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Diff for /src/usr.bin/ssh/packet.c between version 1.32 and 1.32.2.2

version 1.32, 2000/05/04 22:22:43 version 1.32.2.2, 2000/11/08 21:31:01
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 /*  /*
  *  
  * packet.c  
  *  
  * Author: Tatu Ylonen <ylo@cs.hut.fi>   * Author: Tatu Ylonen <ylo@cs.hut.fi>
  *  
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland   * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
  *                    All rights reserved   *                    All rights reserved
  *  
  * Created: Sat Mar 18 02:40:40 1995 ylo  
  *  
  * This file contains code implementing the packet protocol and communication   * This file contains code implementing the packet protocol and communication
  * with the other side.  This same code is used both on client and server side.   * with the other side.  This same code is used both on client and server side.
  *   *
    * As far as I am concerned, the code I have written for this software
    * can be used freely for any purpose.  Any derived versions of this
    * software must be clearly marked as such, and if the derived work is
    * incompatible with the protocol description in the RFC file, it must be
    * called by a name other than "ssh" or "Secure Shell".
    *
    *
  * SSH2 packet format added by Markus Friedl.   * SSH2 packet format added by Markus Friedl.
    * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  *   *
    * Redistribution and use in source and binary forms, with or without
    * modification, are permitted provided that the following conditions
    * are met:
    * 1. Redistributions of source code must retain the above copyright
    *    notice, this list of conditions and the following disclaimer.
    * 2. Redistributions in binary form must reproduce the above copyright
    *    notice, this list of conditions and the following disclaimer in the
    *    documentation and/or other materials provided with the distribution.
    *
    * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
    * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
    * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
    * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
    * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
    * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
    * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
    * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
    * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
    * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */   */
   
 #include "includes.h"  #include "includes.h"
 RCSID("$Id$");  RCSID("$OpenBSD$");
   
 #include "xmalloc.h"  #include "xmalloc.h"
 #include "buffer.h"  #include "buffer.h"
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 #include "bufaux.h"  #include "bufaux.h"
 #include "ssh.h"  #include "ssh.h"
 #include "crc32.h"  #include "crc32.h"
 #include "cipher.h"  
 #include "getput.h"  #include "getput.h"
   
 #include "compress.h"  #include "compress.h"
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 #include <openssl/dh.h>  #include <openssl/dh.h>
 #include <openssl/hmac.h>  #include <openssl/hmac.h>
 #include "buffer.h"  #include "buffer.h"
   #include "cipher.h"
 #include "kex.h"  #include "kex.h"
 #include "hmac.h"  #include "hmac.h"
   
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 void  void
 packet_set_connection(int fd_in, int fd_out)  packet_set_connection(int fd_in, int fd_out)
 {  {
           Cipher *none = cipher_by_name("none");
           if (none == NULL)
                   fatal("packet_set_connection: cannot load cipher 'none'");
         connection_in = fd_in;          connection_in = fd_in;
         connection_out = fd_out;          connection_out = fd_out;
         cipher_type = SSH_CIPHER_NONE;          cipher_type = SSH_CIPHER_NONE;
         cipher_set_key(&send_context, SSH_CIPHER_NONE, (unsigned char *) "", 0);          cipher_init(&send_context, none, (unsigned char *) "", 0, NULL, 0);
         cipher_set_key(&receive_context, SSH_CIPHER_NONE, (unsigned char *) "", 0);          cipher_init(&receive_context, none, (unsigned char *) "", 0, NULL, 0);
         if (!initialized) {          if (!initialized) {
                 initialized = 1;                  initialized = 1;
                 buffer_init(&input);                  buffer_init(&input);
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  */   */
   
 void  void
 packet_decrypt(CipherContext * cc, void *dest, void *src,  packet_decrypt(CipherContext *context, void *dest, void *src, unsigned int bytes)
     unsigned int bytes)  
 {  {
         int i;  
   
         if ((bytes % 8) != 0)  
                 fatal("packet_decrypt: bad ciphertext length %d", bytes);  
   
