131         /* Buffer for raw input data from the socket. */
 132         struct sshbuf *input;
 133
 134         /* Buffer for raw output data going to the socket. */
 135         struct sshbuf *output;
 136
 137         /* Buffer for the partial outgoing packet being constructed. */
 138         struct sshbuf *outgoing_packet;
 139
 140         /* Buffer for the incoming packet currently being processed. */
 141         struct sshbuf *incoming_packet;
 142
 143         /* Scratch buffer for packet compression/decompression. */
 144         struct sshbuf *compression_buffer;
 145
 146         /* Incoming/outgoing compression dictionaries */
 147         z_stream compression_in_stream;
 148         z_stream compression_out_stream;
 149         int compression_in_started;
 150         int compression_out_started;
 151         int compression_in_failures;
 152         int compression_out_failures;
 153
 154         /*
 155          * Flag indicating whether packet compression/decompression is
 156          * enabled.
 157          */
 158         int packet_compression;
 159
 160         /* default maximum packet size */
 161         u_int max_packet_size;
 162
 163         /* Flag indicating whether this module has been initialized. */
 164         int initialized;
 165
 166         /* Set to true if the connection is interactive. */
 167         int interactive_mode;
 168
 169         /* Set to true if we are the server side. */
 170         int server_side;
 171
 172         /* Set to true if we are authenticated. */
 173         int after_authentication;
 174
 175         int keep_alive_timeouts;
 176
 177         /* The maximum time that we will wait to send or receive a packet */
 178         int packet_timeout_ms;
 179
 180         /* Session key information for Encryption and MAC */
 181         struct newkeys *newkeys[MODE_MAX];
 182         struct packet_state p_read, p_send;
 183
 184         /* Volume-based rekeying */
 185         u_int64_t max_blocks_in, max_blocks_out, rekey_limit;
 186
 187         /* Time-based rekeying */
 188         u_int32_t rekey_interval;       /* how often in seconds */
 189         time_t rekey_time;      /* time of last rekeying */
 190
 191         /* Session key for protocol v1 */
 192         u_char ssh1_key[SSH_SESSION_KEY_LENGTH];
 193         u_int ssh1_keylen;
 194
 195         /* roundup current message to extra_pad bytes */
 196         u_char extra_pad;
 197
 198         /* XXX discard incoming data after MAC error */
 199         u_int packet_discard;
 200         size_t packet_discard_mac_already;
 201         struct sshmac *packet_discard_mac;
 202
 203         /* Used in packet_read_poll2() */
 204         u_int packlen;
 205
 206         /* Used in packet_send2 */
 207         int rekeying;
 208
 209         /* Used in ssh_packet_send_mux() */
 210         int mux;
 211
 212         /* Used in packet_set_interactive */
 213         int set_interactive_called;
 214
 215         /* Used in packet_set_maxsize */
 216         int set_maxsize_called;
 217
 218         /* One-off warning about weak ciphers */
 219         int cipher_warning_done;
 220
 221         /* SSH1 CRC compensation attack detector */
 222         struct deattack_ctx deattack;
 223
 224         /* Hook for fuzzing inbound packets */
 225         ssh_packet_hook_fn *hook_in;
 226         void *hook_in_ctx;
 227
 228         TAILQ_HEAD(, packet) outgoing;
 229 };
 230
 231 struct ssh *
 232 ssh_alloc_session_state(void)
 233 {
 234         struct ssh *ssh = NULL;
 235         struct session_state *state = NULL;
 236
 237         if ((ssh = calloc(1, sizeof(*ssh))) == NULL ||
 238             (state = calloc(1, sizeof(*state))) == NULL ||
 239             (state->input = sshbuf_new()) == NULL ||
 240             (state->output = sshbuf_new()) == NULL ||
 241             (state->outgoing_packet = sshbuf_new()) == NULL ||
 242             (state->incoming_packet = sshbuf_new()) == NULL)
 243                 goto fail;
 244         TAILQ_INIT(&state->outgoing);
 245         TAILQ_INIT(&ssh->private_keys);
 246         TAILQ_INIT(&ssh->public_keys);
 247         state->connection_in = -1;
 248         state->connection_out = -1;
 249         state->max_packet_size = 32768;
 250         state->packet_timeout_ms = -1;
 251         state->p_send.packets = state->p_read.packets = 0;
 252         state->initialized = 1;
 253         /*
 254          * ssh_packet_send2() needs to queue packets until
 255          * we've done the initial key exchange.
 256          */
 257         state->rekeying = 1;
 258         ssh->state = state;
 259         return ssh;
 260  fail:
 261         if (state) {
 262                 sshbuf_free(state->input);
 263                 sshbuf_free(state->output);
 264                 sshbuf_free(state->incoming_packet);
 265                 sshbuf_free(state->outgoing_packet);
 266                 free(state);
 267         }
 268         free(ssh);
 269         return NULL;
 270 }
 271
 272 void
 273 ssh_packet_set_input_hook(struct ssh *ssh, ssh_packet_hook_fn *hook, void *ctx)
 274 {
 275         ssh->state->hook_in = hook;
 276         ssh->state->hook_in_ctx = ctx;
 277 }
 278
 279 /* Returns nonzero if rekeying is in progress */
 280 int
 281 ssh_packet_is_rekeying(struct ssh *ssh)
 282 {
 283         return compat20 &&
 284             (ssh->state->rekeying || (ssh->kex != NULL && ssh->kex->done == 0));
 285 }
 286
 287 /*
 288  * Sets the descriptors used for communication.  Disables encryption until
 289  * packet_set_encryption_key is called.
 290  */
 291 struct ssh *
 292 ssh_packet_set_connection(struct ssh *ssh, int fd_in, int fd_out)
 293 {
 294         struct session_state *state;
 295         const struct sshcipher *none = cipher_by_name("none");
 296         int r;
 297
 298         if (none == NULL) {
 299                 error("%s: cannot load cipher 'none'", __func__);
 300                 return NULL;
 301         }
 302         if (ssh == NULL)
 303                 ssh = ssh_alloc_session_state();
 304         if (ssh == NULL) {
 305                 error("%s: cound not allocate state", __func__);
 306                 return NULL;
 307         }
 308         state = ssh->state;
 309         state->connection_in = fd_in;
 310         state->connection_out = fd_out;
 311         if ((r = cipher_init(&state->send_context, none,
 312             (const u_char *)"", 0, NULL, 0, CIPHER_ENCRYPT)) != 0 ||
 313             (r = cipher_init(&state->receive_context, none,
 314             (const u_char *)"", 0, NULL, 0, CIPHER_DECRYPT)) != 0) {
 315                 error("%s: cipher_init failed: %s", __func__, ssh_err(r));
 316                 free(ssh); /* XXX need ssh_free_session_state? */
 317                 return NULL;
 318         }
 319         state->newkeys[MODE_IN] = state->newkeys[MODE_OUT] = NULL;
 320         deattack_init(&state->deattack);
 321         /*
 322          * Cache the IP address of the remote connection for use in error
 323          * messages that might be generated after the connection has closed.
 324          */
 325         (void)ssh_remote_ipaddr(ssh);
 326         return ssh;
 327 }
 328
 329 void
 330 ssh_packet_set_timeout(struct ssh *ssh, int timeout, int count)
 331 {
 332         struct session_state *state = ssh->state;
 333
 334         if (timeout <= 0 || count <= 0) {
 335                 state->packet_timeout_ms = -1;
 336                 return;
 337         }
 338         if ((INT_MAX / 1000) / count < timeout)
 339                 state->packet_timeout_ms = INT_MAX;
 340         else
 341                 state->packet_timeout_ms = timeout * count * 1000;
 342 }
 343
 344 void
 345 ssh_packet_set_mux(struct ssh *ssh)
 346 {
 347         ssh->state->mux = 1;
 348         ssh->state->rekeying = 0;
 349 }
 350
 351 int
 352 ssh_packet_get_mux(struct ssh *ssh)
 353 {
 354         return ssh->state->mux;
 355 }
 356
 357 int
 358 ssh_packet_stop_discard(struct ssh *ssh)
 359 {
 360         struct session_state *state = ssh->state;
 361         int r;
 362
 363         if (state->packet_discard_mac) {
 364                 char buf[1024];
 365                 size_t dlen = PACKET_MAX_SIZE;
 366
 367                 if (dlen > state->packet_discard_mac_already)
 368                         dlen -= state->packet_discard_mac_already;
 369                 memset(buf, 'a', sizeof(buf));
 370                 while (sshbuf_len(state->incoming_packet) < dlen)
 371                         if ((r = sshbuf_put(state->incoming_packet, buf,
 372                             sizeof(buf))) != 0)
 373                                 return r;
 374                 (void) mac_compute(state->packet_discard_mac,
 375                     state->p_read.seqnr,
 376                     sshbuf_ptr(state->incoming_packet), dlen,
 377                     NULL, 0);
 378         }
 379         logit("Finished discarding for %.200s port %d",
 380             ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
 381         return SSH_ERR_MAC_INVALID;
 382 }
 383
 384 static int
 385 ssh_packet_start_discard(struct ssh *ssh, struct sshenc *enc,
 386     struct sshmac *mac, size_t mac_already, u_int discard)
 387 {
 388         struct session_state *state = ssh->state;
 389         int r;
 390
 391         if (enc == NULL || !cipher_is_cbc(enc->cipher) || (mac && mac->etm)) {
 392                 if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0)
 393                         return r;
 394                 return SSH_ERR_MAC_INVALID;
 395         }
 396         /*
 397          * Record number of bytes over which the mac has already
 398          * been computed in order to minimize timing attacks.
 399          */
 400         if (mac && mac->enabled) {
 401                 state->packet_discard_mac = mac;
 402                 state->packet_discard_mac_already = mac_already;
 403         }
 404         if (sshbuf_len(state->input) >= discard)
 405                 return ssh_packet_stop_discard(ssh);
 406         state->packet_discard = discard - sshbuf_len(state->input);
 407         return 0;
 408 }
 409
 410 /* Returns 1 if remote host is connected via socket, 0 if not. */
 411
 412 int
 413 ssh_packet_connection_is_on_socket(struct ssh *ssh)
 414 {
 415         struct session_state *state = ssh->state;
 416         struct sockaddr_storage from, to;
 417         socklen_t fromlen, tolen;
 418
 419         if (state->connection_in == -1 || state->connection_out == -1)
 420                 return 0;
 421
 422         /* filedescriptors in and out are the same, so it's a socket */
 423         if (state->connection_in == state->connection_out)
 424                 return 1;
 425         fromlen = sizeof(from);
 426         memset(&from, 0, sizeof(from));
 427         if (getpeername(state->connection_in, (struct sockaddr *)&from,
 428             &fromlen) < 0)
 429                 return 0;
 430         tolen = sizeof(to);
 431         memset(&to, 0, sizeof(to));
 432         if (getpeername(state->connection_out, (struct sockaddr *)&to,
 433             &tolen) < 0)
 434                 return 0;
 435         if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0)
 436                 return 0;
 437         if (from.ss_family != AF_INET && from.ss_family != AF_INET6)
 438                 return 0;
 439         return 1;
 440 }
 441
 442 void
 443 ssh_packet_get_bytes(struct ssh *ssh, u_int64_t *ibytes, u_int64_t *obytes)
 444 {
 445         if (ibytes)
 446                 *ibytes = ssh->state->p_read.bytes;
 447         if (obytes)
 448                 *obytes = ssh->state->p_send.bytes;
 449 }
 450
 451 int
 452 ssh_packet_connection_af(struct ssh *ssh)
 453 {
 454         struct sockaddr_storage to;
 455         socklen_t tolen = sizeof(to);
 456
 457         memset(&to, 0, sizeof(to));
 458         if (getsockname(ssh->state->connection_out, (struct sockaddr *)&to,
 459             &tolen) < 0)
 460                 return 0;
 461 #ifdef IPV4_IN_IPV6
 462         if (to.ss_family == AF_INET6 &&
 463             IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&to)->sin6_addr))
 464                 return AF_INET;
 465 #endif
 466         return to.ss_family;
 467 }
 468
 469 /* Sets the connection into non-blocking mode. */
 470
 471 void
 472 ssh_packet_set_nonblocking(struct ssh *ssh)
 473 {
 474         /* Set the socket into non-blocking mode. */
 475         set_nonblock(ssh->state->connection_in);
 476
 477         if (ssh->state->connection_out != ssh->state->connection_in)
 478                 set_nonblock(ssh->state->connection_out);
 479 }
 480
 481 /* Returns the socket used for reading. */
 482
 483 int
 484 ssh_packet_get_connection_in(struct ssh *ssh)
 485 {
 486         return ssh->state->connection_in;
 487 }
 488
 489 /* Returns the descriptor used for writing. */
 490
 491 int
 492 ssh_packet_get_connection_out(struct ssh *ssh)
 493 {
 494         return ssh->state->connection_out;
 495 }
 496
 497 /*
 498  * Returns the IP-address of the remote host as a string.  The returned
 499  * string must not be freed.
 500  */
 501
 502 const char *
 503 ssh_remote_ipaddr(struct ssh *ssh)
 504 {
 505         const int sock = ssh->state->connection_in;
 506
 507         /* Check whether we have cached the ipaddr. */
 508         if (ssh->remote_ipaddr == NULL) {
 509                 if (ssh_packet_connection_is_on_socket(ssh)) {
 510                         ssh->remote_ipaddr = get_peer_ipaddr(sock);
 511                         ssh->remote_port = get_peer_port(sock);
 512                         ssh->local_ipaddr = get_local_ipaddr(sock);
 513                         ssh->local_port = get_local_port(sock);
 514                 } else {
 515                         ssh->remote_ipaddr = strdup("UNKNOWN");
 516                         ssh->remote_port = 65535;
 517                         ssh->local_ipaddr = strdup("UNKNOWN");
 518                         ssh->local_port = 65535;
 519                 }
 520         }
 521         return ssh->remote_ipaddr;
 522 }
 523
 524 /* Returns the port number of the remote host. */
 525
 526 int
 527 ssh_remote_port(struct ssh *ssh)
 528 {
 529         (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */
 530         return ssh->remote_port;
 531 }
 532
 533 /*
 534  * Returns the IP-address of the local host as a string.  The returned
 535  * string must not be freed.
 536  */
 537
 538 const char *
 539 ssh_local_ipaddr(struct ssh *ssh)
 540 {
 541         (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */
 542         return ssh->local_ipaddr;
 543 }
 544
 545 /* Returns the port number of the local host. */
 546
 547 int
 548 ssh_local_port(struct ssh *ssh)
 549 {
 550         (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */
 551         return ssh->local_port;
 552 }
 553
 554 /* Closes the connection and clears and frees internal data structures. */
 555
 556 void
 557 ssh_packet_close(struct ssh *ssh)
 558 {
 559         struct session_state *state = ssh->state;
 560         u_int mode;
 561
 562         if (!state->initialized)
 563                 return;
 564         state->initialized = 0;
 565         if (state->connection_in == state->connection_out) {
 566                 shutdown(state->connection_out, SHUT_RDWR);
 567                 close(state->connection_out);
 568         } else {
 569                 close(state->connection_in);
 570                 close(state->connection_out);
 571         }
 572         sshbuf_free(state->input);
 573         sshbuf_free(state->output);
 574         sshbuf_free(state->outgoing_packet);
 575         sshbuf_free(state->incoming_packet);
 576         for (mode = 0; mode < MODE_MAX; mode++)
 577                 kex_free_newkeys(state->newkeys[mode]);
 578         if (state->compression_buffer) {
 579                 sshbuf_free(state->compression_buffer);
 580                 if (state->compression_out_started) {
 581                         z_streamp stream = &state->compression_out_stream;
 582                         debug("compress outgoing: "
 583                             "raw data %llu, compressed %llu, factor %.2f",
 584                                 (unsigned long long)stream->total_in,
 585                                 (unsigned long long)stream->total_out,
 586                                 stream->total_in == 0 ? 0.0 :
 587                                 (double) stream->total_out / stream->total_in);
 588                         if (state->compression_out_failures == 0)
 589                                 deflateEnd(stream);
 590                 }
 591                 if (state->compression_in_started) {
 592                         z_streamp stream = &state->compression_out_stream;
 593                         debug("compress incoming: "
 594                             "raw data %llu, compressed %llu, factor %.2f",
 595                             (unsigned long long)stream->total_out,
 596                             (unsigned long long)stream->total_in,
 597                             stream->total_out == 0 ? 0.0 :
 598                             (double) stream->total_in / stream->total_out);
 599                         if (state->compression_in_failures == 0)
 600                                 inflateEnd(stream);
 601                 }
 602         }
 603         cipher_free(state->send_context);
 604         cipher_free(state->receive_context);
 605         state->send_context = state->receive_context = NULL;
 606         free(ssh->remote_ipaddr);
 607         ssh->remote_ipaddr = NULL;
 608         free(ssh->state);
 609         ssh->state = NULL;
 610 }
 611
 612 /* Sets remote side protocol flags. */
 613
 614 void
 615 ssh_packet_set_protocol_flags(struct ssh *ssh, u_int protocol_flags)
 616 {
 617         ssh->state->remote_protocol_flags = protocol_flags;
 618 }
 619
 620 /* Returns the remote protocol flags set earlier by the above function. */
 621
 622 u_int
 623 ssh_packet_get_protocol_flags(struct ssh *ssh)
 624 {
 625         return ssh->state->remote_protocol_flags;
 626 }
 627
 628 /*
 629  * Starts packet compression from the next packet on in both directions.
 630  * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip.
 631  */
 632
 633 static int
 634 ssh_packet_init_compression(struct ssh *ssh)
 635 {
 636         if (!ssh->state->compression_buffer &&
 637            ((ssh->state->compression_buffer = sshbuf_new()) == NULL))
 638                 return SSH_ERR_ALLOC_FAIL;
 639         return 0;
 640 }
 641
 642 static int
 643 start_compression_out(struct ssh *ssh, int level)
 644 {
 645         if (level < 1 || level > 9)
 646                 return SSH_ERR_INVALID_ARGUMENT;
 647         debug("Enabling compression at level %d.", level);
 648         if (ssh->state->compression_out_started == 1)
 649                 deflateEnd(&ssh->state->compression_out_stream);
 650         switch (deflateInit(&ssh->state->compression_out_stream, level)) {
 651         case Z_OK:
 652                 ssh->state->compression_out_started = 1;
 653                 break;
 654         case Z_MEM_ERROR:
 655                 return SSH_ERR_ALLOC_FAIL;
 656         default:
 657                 return SSH_ERR_INTERNAL_ERROR;
 658         }
 659         return 0;
 660 }
 661
 662 static int
 663 start_compression_in(struct ssh *ssh)
 664 {
 665         if (ssh->state->compression_in_started == 1)
 666                 inflateEnd(&ssh->state->compression_in_stream);
 667         switch (inflateInit(&ssh->state->compression_in_stream)) {
 668         case Z_OK:
 669                 ssh->state->compression_in_started = 1;
 670                 break;
 671         case Z_MEM_ERROR:
 672                 return SSH_ERR_ALLOC_FAIL;
 673         default:
 674                 return SSH_ERR_INTERNAL_ERROR;
 675         }
 676         return 0;
 677 }
 678
 679 int
 680 ssh_packet_start_compression(struct ssh *ssh, int level)
 681 {
 682         int r;
 683
 684         if (ssh->state->packet_compression && !compat20)
 685                 return SSH_ERR_INTERNAL_ERROR;
 686         ssh->state->packet_compression = 1;
 687         if ((r = ssh_packet_init_compression(ssh)) != 0 ||
 688             (r = start_compression_in(ssh)) != 0 ||
 689             (r = start_compression_out(ssh, level)) != 0)
 690                 return r;
 691         return 0;
 692 }
 693
 694 /* XXX remove need for separate compression buffer */
 695 static int
 696 compress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out)
 697 {
 698         u_char buf[4096];
 699         int r, status;
 700
 701         if (ssh->state->compression_out_started != 1)
 702                 return SSH_ERR_INTERNAL_ERROR;
 703
 704         /* This case is not handled below. */
 705         if (sshbuf_len(in) == 0)
 706                 return 0;
 707
 708         /* Input is the contents of the input buffer. */
 709         if ((ssh->state->compression_out_stream.next_in =
 710             sshbuf_mutable_ptr(in)) == NULL)
 711                 return SSH_ERR_INTERNAL_ERROR;
 712         ssh->state->compression_out_stream.avail_in = sshbuf_len(in);
 713
 714         /* Loop compressing until deflate() returns with avail_out != 0. */
 715         do {
 716                 /* Set up fixed-size output buffer. */
 717                 ssh->state->compression_out_stream.next_out = buf;
 718                 ssh->state->compression_out_stream.avail_out = sizeof(buf);
 719
 720                 /* Compress as much data into the buffer as possible. */
 721                 status = deflate(&ssh->state->compression_out_stream,
 722                     Z_PARTIAL_FLUSH);
 723                 switch (status) {
 724                 case Z_MEM_ERROR:
 725                         return SSH_ERR_ALLOC_FAIL;
 726                 case Z_OK:
 727                         /* Append compressed data to output_buffer. */
 728                         if ((r = sshbuf_put(out, buf, sizeof(buf) -
 729                             ssh->state->compression_out_stream.avail_out)) != 0)
 730                                 return r;
 731                         break;
 732                 case Z_STREAM_ERROR:
 733                 default:
 734                         ssh->state->compression_out_failures++;
 735                         return SSH_ERR_INVALID_FORMAT;
 736                 }
 737         } while (ssh->state->compression_out_stream.avail_out == 0);
 738         return 0;
 739 }
 740
 741 static int
 742 uncompress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out)
 743 {
 744         u_char buf[4096];
 745         int r, status;
 746
 747         if (ssh->state->compression_in_started != 1)
 748                 return SSH_ERR_INTERNAL_ERROR;
 749
 750         if ((ssh->state->compression_in_stream.next_in =
 751             sshbuf_mutable_ptr(in)) == NULL)
 752                 return SSH_ERR_INTERNAL_ERROR;
 753         ssh->state->compression_in_stream.avail_in = sshbuf_len(in);
 754
 755         for (;;) {
 756                 /* Set up fixed-size output buffer. */
 757                 ssh->state->compression_in_stream.next_out = buf;
 758                 ssh->state->compression_in_stream.avail_out = sizeof(buf);
 759
 760                 status = inflate(&ssh->state->compression_in_stream,
 761                     Z_PARTIAL_FLUSH);
 762                 switch (status) {
 763                 case Z_OK:
 764                         if ((r = sshbuf_put(out, buf, sizeof(buf) -
 765                             ssh->state->compression_in_stream.avail_out)) != 0)
 766                                 return r;
 767                         break;
 768                 case Z_BUF_ERROR:
 769                         /*
 770                          * Comments in zlib.h say that we should keep calling
 771                          * inflate() until we get an error.  This appears to
 772                          * be the error that we get.
 773                          */
 774                         return 0;
 775                 case Z_DATA_ERROR:
 776                         return SSH_ERR_INVALID_FORMAT;
 777                 case Z_MEM_ERROR:
 778                         return SSH_ERR_ALLOC_FAIL;
 779                 case Z_STREAM_ERROR:
 780                 default:
 781                         ssh->state->compression_in_failures++;
 782                         return SSH_ERR_INTERNAL_ERROR;
 783                 }
 784         }
 785         /* NOTREACHED */
 786 }
 787
 788 /*
 789  * Causes any further packets to be encrypted using the given key.  The same
 790  * key is used for both sending and reception.  However, both directions are
 791  * encrypted independently of each other.
 792  */
 793
 794 void
 795 ssh_packet_set_encryption_key(struct ssh *ssh, const u_char *key, u_int keylen, int number)
 796 {
 797 #ifndef WITH_SSH1
 798         fatal("no SSH protocol 1 support");
 799 #else /* WITH_SSH1 */
 800         struct session_state *state = ssh->state;
 801         const struct sshcipher *cipher = cipher_by_number(number);
 802         int r;
 803         const char *wmsg;
 804
 805         if (cipher == NULL)
 806                 fatal("%s: unknown cipher number %d", __func__, number);
 807         if (keylen < 20)
 808                 fatal("%s: keylen too small: %d", __func__, keylen);
 809         if (keylen > SSH_SESSION_KEY_LENGTH)
 810                 fatal("%s: keylen too big: %d", __func__, keylen);
 811         memcpy(state->ssh1_key, key, keylen);
 812         state->ssh1_keylen = keylen;
 813         if ((r = cipher_init(&state->send_context, cipher, key, keylen,
 814             NULL, 0, CIPHER_ENCRYPT)) != 0 ||
 815             (r = cipher_init(&state->receive_context, cipher, key, keylen,
 816             NULL, 0, CIPHER_DECRYPT) != 0))
 817                 fatal("%s: cipher_init failed: %s", __func__, ssh_err(r));
 818         if (!state->cipher_warning_done &&
 819             ((wmsg = cipher_warning_message(state->send_context)) != NULL ||
 820             (wmsg = cipher_warning_message(state->send_context)) != NULL)) {
 821                 error("Warning: %s", wmsg);
 822                 state->cipher_warning_done = 1;
 823         }
 824 #endif /* WITH_SSH1 */
 825 }
 826
 827 /*
 828  * Finalizes and sends the packet.  If the encryption key has been set,
 829  * encrypts the packet before sending.
 830  */
 831
 832 int
 833 ssh_packet_send1(struct ssh *ssh)
 834 {
 835         struct session_state *state = ssh->state;
 836         u_char buf[8], *cp;
 837         int r, padding, len;
 838         u_int checksum;
 839
 840         /*
 841          * If using packet compression, compress the payload of the outgoing
 842          * packet.
 843          */
 844         if (state->packet_compression) {
 845                 sshbuf_reset(state->compression_buffer);
 846                 /* Skip padding. */
 847                 if ((r = sshbuf_consume(state->outgoing_packet, 8)) != 0)
 848                         goto out;
 849                 /* padding */
 850                 if ((r = sshbuf_put(state->compression_buffer,
 851                     "\0\0\0\0\0\0\0\0", 8)) != 0)
 852                         goto out;
 853                 if ((r = compress_buffer(ssh, state->outgoing_packet,
 854                     state->compression_buffer)) != 0)
 855                         goto out;
 856                 sshbuf_reset(state->outgoing_packet);
 857                 if ((r = sshbuf_putb(state->outgoing_packet,
 858                     state->compression_buffer)) != 0)
 859                         goto out;
 860         }
 861         /* Compute packet length without padding (add checksum, remove padding). */
 862         len = sshbuf_len(state->outgoing_packet) + 4 - 8;
 863
 864         /* Insert padding. Initialized to zero in packet_start1() */
 865         padding = 8 - len % 8;
 866         if (!cipher_ctx_is_plaintext(state->send_context)) {
 867                 cp = sshbuf_mutable_ptr(state->outgoing_packet);
 868                 if (cp == NULL) {
 869                         r = SSH_ERR_INTERNAL_ERROR;
 870                         goto out;
 871                 }
 872                 arc4random_buf(cp + 8 - padding, padding);
 873         }
 874         if ((r = sshbuf_consume(state->outgoing_packet, 8 - padding)) != 0)
 875                 goto out;
 876
 877         /* Add check bytes. */
 878         checksum = ssh_crc32(sshbuf_ptr(state->outgoing_packet),
 879             sshbuf_len(state->outgoing_packet));
 880         POKE_U32(buf, checksum);
 881         if ((r = sshbuf_put(state->outgoing_packet, buf, 4)) != 0)
 882                 goto out;
 883
 884 #ifdef PACKET_DEBUG
 885         fprintf(stderr, "packet_send plain: ");
 886         sshbuf_dump(state->outgoing_packet, stderr);
 887 #endif
 888
 889         /* Append to output. */
 890         POKE_U32(buf, len);
 891         if ((r = sshbuf_put(state->output, buf, 4)) != 0)
 892                 goto out;
 893         if ((r = sshbuf_reserve(state->output,
 894             sshbuf_len(state->outgoing_packet), &cp)) != 0)
 895                 goto out;
 896         if ((r = cipher_crypt(state->send_context, 0, cp,
 897             sshbuf_ptr(state->outgoing_packet),
 898             sshbuf_len(state->outgoing_packet), 0, 0)) != 0)
 899                 goto out;
 900
 901 #ifdef PACKET_DEBUG
 902         fprintf(stderr, "encrypted: ");
 903         sshbuf_dump(state->output, stderr);
 904 #endif
 905         state->p_send.packets++;
 906         state->p_send.bytes += len +
 907             sshbuf_len(state->outgoing_packet);
 908         sshbuf_reset(state->outgoing_packet);
 909
 910         /*
 911          * Note that the packet is now only buffered in output.  It won't be
 912          * actually sent until ssh_packet_write_wait or ssh_packet_write_poll
 913          * is called.