         /*          /*
          * Cryptographic attack detector for ssh - Modifications for packet.c           * Cryptographic attack detector for ssh - Modifications for packet.c
          * (C)1998 CORE-SDI, Buenos Aires Argentina Ariel Futoransky(futo@core-sdi.com)           * (C)1998 CORE-SDI, Buenos Aires Argentina Ariel Futoransky(futo@core-sdi.com)
          */           */
           if (!compat20 &&
         if (cc->type == SSH_CIPHER_NONE || compat20) {              context->cipher->number != SSH_CIPHER_NONE &&
                 i = DEATTACK_OK;              detect_attack(src, bytes, NULL) == DEATTACK_DETECTED)
         } else {  
                 i = detect_attack(src, bytes, NULL);  
         }  
         if (i == DEATTACK_DETECTED)  
                 packet_disconnect("crc32 compensation attack: network attack detected");                  packet_disconnect("crc32 compensation attack: network attack detected");
   
         cipher_decrypt(cc, dest, src, bytes);          cipher_decrypt(context, dest, src, bytes);
 }  }
   
 /*  /*
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 void  void
 packet_set_encryption_key(const unsigned char *key, unsigned int keylen,  packet_set_encryption_key(const unsigned char *key, unsigned int keylen,
     int cipher)      int number)
 {  {
           Cipher *cipher = cipher_by_number(number);
           if (cipher == NULL)
                   fatal("packet_set_encryption_key: unknown cipher number %d", number);
         if (keylen < 20)          if (keylen < 20)
                 fatal("keylen too small: %d", keylen);                  fatal("packet_set_encryption_key: keylen too small: %d", keylen);
           cipher_init(&receive_context, cipher, key, keylen, NULL, 0);
         /* All other ciphers use the same key in both directions for now. */          cipher_init(&send_context, cipher, key, keylen, NULL, 0);
         cipher_set_key(&receive_context, cipher, key, keylen);  
         cipher_set_key(&send_context, cipher, key, keylen);  
 }  }
   
 /* Starts constructing a packet to send. */  /* Starts constructing a packet to send. */
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         buffer_consume(&outgoing_packet, 8 - padding);          buffer_consume(&outgoing_packet, 8 - padding);
   
         /* Add check bytes. */          /* Add check bytes. */
         checksum = crc32((unsigned char *) buffer_ptr(&outgoing_packet),          checksum = ssh_crc32((unsigned char *) buffer_ptr(&outgoing_packet),
                          buffer_len(&outgoing_packet));              buffer_len(&outgoing_packet));
         PUT_32BIT(buf, checksum);          PUT_32BIT(buf, checksum);
         buffer_append(&outgoing_packet, buf, 4);          buffer_append(&outgoing_packet, buf, 4);
   
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                 mac  = &kex->mac[MODE_OUT];                  mac  = &kex->mac[MODE_OUT];
                 comp = &kex->comp[MODE_OUT];                  comp = &kex->comp[MODE_OUT];
         }          }
         block_size = enc ? enc->block_size : 8;          block_size = enc ? enc->cipher->block_size : 8;
   