 914          */
 915         r = 0;
 916  out:
 917         return r;
 918 }
 919
 920 int
 921 ssh_set_newkeys(struct ssh *ssh, int mode)
 922 {
 923         struct session_state *state = ssh->state;
 924         struct sshenc *enc;
 925         struct sshmac *mac;
 926         struct sshcomp *comp;
 927         struct sshcipher_ctx **ccp;
 928         struct packet_state *ps;
 929         u_int64_t *max_blocks;
 930         const char *wmsg, *dir;
 931         int r, crypt_type;
 932
 933         debug2("set_newkeys: mode %d", mode);
 934
 935         if (mode == MODE_OUT) {
 936                 dir = "output";
 937                 ccp = &state->send_context;
 938                 crypt_type = CIPHER_ENCRYPT;
 939                 ps = &state->p_send;
 940                 max_blocks = &state->max_blocks_out;
 941         } else {
 942                 dir = "input";
 943                 ccp = &state->receive_context;
 944                 crypt_type = CIPHER_DECRYPT;
 945                 ps = &state->p_read;
 946                 max_blocks = &state->max_blocks_in;
 947         }
 948         if (state->newkeys[mode] != NULL) {
 949                 debug("%s: rekeying after %llu %s blocks"
 950                     " (%llu bytes total)", __func__,
 951                     (unsigned long long)ps->blocks, dir,
 952                     (unsigned long long)ps->bytes);
 953                 cipher_free(*ccp);
 954                 *ccp = NULL;
 955                 enc  = &state->newkeys[mode]->enc;
 956                 mac  = &state->newkeys[mode]->mac;
 957                 comp = &state->newkeys[mode]->comp;
 958                 mac_clear(mac);
 959                 explicit_bzero(enc->iv,  enc->iv_len);
 960                 explicit_bzero(enc->key, enc->key_len);
 961                 explicit_bzero(mac->key, mac->key_len);
 962                 free(enc->name);
 963                 free(enc->iv);
 964                 free(enc->key);
 965                 free(mac->name);
 966                 free(mac->key);
 967                 free(comp->name);
 968                 free(state->newkeys[mode]);
 969         }
 970         /* note that both bytes and the seqnr are not reset */
 971         ps->packets = ps->blocks = 0;
 972         /* move newkeys from kex to state */
 973         if ((state->newkeys[mode] = ssh->kex->newkeys[mode]) == NULL)
 974                 return SSH_ERR_INTERNAL_ERROR;
 975         ssh->kex->newkeys[mode] = NULL;
 976         enc  = &state->newkeys[mode]->enc;
 977         mac  = &state->newkeys[mode]->mac;
 978         comp = &state->newkeys[mode]->comp;
 979         if (cipher_authlen(enc->cipher) == 0) {
 980                 if ((r = mac_init(mac)) != 0)
 981                         return r;
 982         }
 983         mac->enabled = 1;
 984         DBG(debug("cipher_init_context: %d", mode));
 985         if ((r = cipher_init(ccp, enc->cipher, enc->key, enc->key_len,
 986             enc->iv, enc->iv_len, crypt_type)) != 0)
 987                 return r;
 988         if (!state->cipher_warning_done &&
 989             (wmsg = cipher_warning_message(*ccp)) != NULL) {
 990                 error("Warning: %s", wmsg);
 991                 state->cipher_warning_done = 1;
 992         }
 993         /* Deleting the keys does not gain extra security */
 994         /* explicit_bzero(enc->iv,  enc->block_size);
 995            explicit_bzero(enc->key, enc->key_len);
 996            explicit_bzero(mac->key, mac->key_len); */
 997         if ((comp->type == COMP_ZLIB ||
 998             (comp->type == COMP_DELAYED &&
 999              state->after_authentication)) && comp->enabled == 0) {
1000                 if ((r = ssh_packet_init_compression(ssh)) < 0)
1001                         return r;
1002                 if (mode == MODE_OUT) {
1003                         if ((r = start_compression_out(ssh, 6)) != 0)
1004                                 return r;
1005                 } else {
1006                         if ((r = start_compression_in(ssh)) != 0)
1007                                 return r;
1008                 }
1009                 comp->enabled = 1;
1010         }
1011         /*
1012          * The 2^(blocksize*2) limit is too expensive for 3DES,
1013          * blowfish, etc, so enforce a 1GB limit for small blocksizes.
1014          */
1015         if (enc->block_size >= 16)
1016                 *max_blocks = (u_int64_t)1 << (enc->block_size*2);
1017         else
1018                 *max_blocks = ((u_int64_t)1 << 30) / enc->block_size;
1019         if (state->rekey_limit)
1020                 *max_blocks = MINIMUM(*max_blocks,
1021                     state->rekey_limit / enc->block_size);
1022         debug("rekey after %llu blocks", (unsigned long long)*max_blocks);
1023         return 0;
1024 }
1025
1026 #define MAX_PACKETS     (1U<<31)
1027 static int
1028 ssh_packet_need_rekeying(struct ssh *ssh, u_int outbound_packet_len)
1029 {
1030         struct session_state *state = ssh->state;
1031         u_int32_t out_blocks;
1032
1033         /* XXX client can't cope with rekeying pre-auth */
1034         if (!state->after_authentication)
1035                 return 0;
1036
1037         /* Haven't keyed yet or KEX in progress. */
1038         if (ssh->kex == NULL || ssh_packet_is_rekeying(ssh))
1039                 return 0;
1040
1041         /* Peer can't rekey */
1042         if (ssh->compat & SSH_BUG_NOREKEY)
1043                 return 0;
1044
1045         /*
1046          * Permit one packet in or out per rekey - this allows us to
1047          * make progress when rekey limits are very small.
1048          */
1049         if (state->p_send.packets == 0 && state->p_read.packets == 0)
1050                 return 0;
1051
1052         /* Time-based rekeying */
1053         if (state->rekey_interval != 0 &&
1054             state->rekey_time + state->rekey_interval <= monotime())
1055                 return 1;
1056
1057         /* Always rekey when MAX_PACKETS sent in either direction */
1058         if (state->p_send.packets > MAX_PACKETS ||
1059             state->p_read.packets > MAX_PACKETS)
1060                 return 1;
1061
1062         /* Rekey after (cipher-specific) maxiumum blocks */
1063         out_blocks = ROUNDUP(outbound_packet_len,
1064             state->newkeys[MODE_OUT]->enc.block_size);
1065         return (state->max_blocks_out &&
1066             (state->p_send.blocks + out_blocks > state->max_blocks_out)) ||
1067             (state->max_blocks_in &&
1068             (state->p_read.blocks > state->max_blocks_in));
1069 }
1070
1071 /*
1072  * Delayed compression for SSH2 is enabled after authentication:
1073  * This happens on the server side after a SSH2_MSG_USERAUTH_SUCCESS is sent,
1074  * and on the client side after a SSH2_MSG_USERAUTH_SUCCESS is received.
1075  */
1076 static int
1077 ssh_packet_enable_delayed_compress(struct ssh *ssh)
1078 {
1079         struct session_state *state = ssh->state;
1080         struct sshcomp *comp = NULL;
1081         int r, mode;
1082
1083         /*
1084          * Remember that we are past the authentication step, so rekeying
1085          * with COMP_DELAYED will turn on compression immediately.
1086          */
1087         state->after_authentication = 1;
1088         for (mode = 0; mode < MODE_MAX; mode++) {
1089                 /* protocol error: USERAUTH_SUCCESS received before NEWKEYS */
1090                 if (state->newkeys[mode] == NULL)
1091                         continue;
1092                 comp = &state->newkeys[mode]->comp;
1093                 if (comp && !comp->enabled && comp->type == COMP_DELAYED) {
1094                         if ((r = ssh_packet_init_compression(ssh)) != 0)
1095                                 return r;
1096                         if (mode == MODE_OUT) {
1097                                 if ((r = start_compression_out(ssh, 6)) != 0)
1098                                         return r;
1099                         } else {
1100                                 if ((r = start_compression_in(ssh)) != 0)
1101                                         return r;
1102                         }
1103                         comp->enabled = 1;
1104                 }
1105         }
1106         return 0;
1107 }
1108
1109 /* Used to mute debug logging for noisy packet types */
1110 int
1111 ssh_packet_log_type(u_char type)
1112 {
1113         switch (type) {
1114         case SSH2_MSG_CHANNEL_DATA:
1115         case SSH2_MSG_CHANNEL_EXTENDED_DATA:
1116         case SSH2_MSG_CHANNEL_WINDOW_ADJUST:
1117                 return 0;
1118         default:
1119                 return 1;
1120         }
1121 }
1122
1123 /*
1124  * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue)
1125  */
1126 int
1127 ssh_packet_send2_wrapped(struct ssh *ssh)
1128 {
1129         struct session_state *state = ssh->state;
1130         u_char type, *cp, macbuf[SSH_DIGEST_MAX_LENGTH];
1131         u_char tmp, padlen, pad = 0;
1132         u_int authlen = 0, aadlen = 0;
1133         u_int len;
1134         struct sshenc *enc   = NULL;
1135         struct sshmac *mac   = NULL;
1136         struct sshcomp *comp = NULL;
1137         int r, block_size;
1138
1139         if (state->newkeys[MODE_OUT] != NULL) {
1140                 enc  = &state->newkeys[MODE_OUT]->enc;
1141                 mac  = &state->newkeys[MODE_OUT]->mac;
1142                 comp = &state->newkeys[MODE_OUT]->comp;
1143                 /* disable mac for authenticated encryption */
1144                 if ((authlen = cipher_authlen(enc->cipher)) != 0)
1145                         mac = NULL;
1146         }
1147         block_size = enc ? enc->block_size : 8;
1148         aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0;
1149
1150         type = (sshbuf_ptr(state->outgoing_packet))[5];
1151         if (ssh_packet_log_type(type))
1152                 debug3("send packet: type %u", type);
1153 #ifdef PACKET_DEBUG
1154         fprintf(stderr, "plain:     ");
1155         sshbuf_dump(state->outgoing_packet, stderr);
1156 #endif
1157
1158         if (comp && comp->enabled) {
1159                 len = sshbuf_len(state->outgoing_packet);
1160                 /* skip header, compress only payload */
1161                 if ((r = sshbuf_consume(state->outgoing_packet, 5)) != 0)
1162                         goto out;
1163                 sshbuf_reset(state->compression_buffer);
1164                 if ((r = compress_buffer(ssh, state->outgoing_packet,
1165                     state->compression_buffer)) != 0)
1166                         goto out;
1167                 sshbuf_reset(state->outgoing_packet);
1168                 if ((r = sshbuf_put(state->outgoing_packet,
1169                     "\0\0\0\0\0", 5)) != 0 ||
1170                     (r = sshbuf_putb(state->outgoing_packet,
1171                     state->compression_buffer)) != 0)
1172                         goto out;
1173                 DBG(debug("compression: raw %d compressed %zd", len,
1174                     sshbuf_len(state->outgoing_packet)));
1175         }
1176
1177         /* sizeof (packet_len + pad_len + payload) */
1178         len = sshbuf_len(state->outgoing_packet);
1179
1180         /*
1181          * calc size of padding, alloc space, get random data,
1182          * minimum padding is 4 bytes
1183          */
1184         len -= aadlen; /* packet length is not encrypted for EtM modes */
1185         padlen = block_size - (len % block_size);
1186         if (padlen < 4)
1187                 padlen += block_size;
1188         if (state->extra_pad) {
1189                 tmp = state->extra_pad;
1190                 state->extra_pad =
1191                     ROUNDUP(state->extra_pad, block_size);
1192                 /* check if roundup overflowed */
1193                 if (state->extra_pad < tmp)
1194                         return SSH_ERR_INVALID_ARGUMENT;
1195                 tmp = (len + padlen) % state->extra_pad;
1196                 /* Check whether pad calculation below will underflow */
1197                 if (tmp > state->extra_pad)
1198                         return SSH_ERR_INVALID_ARGUMENT;
1199                 pad = state->extra_pad - tmp;
1200                 DBG(debug3("%s: adding %d (len %d padlen %d extra_pad %d)",
1201                     __func__, pad, len, padlen, state->extra_pad));
1202                 tmp = padlen;
1203                 padlen += pad;
1204                 /* Check whether padlen calculation overflowed */
1205                 if (padlen < tmp)
1206                         return SSH_ERR_INVALID_ARGUMENT; /* overflow */
1207                 state->extra_pad = 0;
1208         }
1209         if ((r = sshbuf_reserve(state->outgoing_packet, padlen, &cp)) != 0)
1210                 goto out;
1211         if (enc && !cipher_ctx_is_plaintext(state->send_context)) {
1212                 /* random padding */
1213                 arc4random_buf(cp, padlen);
1214         } else {
1215                 /* clear padding */
1216                 explicit_bzero(cp, padlen);
1217         }
1218         /* sizeof (packet_len + pad_len + payload + padding) */
1219         len = sshbuf_len(state->outgoing_packet);
1220         cp = sshbuf_mutable_ptr(state->outgoing_packet);
1221         if (cp == NULL) {
1222                 r = SSH_ERR_INTERNAL_ERROR;
1223                 goto out;
1224         }
1225         /* packet_length includes payload, padding and padding length field */
1226         POKE_U32(cp, len - 4);
1227         cp[4] = padlen;
1228         DBG(debug("send: len %d (includes padlen %d, aadlen %d)",
1229             len, padlen, aadlen));
1230
1231         /* compute MAC over seqnr and packet(length fields, payload, padding) */
1232         if (mac && mac->enabled && !mac->etm) {
1233                 if ((r = mac_compute(mac, state->p_send.seqnr,
1234                     sshbuf_ptr(state->outgoing_packet), len,
1235                     macbuf, sizeof(macbuf))) != 0)
1236                         goto out;
1237                 DBG(debug("done calc MAC out #%d", state->p_send.seqnr));
1238         }
1239         /* encrypt packet and append to output buffer. */
1240         if ((r = sshbuf_reserve(state->output,
1241             sshbuf_len(state->outgoing_packet) + authlen, &cp)) != 0)
1242                 goto out;
1243         if ((r = cipher_crypt(state->send_context, state->p_send.seqnr, cp,
1244             sshbuf_ptr(state->outgoing_packet),
1245             len - aadlen, aadlen, authlen)) != 0)
1246                 goto out;
1247         /* append unencrypted MAC */
1248         if (mac && mac->enabled) {
1249                 if (mac->etm) {
1250                         /* EtM: compute mac over aadlen + cipher text */
1251                         if ((r = mac_compute(mac, state->p_send.seqnr,
1252                             cp, len, macbuf, sizeof(macbuf))) != 0)
1253                                 goto out;
1254                         DBG(debug("done calc MAC(EtM) out #%d",
1255                             state->p_send.seqnr));
1256                 }
1257                 if ((r = sshbuf_put(state->output, macbuf, mac->mac_len)) != 0)
1258                         goto out;
1259         }
1260 #ifdef PACKET_DEBUG
1261         fprintf(stderr, "encrypted: ");
1262         sshbuf_dump(state->output, stderr);
1263 #endif
1264         /* increment sequence number for outgoing packets */
1265         if (++state->p_send.seqnr == 0)
1266                 logit("outgoing seqnr wraps around");
1267         if (++state->p_send.packets == 0)
1268                 if (!(ssh->compat & SSH_BUG_NOREKEY))
1269                         return SSH_ERR_NEED_REKEY;
1270         state->p_send.blocks += len / block_size;
1271         state->p_send.bytes += len;
1272         sshbuf_reset(state->outgoing_packet);
1273
1274         if (type == SSH2_MSG_NEWKEYS)
1275                 r = ssh_set_newkeys(ssh, MODE_OUT);
1276         else if (type == SSH2_MSG_USERAUTH_SUCCESS && state->server_side)
1277                 r = ssh_packet_enable_delayed_compress(ssh);
1278         else
1279                 r = 0;
1280  out:
1281         return r;
1282 }
1283
1284 /* returns non-zero if the specified packet type is usec by KEX */
1285 static int
1286 ssh_packet_type_is_kex(u_char type)
1287 {
1288         return
1289             type >= SSH2_MSG_TRANSPORT_MIN &&
1290             type <= SSH2_MSG_TRANSPORT_MAX &&
1291             type != SSH2_MSG_SERVICE_REQUEST &&
1292             type != SSH2_MSG_SERVICE_ACCEPT &&
1293             type != SSH2_MSG_EXT_INFO;
1294 }
1295
1296 int
1297 ssh_packet_send2(struct ssh *ssh)
1298 {
1299         struct session_state *state = ssh->state;
1300         struct packet *p;
1301         u_char type;
1302         int r, need_rekey;
1303
1304         if (sshbuf_len(state->outgoing_packet) < 6)
1305                 return SSH_ERR_INTERNAL_ERROR;
1306         type = sshbuf_ptr(state->outgoing_packet)[5];
1307         need_rekey = !ssh_packet_type_is_kex(type) &&
1308             ssh_packet_need_rekeying(ssh, sshbuf_len(state->outgoing_packet));
1309
1310         /*
1311          * During rekeying we can only send key exchange messages.