         cp = buffer_ptr(&outgoing_packet);          cp = buffer_ptr(&outgoing_packet);
         type = cp[5] & 0xff;          type = cp[5] & 0xff;
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         if (padlen < 4)          if (padlen < 4)
                 padlen += block_size;                  padlen += block_size;
         buffer_append_space(&outgoing_packet, &cp, padlen);          buffer_append_space(&outgoing_packet, &cp, padlen);
         if (enc && enc->type != SSH_CIPHER_NONE) {          if (enc && enc->cipher->number != SSH_CIPHER_NONE) {
                 /* random padding */                  /* random padding */
                 for (i = 0; i < padlen; i++) {                  for (i = 0; i < padlen; i++) {
                         if (i % 4 == 0)                          if (i % 4 == 0)
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                     buffer_len(&outgoing_packet),                      buffer_len(&outgoing_packet),
                     mac->key, mac->key_len                      mac->key, mac->key_len
                 );                  );
                 DBG(debug("done calc HMAC out #%d", seqnr));                  DBG(debug("done calc MAC out #%d", seqnr));
         }          }
         /* encrypt packet and append to output buffer. */          /* encrypt packet and append to output buffer. */
         buffer_append_space(&output, &cp, buffer_len(&outgoing_packet));          buffer_append_space(&output, &cp, buffer_len(&outgoing_packet));
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                         fatal("packet_send2: no KEX");                          fatal("packet_send2: no KEX");
                 if (mac->md != NULL)                  if (mac->md != NULL)
                         mac->enabled = 1;                          mac->enabled = 1;
                 DBG(debug("cipher_set_key_iv send_context"));                  DBG(debug("cipher_init send_context"));
                 cipher_set_key_iv(&send_context, enc->type,                  cipher_init(&send_context, enc->cipher,
                     enc->key, enc->key_len,                      enc->key, enc->cipher->key_len,
                     enc->iv, enc->iv_len);                      enc->iv, enc->cipher->block_size);
                 clear_enc_keys(enc, kex->we_need);                  clear_enc_keys(enc, kex->we_need);
                 if (comp->type != 0 && comp->enabled == 0) {                  if (comp->type != 0 && comp->enabled == 0) {
                         comp->enabled = 1;                          comp->enabled = 1;
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 #endif  #endif
   
         /* Compute packet checksum. */          /* Compute packet checksum. */
         checksum = crc32((unsigned char *) buffer_ptr(&incoming_packet),          checksum = ssh_crc32((unsigned char *) buffer_ptr(&incoming_packet),
             buffer_len(&incoming_packet) - 4);              buffer_len(&incoming_packet) - 4);
   
         /* Skip padding. */          /* Skip padding. */
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                 comp = &kex->comp[MODE_IN];                  comp = &kex->comp[MODE_IN];
         }          }
         maclen = mac && mac->enabled ? mac->mac_len : 0;          maclen = mac && mac->enabled ? mac->mac_len : 0;
         block_size = enc ? enc->block_size : 8;          block_size = enc ? enc->cipher->block_size : 8;
   
         if (packet_length == 0) {          if (packet_length == 0) {
                 /*                  /*
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                     mac->key, mac->key_len                      mac->key, mac->key_len
                 );                  );
                 if (memcmp(macbuf, buffer_ptr(&input), mac->mac_len) != 0)                  if (memcmp(macbuf, buffer_ptr(&input), mac->mac_len) != 0)
                         packet_disconnect("Corrupted HMAC on input.");                          packet_disconnect("Corrupted MAC on input.");
                 DBG(debug("HMAC #%d ok", seqnr));                  DBG(debug("MAC #%d ok", seqnr));
                 buffer_consume(&input, mac->mac_len);                  buffer_consume(&input, mac->mac_len);
         }          }
         if (++seqnr == 0)          if (++seqnr == 0)
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                         fatal("packet_read_poll2: no KEX");                          fatal("packet_read_poll2: no KEX");
                 if (mac->md != NULL)                  if (mac->md != NULL)
                         mac->enabled = 1;                          mac->enabled = 1;
                 DBG(debug("cipher_set_key_iv receive_context"));                  DBG(debug("cipher_init receive_context"));
                 cipher_set_key_iv(&receive_context, enc->type,                  cipher_init(&receive_context, enc->cipher,
                     enc->key, enc->key_len,                      enc->key, enc->cipher->key_len,
                     enc->iv, enc->iv_len);                      enc->iv, enc->cipher->block_size);
                 clear_enc_keys(enc, kex->we_need);                  clear_enc_keys(enc, kex->we_need);
                 if (comp->type != 0 && comp->enabled == 0) {                  if (comp->type != 0 && comp->enabled == 0) {
                         comp->enabled = 1;                          comp->enabled = 1;
Legend:
Removed from v.1.32  
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  Added in v.1.32.2.2