1312          * Queue everything else.
1313          */
1314         if ((need_rekey || state->rekeying) && !ssh_packet_type_is_kex(type)) {
1315                 if (need_rekey)
1316                         debug3("%s: rekex triggered", __func__);
1317                 debug("enqueue packet: %u", type);
1318                 p = calloc(1, sizeof(*p));
1319                 if (p == NULL)
1320                         return SSH_ERR_ALLOC_FAIL;
1321                 p->type = type;
1322                 p->payload = state->outgoing_packet;
1323                 TAILQ_INSERT_TAIL(&state->outgoing, p, next);
1324                 state->outgoing_packet = sshbuf_new();
1325                 if (state->outgoing_packet == NULL)
1326                         return SSH_ERR_ALLOC_FAIL;
1327                 if (need_rekey) {
1328                         /*
1329                          * This packet triggered a rekey, so send the
1330                          * KEXINIT now.
1331                          * NB. reenters this function via kex_start_rekex().
1332                          */
1333                         return kex_start_rekex(ssh);
1334                 }
1335                 return 0;
1336         }
1337
1338         /* rekeying starts with sending KEXINIT */
1339         if (type == SSH2_MSG_KEXINIT)
1340                 state->rekeying = 1;
1341
1342         if ((r = ssh_packet_send2_wrapped(ssh)) != 0)
1343                 return r;
1344
1345         /* after a NEWKEYS message we can send the complete queue */
1346         if (type == SSH2_MSG_NEWKEYS) {
1347                 state->rekeying = 0;
1348                 state->rekey_time = monotime();
1349                 while ((p = TAILQ_FIRST(&state->outgoing))) {
1350                         type = p->type;
1351                         /*
1352                          * If this packet triggers a rekex, then skip the
1353                          * remaining packets in the queue for now.
1354                          * NB. re-enters this function via kex_start_rekex.
1355                          */
1356                         if (ssh_packet_need_rekeying(ssh,
1357                             sshbuf_len(p->payload))) {
1358                                 debug3("%s: queued packet triggered rekex",
1359                                     __func__);
1360                                 return kex_start_rekex(ssh);
1361                         }
1362                         debug("dequeue packet: %u", type);
1363                         sshbuf_free(state->outgoing_packet);
1364                         state->outgoing_packet = p->payload;
1365                         TAILQ_REMOVE(&state->outgoing, p, next);
1366                         memset(p, 0, sizeof(*p));
1367                         free(p);
1368                         if ((r = ssh_packet_send2_wrapped(ssh)) != 0)
1369                                 return r;
1370                 }
1371         }
1372         return 0;
1373 }
1374
1375 /*
1376  * Waits until a packet has been received, and returns its type.  Note that
1377  * no other data is processed until this returns, so this function should not
1378  * be used during the interactive session.
1379  */
1380
1381 int
1382 ssh_packet_read_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
1383 {
1384         struct session_state *state = ssh->state;
1385         int len, r, ms_remain;
1386         fd_set *setp;
1387         char buf[8192];
1388         struct timeval timeout, start, *timeoutp = NULL;
1389
1390         DBG(debug("packet_read()"));
1391
1392         setp = calloc(howmany(state->connection_in + 1,
1393             NFDBITS), sizeof(fd_mask));
1394         if (setp == NULL)
1395                 return SSH_ERR_ALLOC_FAIL;
1396
1397         /*
1398          * Since we are blocking, ensure that all written packets have
1399          * been sent.
1400          */
1401         if ((r = ssh_packet_write_wait(ssh)) != 0)
1402                 goto out;
1403
1404         /* Stay in the loop until we have received a complete packet. */
1405         for (;;) {
1406                 /* Try to read a packet from the buffer. */
1407                 r = ssh_packet_read_poll_seqnr(ssh, typep, seqnr_p);
1408                 if (r != 0)
1409                         break;
1410                 if (!compat20 && (
1411                     *typep == SSH_SMSG_SUCCESS
1412                     || *typep == SSH_SMSG_FAILURE
1413                     || *typep == SSH_CMSG_EOF
1414                     || *typep == SSH_CMSG_EXIT_CONFIRMATION))
1415                         if ((r = sshpkt_get_end(ssh)) != 0)
1416                                 break;
1417                 /* If we got a packet, return it. */
1418                 if (*typep != SSH_MSG_NONE)
1419                         break;
1420                 /*
1421                  * Otherwise, wait for some data to arrive, add it to the
1422                  * buffer, and try again.
1423                  */
1424                 memset(setp, 0, howmany(state->connection_in + 1,
1425                     NFDBITS) * sizeof(fd_mask));
1426                 FD_SET(state->connection_in, setp);
1427
1428                 if (state->packet_timeout_ms > 0) {
1429                         ms_remain = state->packet_timeout_ms;
1430                         timeoutp = &timeout;
1431                 }
1432                 /* Wait for some data to arrive. */
1433                 for (;;) {
1434                         if (state->packet_timeout_ms != -1) {
1435                                 ms_to_timeval(&timeout, ms_remain);
1436                                 gettimeofday(&start, NULL);
1437                         }
1438                         if ((r = select(state->connection_in + 1, setp,
1439                             NULL, NULL, timeoutp)) >= 0)
1440                                 break;
1441                         if (errno != EAGAIN && errno != EINTR &&
1442                             errno != EWOULDBLOCK)
1443                                 break;
1444                         if (state->packet_timeout_ms == -1)
1445                                 continue;
1446                         ms_subtract_diff(&start, &ms_remain);
1447                         if (ms_remain <= 0) {
1448                                 r = 0;
1449                                 break;
1450                         }
1451                 }
1452                 if (r == 0)
1453                         return SSH_ERR_CONN_TIMEOUT;
1454                 /* Read data from the socket. */
1455                 len = read(state->connection_in, buf, sizeof(buf));
1456                 if (len == 0) {
1457                         r = SSH_ERR_CONN_CLOSED;
1458                         goto out;
1459                 }
1460                 if (len < 0) {
1461                         r = SSH_ERR_SYSTEM_ERROR;
1462                         goto out;
1463                 }
1464
1465                 /* Append it to the buffer. */
1466                 if ((r = ssh_packet_process_incoming(ssh, buf, len)) != 0)
1467                         goto out;
1468         }
1469  out:
1470         free(setp);
1471         return r;
1472 }
1473
1474 int
1475 ssh_packet_read(struct ssh *ssh)
1476 {
1477         u_char type;
1478         int r;
1479
1480         if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0)
1481                 fatal("%s: %s", __func__, ssh_err(r));
1482         return type;
1483 }
1484
1485 /*
1486  * Waits until a packet has been received, verifies that its type matches
1487  * that given, and gives a fatal error and exits if there is a mismatch.
1488  */
1489
1490 int
1491 ssh_packet_read_expect(struct ssh *ssh, u_int expected_type)
1492 {
1493         int r;
1494         u_char type;
1495
1496         if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0)
1497                 return r;
1498         if (type != expected_type) {
1499                 if ((r = sshpkt_disconnect(ssh,
1500                     "Protocol error: expected packet type %d, got %d",
1501                     expected_type, type)) != 0)
1502                         return r;
1503                 return SSH_ERR_PROTOCOL_ERROR;
1504         }
1505         return 0;
1506 }
1507
1508 /* Checks if a full packet is available in the data received so far via
1509  * packet_process_incoming.  If so, reads the packet; otherwise returns
1510  * SSH_MSG_NONE.  This does not wait for data from the connection.
1511  *
1512  * SSH_MSG_DISCONNECT is handled specially here.  Also,
1513  * SSH_MSG_IGNORE messages are skipped by this function and are never returned
1514  * to higher levels.
1515  */
1516
1517 int
1518 ssh_packet_read_poll1(struct ssh *ssh, u_char *typep)
1519 {
1520         struct session_state *state = ssh->state;
1521         u_int len, padded_len;
1522         const char *emsg;
1523         const u_char *cp;
1524         u_char *p;
1525         u_int checksum, stored_checksum;
1526         int r;
1527
1528         *typep = SSH_MSG_NONE;
1529
1530         /* Check if input size is less than minimum packet size. */
1531         if (sshbuf_len(state->input) < 4 + 8)
1532                 return 0;
1533         /* Get length of incoming packet. */
1534         len = PEEK_U32(sshbuf_ptr(state->input));
1535         if (len < 1 + 2 + 2 || len > 256 * 1024) {
1536                 if ((r = sshpkt_disconnect(ssh, "Bad packet length %u",
1537                     len)) != 0)
1538                         return r;
1539                 return SSH_ERR_CONN_CORRUPT;
1540         }
1541         padded_len = (len + 8) & ~7;
1542
1543         /* Check if the packet has been entirely received. */
1544         if (sshbuf_len(state->input) < 4 + padded_len)
1545                 return 0;
1546
1547         /* The entire packet is in buffer. */
1548
1549         /* Consume packet length. */
1550         if ((r = sshbuf_consume(state->input, 4)) != 0)
1551                 goto out;
1552
1553         /*
1554          * Cryptographic attack detector for ssh
1555          * (C)1998 CORE-SDI, Buenos Aires Argentina
1556          * Ariel Futoransky(futo@core-sdi.com)
1557          */
1558         if (!cipher_ctx_is_plaintext(state->receive_context)) {
1559                 emsg = NULL;
1560                 switch (detect_attack(&state->deattack,
1561                     sshbuf_ptr(state->input), padded_len)) {
1562                 case DEATTACK_OK:
1563                         break;
1564                 case DEATTACK_DETECTED:
1565                         emsg = "crc32 compensation attack detected";
1566                         break;
1567                 case DEATTACK_DOS_DETECTED:
1568                         emsg = "deattack denial of service detected";
1569                         break;
1570                 default:
1571                         emsg = "deattack error";
1572                         break;
1573                 }
1574                 if (emsg != NULL) {
1575                         error("%s", emsg);
1576                         if ((r = sshpkt_disconnect(ssh, "%s", emsg)) != 0 ||
1577                             (r = ssh_packet_write_wait(ssh)) != 0)
1578                                         return r;
1579                         return SSH_ERR_CONN_CORRUPT;
1580                 }
1581         }
1582
1583         /* Decrypt data to incoming_packet. */
1584         sshbuf_reset(state->incoming_packet);
1585         if ((r = sshbuf_reserve(state->incoming_packet, padded_len, &p)) != 0)
1586                 goto out;
1587         if ((r = cipher_crypt(state->receive_context, 0, p,
1588             sshbuf_ptr(state->input), padded_len, 0, 0)) != 0)
1589                 goto out;
1590
1591         if ((r = sshbuf_consume(state->input, padded_len)) != 0)
1592                 goto out;
1593
1594 #ifdef PACKET_DEBUG
1595         fprintf(stderr, "read_poll plain: ");
1596         sshbuf_dump(state->incoming_packet, stderr);
1597 #endif
1598
1599         /* Compute packet checksum. */
1600         checksum = ssh_crc32(sshbuf_ptr(state->incoming_packet),
1601             sshbuf_len(state->incoming_packet) - 4);
1602
1603         /* Skip padding. */
1604         if ((r = sshbuf_consume(state->incoming_packet, 8 - len % 8)) != 0)
1605                 goto out;
1606
1607         /* Test check bytes. */
1608         if (len != sshbuf_len(state->incoming_packet)) {
1609                 error("%s: len %d != sshbuf_len %zd", __func__,
1610                     len, sshbuf_len(state->incoming_packet));
1611                 if ((r = sshpkt_disconnect(ssh, "invalid packet length")) != 0 ||
1612                     (r = ssh_packet_write_wait(ssh)) != 0)
1613                         return r;
1614                 return SSH_ERR_CONN_CORRUPT;
1615         }
1616
1617         cp = sshbuf_ptr(state->incoming_packet) + len - 4;
1618         stored_checksum = PEEK_U32(cp);
1619         if (checksum != stored_checksum) {
1620                 error("Corrupted check bytes on input");
1621                 if ((r = sshpkt_disconnect(ssh, "connection corrupted")) != 0 ||
1622                     (r = ssh_packet_write_wait(ssh)) != 0)
1623                         return r;
1624                 return SSH_ERR_CONN_CORRUPT;
1625         }
1626         if ((r = sshbuf_consume_end(state->incoming_packet, 4)) < 0)
1627                 goto out;
1628
1629         if (state->packet_compression) {
1630                 sshbuf_reset(state->compression_buffer);
1631                 if ((r = uncompress_buffer(ssh, state->incoming_packet,
1632                     state->compression_buffer)) != 0)
1633                         goto out;
1634                 sshbuf_reset(state->incoming_packet);
1635                 if ((r = sshbuf_putb(state->incoming_packet,
1636                     state->compression_buffer)) != 0)
1637                         goto out;
1638         }
1639         state->p_read.packets++;
1640         state->p_read.bytes += padded_len + 4;
1641         if ((r = sshbuf_get_u8(state->incoming_packet, typep)) != 0)
1642                 goto out;
1643         if (*typep < SSH_MSG_MIN || *typep > SSH_MSG_MAX) {
1644                 error("Invalid ssh1 packet type: %d", *typep);
1645                 if ((r = sshpkt_disconnect(ssh, "invalid packet type")) != 0 ||
1646                     (r = ssh_packet_write_wait(ssh)) != 0)
1647                         return r;
1648                 return SSH_ERR_PROTOCOL_ERROR;
1649         }
1650         r = 0;
1651  out:
1652         return r;
1653 }
1654
1655 static int
1656 ssh_packet_read_poll2_mux(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
1657 {
1658         struct session_state *state = ssh->state;
1659         const u_char *cp;
1660         size_t need;
1661         int r;
1662
1663         if (ssh->kex)
1664                 return SSH_ERR_INTERNAL_ERROR;
1665         *typep = SSH_MSG_NONE;
1666         cp = sshbuf_ptr(state->input);
1667         if (state->packlen == 0) {
1668                 if (sshbuf_len(state->input) < 4 + 1)
1669                         return 0; /* packet is incomplete */
1670                 state->packlen = PEEK_U32(cp);
1671                 if (state->packlen < 4 + 1 ||
1672                     state->packlen > PACKET_MAX_SIZE)
1673                         return SSH_ERR_MESSAGE_INCOMPLETE;
1674         }
1675         need = state->packlen + 4;
1676         if (sshbuf_len(state->input) < need)
1677                 return 0; /* packet is incomplete */
1678         sshbuf_reset(state->incoming_packet);
1679         if ((r = sshbuf_put(state->incoming_packet, cp + 4,
1680             state->packlen)) != 0 ||
1681             (r = sshbuf_consume(state->input, need)) != 0 ||
1682             (r = sshbuf_get_u8(state->incoming_packet, NULL)) != 0 ||
1683             (r = sshbuf_get_u8(state->incoming_packet, typep)) != 0)
1684                 return r;
1685         if (ssh_packet_log_type(*typep))
1686                 debug3("%s: type %u", __func__, *typep);
1687         /* sshbuf_dump(state->incoming_packet, stderr); */
1688         /* reset for next packet */
1689         state->packlen = 0;
1690         return r;
1691 }
1692
1693 int
1694 ssh_packet_read_poll2(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
1695 {
1696         struct session_state *state = ssh->state;
1697         u_int padlen, need;
1698         u_char *cp;
1699         u_int maclen, aadlen = 0, authlen = 0, block_size;
1700         struct sshenc *enc   = NULL;
1701         struct sshmac *mac   = NULL;
1702         struct sshcomp *comp = NULL;
1703         int r;
1704
1705         if (state->mux)
1706                 return ssh_packet_read_poll2_mux(ssh, typep, seqnr_p);
1707
1708         *typep = SSH_MSG_NONE;
1709
1710         if (state->packet_discard)
1711                 return 0;
1712
1713         if (state->newkeys[MODE_IN] != NULL) {
1714                 enc  = &state->newkeys[MODE_IN]->enc;
1715                 mac  = &state->newkeys[MODE_IN]->mac;
1716                 comp = &state->newkeys[MODE_IN]->comp;
1717                 /* disable mac for authenticated encryption */
1718                 if ((authlen = cipher_authlen(enc->cipher)) != 0)
1719                         mac = NULL;
1720         }
1721         maclen = mac && mac->enabled ? mac->mac_len : 0;
1722         block_size = enc ? enc->block_size : 8;
1723         aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0;
1724
1725         if (aadlen && state->packlen == 0) {
1726                 if (cipher_get_length(state->receive_context,
1727                     &state->packlen, state->p_read.seqnr,
1728                     sshbuf_ptr(state->input), sshbuf_len(state->input)) != 0)
1729                         return 0;
1730                 if (state->packlen < 1 + 4 ||
1731                     state->packlen > PACKET_MAX_SIZE) {
1732 #ifdef PACKET_DEBUG
1733                         sshbuf_dump(state->input, stderr);
1734 #endif
1735                         logit("Bad packet length %u.", state->packlen);
1736                         if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0)
1737                                 return r;
1738                         return SSH_ERR_CONN_CORRUPT;
1739                 }
1740                 sshbuf_reset(state->incoming_packet);
1741         } else if (state->packlen == 0) {
1742                 /*
1743                  * check if input size is less than the cipher block size,
1744                  * decrypt first block and extract length of incoming packet
1745                  */
1746                 if (sshbuf_len(state->input) < block_size)
1747                         return 0;
1748                 sshbuf_reset(state->incoming_packet);
1749                 if ((r = sshbuf_reserve(state->incoming_packet, block_size,
1750                     &cp)) != 0)
1751                         goto out;
1752                 if ((r = cipher_crypt(state->receive_context,
1753                     state->p_send.seqnr, cp, sshbuf_ptr(state->input),
1754                     block_size, 0, 0)) != 0)
1755                         goto out;
1756                 state->packlen = PEEK_U32(sshbuf_ptr(state->incoming_packet));
1757                 if (state->packlen < 1 + 4 ||
1758                     state->packlen > PACKET_MAX_SIZE) {
1759 #ifdef PACKET_DEBUG
1760                         fprintf(stderr, "input: \n");
1761                         sshbuf_dump(state->input, stderr);
1762                         fprintf(stderr, "incoming_packet: \n");
1763                         sshbuf_dump(state->incoming_packet, stderr);
1764 #endif
1765                         logit("Bad packet length %u.", state->packlen);
1766                         return ssh_packet_start_discard(ssh, enc, mac, 0,
1767                             PACKET_MAX_SIZE);
1768                 }
1769                 if ((r = sshbuf_consume(state->input, block_size)) != 0)
1770                         goto out;
1771         }
1772         DBG(debug("input: packet len %u", state->packlen+4));
1773
1774         if (aadlen) {
1775                 /* only the payload is encrypted */
1776                 need = state->packlen;
1777         } else {
1778                 /*
1779                  * the payload size and the payload are encrypted, but we
1780                  * have a partial packet of block_size bytes
1781                  */
1782                 need = 4 + state->packlen - block_size;
1783         }
1784         DBG(debug("partial packet: block %d, need %d, maclen %d, authlen %d,"
1785             " aadlen %d", block_size, need, maclen, authlen, aadlen));
1786         if (need % block_size != 0) {
1787                 logit("padding error: need %d block %d mod %d",
1788                     need, block_size, need % block_size);
1789                 return ssh_packet_start_discard(ssh, enc, mac, 0,
1790                     PACKET_MAX_SIZE - block_size);
1791         }
1792         /*
1793          * check if the entire packet has been received and
1794          * decrypt into incoming_packet:
1795          * 'aadlen' bytes are unencrypted, but authenticated.
1796          * 'need' bytes are encrypted, followed by either
1797          * 'authlen' bytes of authentication tag or
1798          * 'maclen' bytes of message authentication code.
1799          */
1800         if (sshbuf_len(state->input) < aadlen + need + authlen + maclen)
1801                 return 0; /* packet is incomplete */
1802 #ifdef PACKET_DEBUG
1803         fprintf(stderr, "read_poll enc/full: ");
1804         sshbuf_dump(state->input, stderr);
1805 #endif
1806         /* EtM: check mac over encrypted input */
1807         if (mac && mac->enabled && mac->etm) {
1808                 if ((r = mac_check(mac, state->p_read.seqnr,
1809                     sshbuf_ptr(state->input), aadlen + need,
1810                     sshbuf_ptr(state->input) + aadlen + need + authlen,
1811                     maclen)) != 0) {
1812                         if (r == SSH_ERR_MAC_INVALID)
1813                                 logit("Corrupted MAC on input.");
1814                         goto out;
1815                 }
1816         }
1817         if ((r = sshbuf_reserve(state->incoming_packet, aadlen + need,
1818             &cp)) != 0)
1819                 goto out;
1820         if ((r = cipher_crypt(state->receive_context, state->p_read.seqnr, cp,
1821             sshbuf_ptr(state->input), need, aadlen, authlen)) != 0)
1822                 goto out;
1823         if ((r = sshbuf_consume(state->input, aadlen + need + authlen)) != 0)
1824                 goto out;
1825         if (mac && mac->enabled) {
1826                 /* Not EtM: check MAC over cleartext */
1827                 if (!mac->etm && (r = mac_check(mac, state->p_read.seqnr,
1828                     sshbuf_ptr(state->incoming_packet),
1829                     sshbuf_len(state->incoming_packet),
1830                     sshbuf_ptr(state->input), maclen)) != 0) {
1831                         if (r != SSH_ERR_MAC_INVALID)
1832                                 goto out;
1833                         logit("Corrupted MAC on input.");
1834                         if (need > PACKET_MAX_SIZE)
1835                                 return SSH_ERR_INTERNAL_ERROR;
1836                         return ssh_packet_start_discard(ssh, enc, mac,
1837                             sshbuf_len(state->incoming_packet),
1838                             PACKET_MAX_SIZE - need);
1839                 }
1840                 /* Remove MAC from input buffer */
1841                 DBG(debug("MAC #%d ok", state->p_read.seqnr));
1842                 if ((r = sshbuf_consume(state->input, mac->mac_len)) != 0)
1843                         goto out;
1844         }
1845         if (seqnr_p != NULL)
1846                 *seqnr_p = state->p_read.seqnr;
1847         if (++state->p_read.seqnr == 0)
1848                 logit("incoming seqnr wraps around");
1849         if (++state->p_read.packets == 0)
1850                 if (!(ssh->compat & SSH_BUG_NOREKEY))
1851                         return SSH_ERR_NEED_REKEY;
1852         state->p_read.blocks += (state->packlen + 4) / block_size;
1853         state->p_read.bytes += state->packlen + 4;
1854
1855         /* get padlen */
1856         padlen = sshbuf_ptr(state->incoming_packet)[4];
1857         DBG(debug("input: padlen %d", padlen));
1858         if (padlen < 4) {
1859                 if ((r = sshpkt_disconnect(ssh,
1860                     "Corrupted padlen %d on input.", padlen)) != 0 ||
1861                     (r = ssh_packet_write_wait(ssh)) != 0)
1862                         return r;
1863                 return SSH_ERR_CONN_CORRUPT;
1864         }
1865
1866         /* skip packet size + padlen, discard padding */
1867         if ((r = sshbuf_consume(state->incoming_packet, 4 + 1)) != 0 ||
1868             ((r = sshbuf_consume_end(state->incoming_packet, padlen)) != 0))
1869                 goto out;
1870
1871         DBG(debug("input: len before de-compress %zd",
1872             sshbuf_len(state->incoming_packet)));
1873         if (comp && comp->enabled) {
1874                 sshbuf_reset(state->compression_buffer);
1875                 if ((r = uncompress_buffer(ssh, state->incoming_packet,
1876                     state->compression_buffer)) != 0)
1877                         goto out;
1878                 sshbuf_reset(state->incoming_packet);
1879                 if ((r = sshbuf_putb(state->incoming_packet,
1880                     state->compression_buffer)) != 0)
1881                         goto out;
1882                 DBG(debug("input: len after de-compress %zd",
1883                     sshbuf_len(state->incoming_packet)));
1884         }
1885         /*
1886          * get packet type, implies consume.
1887          * return length of payload (without type field)
1888          */
1889         if ((r = sshbuf_get_u8(state->incoming_packet, typep)) != 0)
1890                 goto out;
1891         if (ssh_packet_log_type(*typep))
1892                 debug3("receive packet: type %u", *typep);
1893         if (*typep < SSH2_MSG_MIN || *typep >= SSH2_MSG_LOCAL_MIN) {
1894                 if ((r = sshpkt_disconnect(ssh,
1895                     "Invalid ssh2 packet type: %d", *typep)) != 0 ||
1896                     (r = ssh_packet_write_wait(ssh)) != 0)
1897                         return r;
1898                 return SSH_ERR_PROTOCOL_ERROR;
1899         }
1900         if (state->hook_in != NULL &&
1901             (r = state->hook_in(ssh, state->incoming_packet, typep,
1902             state->hook_in_ctx)) != 0)
1903                 return r;
1904         if (*typep == SSH2_MSG_USERAUTH_SUCCESS && !state->server_side)
1905                 r = ssh_packet_enable_delayed_compress(ssh);
1906         else
1907                 r = 0;
1908 #ifdef PACKET_DEBUG
1909         fprintf(stderr, "read/plain[%d]:\r\n", *typep);
1910         sshbuf_dump(state->incoming_packet, stderr);
1911 #endif
1912         /* reset for next packet */
1913         state->packlen = 0;
1914
1915         /* do we need to rekey? */
1916         if (ssh_packet_need_rekeying(ssh, 0)) {
1917                 debug3("%s: rekex triggered", __func__);
1918                 if ((r = kex_start_rekex(ssh)) != 0)
1919                         return r;
1920         }
1921  out:
1922         return r;
1923 }
1924
1925 int
1926 ssh_packet_read_poll_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
1927 {
1928         struct session_state *state = ssh->state;
1929         u_int reason, seqnr;
1930         int r;
1931         u_char *msg;
1932
1933         for (;;) {
1934                 msg = NULL;
1935                 if (compat20) {
1936                         r = ssh_packet_read_poll2(ssh, typep, seqnr_p);
1937                         if (r != 0)
1938                                 return r;
1939                         if (*typep) {
1940                                 state->keep_alive_timeouts = 0;
1941                                 DBG(debug("received packet type %d", *typep));
1942                         }
1943                         switch (*typep) {
1944                         case SSH2_MSG_IGNORE:
1945                                 debug3("Received SSH2_MSG_IGNORE");
1946                                 break;
1947                         case SSH2_MSG_DEBUG:
1948                                 if ((r = sshpkt_get_u8(ssh, NULL)) != 0 ||
1949                                     (r = sshpkt_get_string(ssh, &msg, NULL)) != 0 ||
1950                                     (r = sshpkt_get_string(ssh, NULL, NULL)) != 0) {
1951                                         free(msg);
1952                                         return r;
1953                                 }
1954                                 debug("Remote: %.900s", msg);
1955                                 free(msg);
1956                                 break;
1957                         case SSH2_MSG_DISCONNECT:
1958                                 if ((r = sshpkt_get_u32(ssh, &reason)) != 0 ||
1959                                     (r = sshpkt_get_string(ssh, &msg, NULL)) != 0)
1960                                         return r;
1961                                 /* Ignore normal client exit notifications */
1962                                 do_log2(ssh->state->server_side &&
1963                                     reason == SSH2_DISCONNECT_BY_APPLICATION ?
1964                                     SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_ERROR,
1965                                     "Received disconnect from %s port %d:"
1966                                     "%u: %.400s", ssh_remote_ipaddr(ssh),
1967                                     ssh_remote_port(ssh), reason, msg);
1968                                 free(msg);
1969                                 return SSH_ERR_DISCONNECTED;
1970                         case SSH2_MSG_UNIMPLEMENTED:
1971                                 if ((r = sshpkt_get_u32(ssh, &seqnr)) != 0)
1972                                         return r;
1973                                 debug("Received SSH2_MSG_UNIMPLEMENTED for %u",
1974                                     seqnr);
1975                                 break;
1976                         default:
1977                                 return 0;
1978                         }
1979                 } else {
1980                         r = ssh_packet_read_poll1(ssh, typep);
1981                         switch (*typep) {
1982                         case SSH_MSG_NONE:
1983                                 return SSH_MSG_NONE;
1984                         case SSH_MSG_IGNORE:
1985                                 break;
1986                         case SSH_MSG_DEBUG:
1987                                 if ((r = sshpkt_get_string(ssh, &msg, NULL)) != 0)
1988                                         return r;
1989                                 debug("Remote: %.900s", msg);
1990                                 free(msg);
1991                                 break;
1992                         case SSH_MSG_DISCONNECT:
1993                                 if ((r = sshpkt_get_string(ssh, &msg, NULL)) != 0)
1994                                         return r;
1995                                 logit("Received disconnect from %s port %d: "
1996                                     "%.400s", ssh_remote_ipaddr(ssh),
1997                                     ssh_remote_port(ssh), msg);
1998                                 free(msg);
1999                                 return SSH_ERR_DISCONNECTED;
2000                         default:
2001                                 DBG(debug("received packet type %d", *typep));
2002                                 return 0;
2003                         }
2004                 }
2005         }
2006 }
2007
2008 /*
2009  * Buffers the given amount of input characters.  This is intended to be used
2010  * together with packet_read_poll.
2011  */
2012
2013 int
2014 ssh_packet_process_incoming(struct ssh *ssh, const char *buf, u_int len)
2015 {
2016         struct session_state *state = ssh->state;
2017         int r;
2018
2019         if (state->packet_discard) {
2020                 state->keep_alive_timeouts = 0; /* ?? */
2021                 if (len >= state->packet_discard) {
2022                         if ((r = ssh_packet_stop_discard(ssh)) != 0)
2023                                 return r;
2024                 }
2025                 state->packet_discard -= len;
2026                 return 0;
2027         }
2028         if ((r = sshbuf_put(ssh->state->input, buf, len)) != 0)
2029                 return r;
2030
2031         return 0;
2032 }
2033
2034 int
2035 ssh_packet_remaining(struct ssh *ssh)
2036 {
2037         return sshbuf_len(ssh->state->incoming_packet);
2038 }
2039
2040 /*
2041  * Sends a diagnostic message from the server to the client.  This message
2042  * can be sent at any time (but not while constructing another message). The
2043  * message is printed immediately, but only if the client is being executed
2044  * in verbose mode.  These messages are primarily intended to ease debugging
2045  * authentication problems.   The length of the formatted message must not
2046  * exceed 1024 bytes.  This will automatically call ssh_packet_write_wait.
2047  */
2048 void
2049 ssh_packet_send_debug(struct ssh *ssh, const char *fmt,...)
2050 {
2051         char buf[1024];
2052         va_list args;
2053         int r;
2054
2055         if (compat20 && (ssh->compat & SSH_BUG_DEBUG))
2056                 return;
2057
2058         va_start(args, fmt);
2059         vsnprintf(buf, sizeof(buf), fmt, args);
2060         va_end(args);
2061
2062         if (compat20) {
2063                 if ((r = sshpkt_start(ssh, SSH2_MSG_DEBUG)) != 0 ||
2064                     (r = sshpkt_put_u8(ssh, 0)) != 0 || /* always display */
2065                     (r = sshpkt_put_cstring(ssh, buf)) != 0 ||
2066                     (r = sshpkt_put_cstring(ssh, "")) != 0 ||
2067                     (r = sshpkt_send(ssh)) != 0)
2068                         fatal("%s: %s", __func__, ssh_err(r));
2069         } else {
2070                 if ((r = sshpkt_start(ssh, SSH_MSG_DEBUG)) != 0 ||
2071                     (r = sshpkt_put_cstring(ssh, buf)) != 0 ||
2072                     (r = sshpkt_send(ssh)) != 0)
2073                         fatal("%s: %s", __func__, ssh_err(r));
2074         }
2075         if ((r = ssh_packet_write_wait(ssh)) != 0)
2076                 fatal("%s: %s", __func__, ssh_err(r));
2077 }
2078
2079 /*
2080  * Pretty-print connection-terminating errors and exit.
2081  */
2082 void
2083 sshpkt_fatal(struct ssh *ssh, const char *tag, int r)
2084 {
2085         switch (r) {
2086         case SSH_ERR_CONN_CLOSED:
2087                 logdie("Connection closed by %.200s port %d",
2088                     ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
2089         case SSH_ERR_CONN_TIMEOUT:
2090                 logdie("Connection %s %.200s port %d timed out",
2091                     ssh->state->server_side ? "from" : "to",
2092                     ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
2093         case SSH_ERR_DISCONNECTED:
2094                 logdie("Disconnected from %.200s port %d",
2095                     ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
2096         case SSH_ERR_SYSTEM_ERROR:
2097                 if (errno == ECONNRESET)
2098                         logdie("Connection reset by %.200s port %d",
2099                             ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
2100                 /* FALLTHROUGH */
2101         case SSH_ERR_NO_CIPHER_ALG_MATCH:
2102         case SSH_ERR_NO_MAC_ALG_MATCH:
2103         case SSH_ERR_NO_COMPRESS_ALG_MATCH:
2104         case SSH_ERR_NO_KEX_ALG_MATCH:
2105         case SSH_ERR_NO_HOSTKEY_ALG_MATCH:
2106                 if (ssh && ssh->kex && ssh->kex->failed_choice) {
2107                         BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL, "ssh");
2108                         logdie("Unable to negotiate with %.200s port %d: %s. "
2109                             "Their offer: %s", ssh_remote_ipaddr(ssh),
2110                             ssh_remote_port(ssh), ssh_err(r),
2111                             ssh->kex->failed_choice);
2112                 }
2113                 /* FALLTHROUGH */
2114         default:
2115                 logdie("%s%sConnection %s %.200s port %d: %s",
2116                     tag != NULL ? tag : "", tag != NULL ? ": " : "",
2117                     ssh->state->server_side ? "from" : "to",
2118                     ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), ssh_err(r));
2119         }
2120 }
2121
2122 /*
2123  * Logs the error plus constructs and sends a disconnect packet, closes the
2124  * connection, and exits.  This function never returns. The error message
2125  * should not contain a newline.  The length of the formatted message must
2126  * not exceed 1024 bytes.
2127  */
2128 void
2129 ssh_packet_disconnect(struct ssh *ssh, const char *fmt,...)
2130 {
2131         char buf[1024];
2132         va_list args;
2133         static int disconnecting = 0;
2134         int r;
2135
2136         if (disconnecting)      /* Guard against recursive invocations. */
2137                 fatal("packet_disconnect called recursively.");
2138         disconnecting = 1;
2139
2140         /*
2141          * Format the message.  Note that the caller must make sure the
2142          * message is of limited size.
2143          */
2144         va_start(args, fmt);
2145         vsnprintf(buf, sizeof(buf), fmt, args);
2146         va_end(args);
2147
2148         /* Display the error locally */
2149         logit("Disconnecting: %.100s", buf);
2150
2151         /*
2152          * Send the disconnect message to the other side, and wait
2153          * for it to get sent.
2154          */
2155         if ((r = sshpkt_disconnect(ssh, "%s", buf)) != 0)
2156                 sshpkt_fatal(ssh, __func__, r);
2157
2158         if ((r = ssh_packet_write_wait(ssh)) != 0)
2159                 sshpkt_fatal(ssh, __func__, r);
2160
2161         /* Close the connection. */
2162         ssh_packet_close(ssh);
2163         cleanup_exit(255);
2164 }
2165
2166 /*
2167  * Checks if there is any buffered output, and tries to write some of
2168  * the output.
2169  */
2170 int
2171 ssh_packet_write_poll(struct ssh *ssh)
2172 {
2173         struct session_state *state = ssh->state;
2174         int len = sshbuf_len(state->output);
2175         int r;
2176
2177         if (len > 0) {
2178                 len = write(state->connection_out,
2179                     sshbuf_ptr(state->output), len);
2180                 if (len == -1) {
2181                         if (errno == EINTR || errno == EAGAIN ||
2182                             errno == EWOULDBLOCK)
2183                                 return 0;
2184                         return SSH_ERR_SYSTEM_ERROR;
2185                 }
2186                 if (len == 0)
2187                         return SSH_ERR_CONN_CLOSED;
2188                 if ((r = sshbuf_consume(state->output, len)) != 0)
2189                         return r;
2190         }
2191         return 0;
2192 }
2193
2194 /*
2195  * Calls packet_write_poll repeatedly until all pending output data has been
2196  * written.
2197  */
2198 int
2199 ssh_packet_write_wait(struct ssh *ssh)
2200 {
2201         fd_set *setp;
2202         int ret, r, ms_remain = 0;
2203         struct timeval start, timeout, *timeoutp = NULL;
2204         struct session_state *state = ssh->state;
2205
2206         setp = calloc(howmany(state->connection_out + 1,
2207             NFDBITS), sizeof(fd_mask));
2208         if (setp == NULL)
2209                 return SSH_ERR_ALLOC_FAIL;
2210         if ((r = ssh_packet_write_poll(ssh)) != 0) {
2211                 free(setp);
2212                 return r;
2213         }
2214         while (ssh_packet_have_data_to_write(ssh)) {
2215                 memset(setp, 0, howmany(state->connection_out + 1,
2216                     NFDBITS) * sizeof(fd_mask));
2217                 FD_SET(state->connection_out, setp);
2218
2219                 if (state->packet_timeout_ms > 0) {
2220                         ms_remain = state->packet_timeout_ms;
2221                         timeoutp = &timeout;
2222                 }
2223                 for (;;) {
2224                         if (state->packet_timeout_ms != -1) {
2225                                 ms_to_timeval(&timeout, ms_remain);
2226                                 gettimeofday(&start, NULL);
2227                         }
2228                         if ((ret = select(state->connection_out + 1,
2229                             NULL, setp, NULL, timeoutp)) >= 0)
2230                                 break;
2231                         if (errno != EAGAIN && errno != EINTR &&
2232                             errno != EWOULDBLOCK)
2233                                 break;
2234                         if (state->packet_timeout_ms == -1)
2235                                 continue;
2236                         ms_subtract_diff(&start, &ms_remain);
2237                         if (ms_remain <= 0) {
2238                                 ret = 0;
2239                                 break;
2240                         }
2241                 }
2242                 if (ret == 0) {
2243                         free(setp);
2244                         return SSH_ERR_CONN_TIMEOUT;
2245                 }
2246                 if ((r = ssh_packet_write_poll(ssh)) != 0) {
2247                         free(setp);
2248                         return r;
2249                 }
2250         }
2251         free(setp);
2252         return 0;
2253 }
2254
2255 /* Returns true if there is buffered data to write to the connection. */
2256
2257 int
2258 ssh_packet_have_data_to_write(struct ssh *ssh)
2259 {
2260         return sshbuf_len(ssh->state->output) != 0;
2261 }
2262
2263 /* Returns true if there is not too much data to write to the connection. */
2264
2265 int
2266 ssh_packet_not_very_much_data_to_write(struct ssh *ssh)
2267 {
2268         if (ssh->state->interactive_mode)
2269                 return sshbuf_len(ssh->state->output) < 16384;
2270         else
2271                 return sshbuf_len(ssh->state->output) < 128 * 1024;
2272 }
2273
2274 void
2275 ssh_packet_set_tos(struct ssh *ssh, int tos)
2276 {
2277 #ifndef IP_TOS_IS_BROKEN
2278         if (!ssh_packet_connection_is_on_socket(ssh))
2279                 return;
2280         switch (ssh_packet_connection_af(ssh)) {
2281 # ifdef IP_TOS
2282         case AF_INET:
2283                 debug3("%s: set IP_TOS 0x%02x", __func__, tos);
2284                 if (setsockopt(ssh->state->connection_in,
2285                     IPPROTO_IP, IP_TOS, &tos, sizeof(tos)) < 0)
2286                         error("setsockopt IP_TOS %d: %.100s:",
2287                             tos, strerror(errno));
2288                 break;
2289 # endif /* IP_TOS */
2290 # ifdef IPV6_TCLASS
2291         case AF_INET6:
2292                 debug3("%s: set IPV6_TCLASS 0x%02x", __func__, tos);
2293                 if (setsockopt(ssh->state->connection_in,
2294                     IPPROTO_IPV6, IPV6_TCLASS, &tos, sizeof(tos)) < 0)
2295                         error("setsockopt IPV6_TCLASS %d: %.100s:",
2296                             tos, strerror(errno));
2297                 break;
2298 # endif /* IPV6_TCLASS */
2299         }
2300 #endif /* IP_TOS_IS_BROKEN */
2301 }
2302
2303 /* Informs that the current session is interactive.  Sets IP flags for that. */
2304
2305 void
2306 ssh_packet_set_interactive(struct ssh *ssh, int interactive, int qos_interactive, int qos_bulk)
2307 {
2308         struct session_state *state = ssh->state;
2309
2310         if (state->set_interactive_called)
2311                 return;
2312         state->set_interactive_called = 1;
2313
2314         /* Record that we are in interactive mode. */
2315         state->interactive_mode = interactive;
2316
2317         /* Only set socket options if using a socket.  */
2318         if (!ssh_packet_connection_is_on_socket(ssh))
2319                 return;
2320         set_nodelay(state->connection_in);
2321         ssh_packet_set_tos(ssh, interactive ? qos_interactive :
2322             qos_bulk);
2323 }
2324
2325 /* Returns true if the current connection is interactive. */
2326
2327 int
2328 ssh_packet_is_interactive(struct ssh *ssh)
2329 {
2330         return ssh->state->interactive_mode;
2331 }
2332
2333 int
2334 ssh_packet_set_maxsize(struct ssh *ssh, u_int s)
2335 {
2336         struct session_state *state = ssh->state;
2337
2338         if (state->set_maxsize_called) {
2339                 logit("packet_set_maxsize: called twice: old %d new %d",
2340                     state->max_packet_size, s);
2341                 return -1;
2342         }
2343         if (s < 4 * 1024 || s > 1024 * 1024) {
2344                 logit("packet_set_maxsize: bad size %d", s);
2345                 return -1;
2346         }
2347         state->set_maxsize_called = 1;
2348         debug("packet_set_maxsize: setting to %d", s);
2349         state->max_packet_size = s;
2350         return s;
2351 }
2352
2353 int
2354 ssh_packet_inc_alive_timeouts(struct ssh *ssh)
2355 {
2356         return ++ssh->state->keep_alive_timeouts;
2357 }
2358
2359 void
2360 ssh_packet_set_alive_timeouts(struct ssh *ssh, int ka)
2361 {
2362         ssh->state->keep_alive_timeouts = ka;
2363 }
2364
2365 u_int
2366 ssh_packet_get_maxsize(struct ssh *ssh)
2367 {
2368         return ssh->state->max_packet_size;
2369 }
2370
2371 /*
2372  * 9.2.  Ignored Data Message
2373  *
2374  *   byte      SSH_MSG_IGNORE
2375  *   string    data
2376  *
2377  * All implementations MUST understand (and ignore) this message at any
2378  * time (after receiving the protocol version). No implementation is
2379  * required to send them. This message can be used as an additional
2380  * protection measure against advanced traffic analysis techniques.
2381  */
2382 void
2383 ssh_packet_send_ignore(struct ssh *ssh, int nbytes)
2384 {
2385         u_int32_t rnd = 0;
2386         int r, i;
2387
2388         if ((r = sshpkt_start(ssh, compat20 ?
2389             SSH2_MSG_IGNORE : SSH_MSG_IGNORE)) != 0 ||
2390             (r = sshpkt_put_u32(ssh, nbytes)) != 0)
2391                 fatal("%s: %s", __func__, ssh_err(r));
2392         for (i = 0; i < nbytes; i++) {
2393                 if (i % 4 == 0)
2394                         rnd = arc4random();
2395                 if ((r = sshpkt_put_u8(ssh, (u_char)rnd & 0xff)) != 0)
2396                         fatal("%s: %s", __func__, ssh_err(r));
2397                 rnd >>= 8;
2398         }
2399 }
2400
2401 void
2402 ssh_packet_set_rekey_limits(struct ssh *ssh, u_int64_t bytes, time_t seconds)
2403 {
2404         debug3("rekey after %llu bytes, %d seconds", (unsigned long long)bytes,
2405             (int)seconds);
2406         ssh->state->rekey_limit = bytes;
2407         ssh->state->rekey_interval = seconds;
2408 }
2409
2410 time_t
2411 ssh_packet_get_rekey_timeout(struct ssh *ssh)
2412 {
2413         time_t seconds;
2414
2415         seconds = ssh->state->rekey_time + ssh->state->rekey_interval -
2416             monotime();
2417         return (seconds <= 0 ? 1 : seconds);
2418 }
2419
2420 void
2421 ssh_packet_set_server(struct ssh *ssh)
2422 {
2423         ssh->state->server_side = 1;
2424 }
2425
2426 void
2427 ssh_packet_set_authenticated(struct ssh *ssh)
2428 {
2429         ssh->state->after_authentication = 1;
2430 }
2431
2432 void *
2433 ssh_packet_get_input(struct ssh *ssh)
2434 {
2435         return (void *)ssh->state->input;
2436 }
2437
2438 void *
2439 ssh_packet_get_output(struct ssh *ssh)
2440 {
2441         return (void *)ssh->state->output;
2442 }
2443
2444 /* Reset after_authentication and reset compression in post-auth privsep */
2445 static int
2446 ssh_packet_set_postauth(struct ssh *ssh)
2447 {
2448         int r;
2449
2450         debug("%s: called", __func__);
2451         /* This was set in net child, but is not visible in user child */
2452         ssh->state->after_authentication = 1;
2453         ssh->state->rekeying = 0;
2454         if ((r = ssh_packet_enable_delayed_compress(ssh)) != 0)
2455                 return r;
2456         return 0;
2457 }
2458
2459 /* Packet state (de-)serialization for privsep */
2460
2461 /* turn kex into a blob for packet state serialization */
2462 static int
2463 kex_to_blob(struct sshbuf *m, struct kex *kex)
2464 {
2465         int r;
2466
2467         if ((r = sshbuf_put_string(m, kex->session_id,
2468             kex->session_id_len)) != 0 ||
2469             (r = sshbuf_put_u32(m, kex->we_need)) != 0 ||
2470             (r = sshbuf_put_u32(m, kex->hostkey_type)) != 0 ||
2471             (r = sshbuf_put_u32(m, kex->kex_type)) != 0 ||
2472             (r = sshbuf_put_stringb(m, kex->my)) != 0 ||
2473             (r = sshbuf_put_stringb(m, kex->peer)) != 0 ||
2474             (r = sshbuf_put_u32(m, kex->flags)) != 0 ||
2475             (r = sshbuf_put_cstring(m, kex->client_version_string)) != 0 ||
2476             (r = sshbuf_put_cstring(m, kex->server_version_string)) != 0)
2477                 return r;
2478         return 0;
2479 }
2480
2481 /* turn key exchange results into a blob for packet state serialization */
2482 static int
2483 newkeys_to_blob(struct sshbuf *m, struct ssh *ssh, int mode)
2484 {
2485         struct sshbuf *b;
2486         struct sshcipher_ctx *cc;
2487         struct sshcomp *comp;
2488         struct sshenc *enc;
2489         struct sshmac *mac;
2490         struct newkeys *newkey;
2491         int r;
2492
2493         if ((newkey = ssh->state->newkeys[mode]) == NULL)
2494                 return SSH_ERR_INTERNAL_ERROR;
2495         enc = &newkey->enc;
2496         mac = &newkey->mac;
2497         comp = &newkey->comp;
2498         cc = (mode == MODE_OUT) ? ssh->state->send_context :
2499             ssh->state->receive_context;
2500         if ((r = cipher_get_keyiv(cc, enc->iv, enc->iv_len)) != 0)
2501                 return r;
2502         if ((b = sshbuf_new()) == NULL)
2503                 return SSH_ERR_ALLOC_FAIL;
2504         /* The cipher struct is constant and shared, you export pointer */
2505         if ((r = sshbuf_put_cstring(b, enc->name)) != 0 ||
2506             (r = sshbuf_put(b, &enc->cipher, sizeof(enc->cipher))) != 0 ||
2507             (r = sshbuf_put_u32(b, enc->enabled)) != 0 ||
2508             (r = sshbuf_put_u32(b, enc->block_size)) != 0 ||
2509             (r = sshbuf_put_string(b, enc->key, enc->key_len)) != 0 ||
2510             (r = sshbuf_put_string(b, enc->iv, enc->iv_len)) != 0)
2511                 goto out;
2512         if (cipher_authlen(enc->cipher) == 0) {
2513                 if ((r = sshbuf_put_cstring(b, mac->name)) != 0 ||
2514                     (r = sshbuf_put_u32(b, mac->enabled)) != 0 ||
2515                     (r = sshbuf_put_string(b, mac->key, mac->key_len)) != 0)
2516                         goto out;
2517         }
2518         if ((r = sshbuf_put_u32(b, comp->type)) != 0 ||
2519             (r = sshbuf_put_cstring(b, comp->name)) != 0)
2520                 goto out;
2521         r = sshbuf_put_stringb(m, b);
2522  out:
2523         sshbuf_free(b);
2524         return r;
2525 }
2526
2527 /* serialize packet state into a blob */
2528 int
2529 ssh_packet_get_state(struct ssh *ssh, struct sshbuf *m)
2530 {
2531         struct session_state *state = ssh->state;
2532         u_char *p;
2533         size_t slen, rlen;
2534         int r, ssh1cipher;
2535
2536         if (!compat20) {
2537                 ssh1cipher = cipher_ctx_get_number(state->receive_context);
2538                 slen = cipher_get_keyiv_len(state->send_context);
2539                 rlen = cipher_get_keyiv_len(state->receive_context);
2540                 if ((r = sshbuf_put_u32(m, state->remote_protocol_flags)) != 0 ||
2541                     (r = sshbuf_put_u32(m, ssh1cipher)) != 0 ||
2542                     (r = sshbuf_put_string(m, state->ssh1_key, state->ssh1_keylen)) != 0 ||
2543                     (r = sshbuf_put_u32(m, slen)) != 0 ||
2544                     (r = sshbuf_reserve(m, slen, &p)) != 0 ||
2545                     (r = cipher_get_keyiv(state->send_context, p, slen)) != 0 ||
2546                     (r = sshbuf_put_u32(m, rlen)) != 0 ||
2547                     (r = sshbuf_reserve(m, rlen, &p)) != 0 ||
2548                     (r = cipher_get_keyiv(state->receive_context, p, rlen)) != 0)
2549                         return r;
2550         } else {
2551                 if ((r = kex_to_blob(m, ssh->kex)) != 0 ||
2552                     (r = newkeys_to_blob(m, ssh, MODE_OUT)) != 0 ||
2553                     (r = newkeys_to_blob(m, ssh, MODE_IN)) != 0 ||
2554                     (r = sshbuf_put_u64(m, state->rekey_limit)) != 0 ||
2555                     (r = sshbuf_put_u32(m, state->rekey_interval)) != 0 ||
2556                     (r = sshbuf_put_u32(m, state->p_send.seqnr)) != 0 ||
2557                     (r = sshbuf_put_u64(m, state->p_send.blocks)) != 0 ||
2558                     (r = sshbuf_put_u32(m, state->p_send.packets)) != 0 ||
2559                     (r = sshbuf_put_u64(m, state->p_send.bytes)) != 0 ||
2560                     (r = sshbuf_put_u32(m, state->p_read.seqnr)) != 0 ||
2561                     (r = sshbuf_put_u64(m, state->p_read.blocks)) != 0 ||
2562                     (r = sshbuf_put_u32(m, state->p_read.packets)) != 0 ||
2563                     (r = sshbuf_put_u64(m, state->p_read.bytes)) != 0)
2564                         return r;
2565         }
2566
2567         slen = cipher_get_keycontext(state->send_context, NULL);
2568         rlen = cipher_get_keycontext(state->receive_context, NULL);
2569         if ((r = sshbuf_put_u32(m, slen)) != 0 ||
2570             (r = sshbuf_reserve(m, slen, &p)) != 0)
2571                 return r;
2572         if (cipher_get_keycontext(state->send_context, p) != (int)slen)
2573                 return SSH_ERR_INTERNAL_ERROR;
2574         if ((r = sshbuf_put_u32(m, rlen)) != 0 ||
2575             (r = sshbuf_reserve(m, rlen, &p)) != 0)
2576                 return r;
2577         if (cipher_get_keycontext(state->receive_context, p) != (int)rlen)
2578                 return SSH_ERR_INTERNAL_ERROR;
2579         if ((r = sshbuf_put_stringb(m, state->input)) != 0 ||
2580             (r = sshbuf_put_stringb(m, state->output)) != 0)
2581                 return r;
2582
2583         return 0;
2584 }
2585
2586 /* restore key exchange results from blob for packet state de-serialization */
2587 static int
2588 newkeys_from_blob(struct sshbuf *m, struct ssh *ssh, int mode)
2589 {
2590         struct sshbuf *b = NULL;
2591         struct sshcomp *comp;
2592         struct sshenc *enc;
2593         struct sshmac *mac;
2594         struct newkeys *newkey = NULL;
2595         size_t keylen, ivlen, maclen;
2596         int r;
2597
2598         if ((newkey = calloc(1, sizeof(*newkey))) == NULL) {
2599                 r = SSH_ERR_ALLOC_FAIL;
2600                 goto out;
2601         }
2602         if ((r = sshbuf_froms(m, &b)) != 0)
2603                 goto out;
2604 #ifdef DEBUG_PK
2605         sshbuf_dump(b, stderr);
2606 #endif
2607         enc = &newkey->enc;
2608         mac = &newkey->mac;
2609         comp = &newkey->comp;
2610
2611         if ((r = sshbuf_get_cstring(b, &enc->name, NULL)) != 0 ||
2612             (r = sshbuf_get(b, &enc->cipher, sizeof(enc->cipher))) != 0 ||
2613             (r = sshbuf_get_u32(b, (u_int *)&enc->enabled)) != 0 ||
2614             (r = sshbuf_get_u32(b, &enc->block_size)) != 0 ||
2615             (r = sshbuf_get_string(b, &enc->key, &keylen)) != 0 ||
2616             (r = sshbuf_get_string(b, &enc->iv, &ivlen)) != 0)
2617                 goto out;
2618         if (cipher_authlen(enc->cipher) == 0) {
2619                 if ((r = sshbuf_get_cstring(b, &mac->name, NULL)) != 0)
2620                         goto out;
2621                 if ((r = mac_setup(mac, mac->name)) != 0)
2622                         goto out;
2623                 if ((r = sshbuf_get_u32(b, (u_int *)&mac->enabled)) != 0 ||
2624                     (r = sshbuf_get_string(b, &mac->key, &maclen)) != 0)
2625                         goto out;
2626                 if (maclen > mac->key_len) {
2627                         r = SSH_ERR_INVALID_FORMAT;
2628                         goto out;
2629                 }
2630                 mac->key_len = maclen;
2631         }
2632         if ((r = sshbuf_get_u32(b, &comp->type)) != 0 ||
2633             (r = sshbuf_get_cstring(b, &comp->name, NULL)) != 0)
2634                 goto out;
2635         if (enc->name == NULL ||
2636             cipher_by_name(enc->name) != enc->cipher) {
2637                 r = SSH_ERR_INVALID_FORMAT;
2638                 goto out;
2639         }
2640         if (sshbuf_len(b) != 0) {
2641                 r = SSH_ERR_INVALID_FORMAT;
2642                 goto out;
2643         }
2644         enc->key_len = keylen;
2645         enc->iv_len = ivlen;
2646         ssh->kex->newkeys[mode] = newkey;
2647         newkey = NULL;
2648         r = 0;
2649  out:
2650         free(newkey);
2651         sshbuf_free(b);
2652         return r;
2653 }
2654
2655 /* restore kex from blob for packet state de-serialization */
2656 static int
2657 kex_from_blob(struct sshbuf *m, struct kex **kexp)
2658 {
2659         struct kex *kex;
2660         int r;
2661
2662         if ((kex = calloc(1, sizeof(struct kex))) == NULL ||
2663             (kex->my = sshbuf_new()) == NULL ||
2664             (kex->peer = sshbuf_new()) == NULL) {
2665                 r = SSH_ERR_ALLOC_FAIL;
2666                 goto out;
2667         }
2668         if ((r = sshbuf_get_string(m, &kex->session_id, &kex->session_id_len)) != 0 ||
2669             (r = sshbuf_get_u32(m, &kex->we_need)) != 0 ||
2670             (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_type)) != 0 ||
2671             (r = sshbuf_get_u32(m, &kex->kex_type)) != 0 ||
2672             (r = sshbuf_get_stringb(m, kex->my)) != 0 ||
2673             (r = sshbuf_get_stringb(m, kex->peer)) != 0 ||
2674             (r = sshbuf_get_u32(m, &kex->flags)) != 0 ||
2675             (r = sshbuf_get_cstring(m, &kex->client_version_string, NULL)) != 0 ||
2676             (r = sshbuf_get_cstring(m, &kex->server_version_string, NULL)) != 0)
2677                 goto out;
2678         kex->server = 1;
2679         kex->done = 1;
2680         r = 0;
2681  out:
2682         if (r != 0 || kexp == NULL) {
2683                 if (kex != NULL) {
2684                         sshbuf_free(kex->my);
2685                         sshbuf_free(kex->peer);
2686                         free(kex);
2687                 }
2688                 if (kexp != NULL)
2689                         *kexp = NULL;
2690         } else {
2691                 *kexp = kex;
2692         }
2693         return r;
2694 }
2695
2696 /*
2697  * Restore packet state from content of blob 'm' (de-serialization).
2698  * Note that 'm' will be partially consumed on parsing or any other errors.
2699  */
2700 int
2701 ssh_packet_set_state(struct ssh *ssh, struct sshbuf *m)
2702 {
2703         struct session_state *state = ssh->state;
2704         const u_char *ssh1key, *ivin, *ivout, *keyin, *keyout, *input, *output;
2705         size_t ssh1keylen, rlen, slen, ilen, olen;
2706         int r;
2707         u_int ssh1cipher = 0;
2708
2709         if (!compat20) {
2710                 if ((r = sshbuf_get_u32(m, &state->remote_protocol_flags)) != 0 ||
2711                     (r = sshbuf_get_u32(m, &ssh1cipher)) != 0 ||
2712                     (r = sshbuf_get_string_direct(m, &ssh1key, &ssh1keylen)) != 0 ||
2713                     (r = sshbuf_get_string_direct(m, &ivout, &slen)) != 0 ||
2714                     (r = sshbuf_get_string_direct(m, &ivin, &rlen)) != 0)
2715                         return r;
2716                 if (ssh1cipher > INT_MAX)
2717                         return SSH_ERR_KEY_UNKNOWN_CIPHER;
2718                 ssh_packet_set_encryption_key(ssh, ssh1key, ssh1keylen,
2719                     (int)ssh1cipher);
2720                 if (cipher_get_keyiv_len(state->send_context) != (int)slen ||
2721                     cipher_get_keyiv_len(state->receive_context) != (int)rlen)
2722                         return SSH_ERR_INVALID_FORMAT;
2723                 if ((r = cipher_set_keyiv(state->send_context, ivout)) != 0 ||
2724                     (r = cipher_set_keyiv(state->receive_context, ivin)) != 0)
2725                         return r;
2726         } else {
2727                 if ((r = kex_from_blob(m, &ssh->kex)) != 0 ||
2728                     (r = newkeys_from_blob(m, ssh, MODE_OUT)) != 0 ||
2729                     (r = newkeys_from_blob(m, ssh, MODE_IN)) != 0 ||
2730                     (r = sshbuf_get_u64(m, &state->rekey_limit)) != 0 ||
2731                     (r = sshbuf_get_u32(m, &state->rekey_interval)) != 0 ||
2732                     (r = sshbuf_get_u32(m, &state->p_send.seqnr)) != 0 ||
2733                     (r = sshbuf_get_u64(m, &state->p_send.blocks)) != 0 ||
2734                     (r = sshbuf_get_u32(m, &state->p_send.packets)) != 0 ||
2735                     (r = sshbuf_get_u64(m, &state->p_send.bytes)) != 0 ||
2736                     (r = sshbuf_get_u32(m, &state->p_read.seqnr)) != 0 ||
2737                     (r = sshbuf_get_u64(m, &state->p_read.blocks)) != 0 ||
2738                     (r = sshbuf_get_u32(m, &state->p_read.packets)) != 0 ||
2739                     (r = sshbuf_get_u64(m, &state->p_read.bytes)) != 0)
2740                         return r;
2741                 /*
2742                  * We set the time here so that in post-auth privsep slave we
2743                  * count from the completion of the authentication.
2744                  */
2745                 state->rekey_time = monotime();
2746                 /* XXX ssh_set_newkeys overrides p_read.packets? XXX */
2747                 if ((r = ssh_set_newkeys(ssh, MODE_IN)) != 0 ||
2748                     (r = ssh_set_newkeys(ssh, MODE_OUT)) != 0)
2749                         return r;
2750         }
2751         if ((r = sshbuf_get_string_direct(m, &keyout, &slen)) != 0 ||
2752             (r = sshbuf_get_string_direct(m, &keyin, &rlen)) != 0)
2753                 return r;
2754         if (cipher_get_keycontext(state->send_context, NULL) != (int)slen ||
2755             cipher_get_keycontext(state->receive_context, NULL) != (int)rlen)
2756                 return SSH_ERR_INVALID_FORMAT;
2757         cipher_set_keycontext(state->send_context, keyout);
2758         cipher_set_keycontext(state->receive_context, keyin);
2759
2760         if ((r = ssh_packet_set_postauth(ssh)) != 0)
2761                 return r;
2762
2763         sshbuf_reset(state->input);
2764         sshbuf_reset(state->output);
2765         if ((r = sshbuf_get_string_direct(m, &input, &ilen)) != 0 ||
2766             (r = sshbuf_get_string_direct(m, &output, &olen)) != 0 ||
2767             (r = sshbuf_put(state->input, input, ilen)) != 0 ||
2768             (r = sshbuf_put(state->output, output, olen)) != 0)
2769                 return r;
2770
2771         if (sshbuf_len(m))
2772                 return SSH_ERR_INVALID_FORMAT;
2773         debug3("%s: done", __func__);
2774         return 0;
2775 }
2776
2777 /* NEW API */
2778
2779 /* put data to the outgoing packet */
2780
2781 int
2782 sshpkt_put(struct ssh *ssh, const void *v, size_t len)
2783 {
2784         return sshbuf_put(ssh->state->outgoing_packet, v, len);
2785 }
2786
2787 int
2788 sshpkt_putb(struct ssh *ssh, const struct sshbuf *b)
2789 {
2790         return sshbuf_putb(ssh->state->outgoing_packet, b);
2791 }
2792
2793 int
2794 sshpkt_put_u8(struct ssh *ssh, u_char val)
2795 {
2796         return sshbuf_put_u8(ssh->state->outgoing_packet, val);
2797 }
2798
2799 int
2800 sshpkt_put_u32(struct ssh *ssh, u_int32_t val)
2801 {
2802         return sshbuf_put_u32(ssh->state->outgoing_packet, val);
2803 }
2804
2805 int
2806 sshpkt_put_u64(struct ssh *ssh, u_int64_t val)
2807 {
2808         return sshbuf_put_u64(ssh->state->outgoing_packet, val);
2809 }
2810
2811 int
2812 sshpkt_put_string(struct ssh *ssh, const void *v, size_t len)
2813 {
2814         return sshbuf_put_string(ssh->state->outgoing_packet, v, len);
2815 }
2816
2817 int
2818 sshpkt_put_cstring(struct ssh *ssh, const void *v)
2819 {
2820         return sshbuf_put_cstring(ssh->state->outgoing_packet, v);
2821 }
2822
2823 int
2824 sshpkt_put_stringb(struct ssh *ssh, const struct sshbuf *v)
2825 {
2826         return sshbuf_put_stringb(ssh->state->outgoing_packet, v);
2827 }
2828
2829 #ifdef WITH_OPENSSL
2830 #ifdef OPENSSL_HAS_ECC
2831 int
2832 sshpkt_put_ec(struct ssh *ssh, const EC_POINT *v, const EC_GROUP *g)
2833 {
2834         return sshbuf_put_ec(ssh->state->outgoing_packet, v, g);
2835 }
2836 #endif /* OPENSSL_HAS_ECC */
2837
2838 #ifdef WITH_SSH1
2839 int
2840 sshpkt_put_bignum1(struct ssh *ssh, const BIGNUM *v)
2841 {
2842         return sshbuf_put_bignum1(ssh->state->outgoing_packet, v);
2843 }
2844 #endif /* WITH_SSH1 */
2845
2846 int
2847 sshpkt_put_bignum2(struct ssh *ssh, const BIGNUM *v)
2848 {
2849         return sshbuf_put_bignum2(ssh->state->outgoing_packet, v);
2850 }
2851 #endif /* WITH_OPENSSL */
2852
2853 /* fetch data from the incoming packet */
2854
2855 int
2856 sshpkt_get(struct ssh *ssh, void *valp, size_t len)
2857 {
2858         return sshbuf_get(ssh->state->incoming_packet, valp, len);
2859 }
2860
2861 int
2862 sshpkt_get_u8(struct ssh *ssh, u_char *valp)
2863 {
2864         return sshbuf_get_u8(ssh->state->incoming_packet, valp);
2865 }
2866
2867 int
2868 sshpkt_get_u32(struct ssh *ssh, u_int32_t *valp)
2869 {
2870         return sshbuf_get_u32(ssh->state->incoming_packet, valp);
2871 }
2872
2873 int
2874 sshpkt_get_u64(struct ssh *ssh, u_int64_t *valp)
2875 {
2876         return sshbuf_get_u64(ssh->state->incoming_packet, valp);
2877 }
2878
2879 int
2880 sshpkt_get_string(struct ssh *ssh, u_char **valp, size_t *lenp)
2881 {
2882         return sshbuf_get_string(ssh->state->incoming_packet, valp, lenp);
2883 }
2884
2885 int
2886 sshpkt_get_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp)
2887 {
2888         return sshbuf_get_string_direct(ssh->state->incoming_packet, valp, lenp);
2889 }
2890
2891 int
2892 sshpkt_get_cstring(struct ssh *ssh, char **valp, size_t *lenp)
2893 {
2894         return sshbuf_get_cstring(ssh->state->incoming_packet, valp, lenp);
2895 }
2896
2897 #ifdef WITH_OPENSSL
2898 #ifdef OPENSSL_HAS_ECC
2899 int
2900 sshpkt_get_ec(struct ssh *ssh, EC_POINT *v, const EC_GROUP *g)
2901 {
2902         return sshbuf_get_ec(ssh->state->incoming_packet, v, g);
2903 }
2904 #endif /* OPENSSL_HAS_ECC */
2905
2906 #ifdef WITH_SSH1
2907 int
2908 sshpkt_get_bignum1(struct ssh *ssh, BIGNUM *v)
2909 {
2910         return sshbuf_get_bignum1(ssh->state->incoming_packet, v);
2911 }
2912 #endif /* WITH_SSH1 */
2913
2914 int
2915 sshpkt_get_bignum2(struct ssh *ssh, BIGNUM *v)
2916 {
2917         return sshbuf_get_bignum2(ssh->state->incoming_packet, v);
2918 }
2919 #endif /* WITH_OPENSSL */
2920
2921 int
2922 sshpkt_get_end(struct ssh *ssh)
2923 {
2924         if (sshbuf_len(ssh->state->incoming_packet) > 0)
2925                 return SSH_ERR_UNEXPECTED_TRAILING_DATA;
2926         return 0;
2927 }
2928
2929 const u_char *
2930 sshpkt_ptr(struct ssh *ssh, size_t *lenp)
2931 {
2932         if (lenp != NULL)
2933                 *lenp = sshbuf_len(ssh->state->incoming_packet);
2934         return sshbuf_ptr(ssh->state->incoming_packet);
2935 }
2936
2937 /* start a new packet */
2938
2939 int
2940 sshpkt_start(struct ssh *ssh, u_char type)
2941 {
2942         u_char buf[9];
2943         int len;
2944
2945         DBG(debug("packet_start[%d]", type));
2946         len = compat20 ? 6 : 9;
2947         memset(buf, 0, len - 1);
2948         buf[len - 1] = type;
2949         sshbuf_reset(ssh->state->outgoing_packet);
2950         return sshbuf_put(ssh->state->outgoing_packet, buf, len);
2951 }
2952
2953 static int
2954 ssh_packet_send_mux(struct ssh *ssh)
2955 {
2956         struct session_state *state = ssh->state;
2957         u_char type, *cp;
2958         size_t len;
2959         int r;
2960
2961         if (ssh->kex)
2962                 return SSH_ERR_INTERNAL_ERROR;
2963         len = sshbuf_len(state->outgoing_packet);
2964         if (len < 6)
2965                 return SSH_ERR_INTERNAL_ERROR;
2966         cp = sshbuf_mutable_ptr(state->outgoing_packet);
2967         type = cp[5];
2968         if (ssh_packet_log_type(type))
2969                 debug3("%s: type %u", __func__, type);
2970         /* drop everything, but the connection protocol */
2971         if (type >= SSH2_MSG_CONNECTION_MIN &&
2972             type <= SSH2_MSG_CONNECTION_MAX) {
2973                 POKE_U32(cp, len - 4);
2974                 if ((r = sshbuf_putb(state->output,
2975                     state->outgoing_packet)) != 0)
2976                         return r;
2977                 /* sshbuf_dump(state->output, stderr); */
2978         }
2979         sshbuf_reset(state->outgoing_packet);
2980         return 0;
2981 }
2982
2983 /* send it */
2984
2985 int
2986 sshpkt_send(struct ssh *ssh)
2987 {
2988         if (ssh->state && ssh->state->mux)
2989                 return ssh_packet_send_mux(ssh);
2990         if (compat20)
2991                 return ssh_packet_send2(ssh);
2992         else
2993                 return ssh_packet_send1(ssh);
2994 }
2995
2996 int
2997 sshpkt_disconnect(struct ssh *ssh, const char *fmt,...)
2998 {
2999         char buf[1024];
3000         va_list args;
3001         int r;
3002
3003         va_start(args, fmt);
3004         vsnprintf(buf, sizeof(buf), fmt, args);
3005         va_end(args);
3006
3007         if (compat20) {
3008                 if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 ||
3009                     (r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_PROTOCOL_ERROR)) != 0 ||
3010                     (r = sshpkt_put_cstring(ssh, buf)) != 0 ||
3011                     (r = sshpkt_put_cstring(ssh, "")) != 0 ||
3012                     (r = sshpkt_send(ssh)) != 0)
3013                         return r;
3014         } else {
3015                 if ((r = sshpkt_start(ssh, SSH_MSG_DISCONNECT)) != 0 ||
3016                     (r = sshpkt_put_cstring(ssh, buf)) != 0 ||
3017                     (r = sshpkt_send(ssh)) != 0)
3018                         return r;
3019         }
3020         return 0;
3021 }
3022
3023 /* roundup current message to pad bytes */
3024 int
3025 sshpkt_add_padding(struct ssh *ssh, u_char pad)
3026 {
3027         ssh->state->extra_pad = pad;
3028         return 0;
3029 }