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/*
* Copyright 1997 Niels Provos <provos@physnet.uni-hamburg.de>
* 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Niels Provos.
* 4. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* 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.
*/
/*
* validity.c:
* validity verification
*/
#ifndef lint
static char rcsid[] = "$Id: validity.c,v 1.1 1998/11/14 23:37:30 deraadt Exp $";
#endif
#define _VALIDITY_C_
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <md5.h>
#include <sha1.h>
#include "config.h"
#include "scheme.h"
#include "exchange.h"
#include "errlog.h"
#include "state.h"
#include "attributes.h"
#include "validity.h"
#include "identity.h"
#include "buffer.h"
int valsign(struct stateob *st, struct idxform *hash, u_int8_t *signature,
u_int8_t *packet, u_int16_t psize);
int valverify(struct stateob *st, struct idxform *hash, u_int8_t *signature,
u_int8_t *packet, u_int16_t psize);
u_int16_t
get_validity_verification_size(struct stateob *st)
{
switch(ntohs(*((u_int16_t *)st->scheme))) {
case DH_G_2_MD5:
case DH_G_3_MD5:
case DH_G_5_MD5:
case DH_G_2_DES_MD5:
case DH_G_3_DES_MD5:
case DH_G_5_DES_MD5:
return (128/8)+2; /* Two octets for varpre size */
case DH_G_2_3DES_SHA1:
case DH_G_3_3DES_SHA1:
case DH_G_5_3DES_SHA1:
return (160/8)+2;
default:
log_error(0, "validitiy.c: Unknown exchange scheme: %d\n",
*((u_int16_t *)st->scheme));
return 0;
}
}
int
create_validity_verification(struct stateob *st, u_int8_t *buffer,
u_int8_t *packet, u_int16_t size)
{
struct idxform *hash;
switch(ntohs(*((u_int16_t *)st->scheme))) {
case DH_G_2_MD5:
case DH_G_3_MD5:
case DH_G_5_MD5:
case DH_G_2_DES_MD5:
case DH_G_3_DES_MD5:
case DH_G_5_DES_MD5:
hash = get_hash(HASH_MD5);
break;
case DH_G_2_3DES_SHA1:
case DH_G_3_3DES_SHA1:
case DH_G_5_3DES_SHA1:
hash = get_hash(HASH_SHA1);
break;
default:
log_error(0, "validity.c: Unknown exchange scheme: %d\n",
*((u_int16_t *)st->scheme));
return 0;
}
if(valsign(st, hash, buffer+2, packet, size)) {
/* Create varpre number from digest */
buffer[0] = (hash->hashsize >> 5) & 0xFF;
buffer[1] = (hash->hashsize << 3) & 0xFF;
}
state_save_verification(st, buffer, hash->hashsize+2);
return hash->hashsize+2;
}
int
verify_validity_verification(struct stateob *st, u_int8_t *buffer,
u_int8_t *packet, u_int16_t size)
{
struct idxform *hash;
switch(ntohs(*((u_int16_t *)st->scheme))) {
case DH_G_2_MD5:
case DH_G_3_MD5:
case DH_G_5_MD5:
case DH_G_2_DES_MD5:
case DH_G_3_DES_MD5:
case DH_G_5_DES_MD5:
if (varpre2octets(buffer) != 18)
return 0;
hash = get_hash(HASH_MD5);
break;
case DH_G_2_3DES_SHA1:
case DH_G_3_3DES_SHA1:
case DH_G_5_3DES_SHA1:
if (varpre2octets(buffer) != 22)
return 0;
hash = get_hash(HASH_SHA1);
break;
default:
log_error(0, "validity.c: Unknown exchange scheme: %d\n",
*((u_int16_t *)st->scheme));
return 0;
}
state_save_verification(st, buffer, hash->hashsize+2);
return valverify(st, hash, buffer+2, packet, size);
}
int
valsign(struct stateob *st, struct idxform *hash, u_int8_t *signature,
u_int8_t *packet, u_int16_t psize)
{
u_int8_t key[HASH_MAX];
u_int16_t keylen = HASH_MAX;
create_verification_key(st, key, &keylen, 1); /* Owner direction */
hash->Init(hash->ctx);
hash->Update(hash->ctx, key, keylen);
hash->Update(hash->ctx, st->icookie, COOKIE_SIZE);
hash->Update(hash->ctx, st->rcookie, COOKIE_SIZE);
packet += 2*COOKIE_SIZE; psize -= 2*COOKIE_SIZE;
hash->Update(hash->ctx, packet, 4 + SPI_SIZE);
hash->Update(hash->ctx, st->oSPIidentver, st->oSPIidentversize);
hash->Update(hash->ctx, st->uSPIidentver, st->uSPIidentversize);
packet += 4 + SPI_SIZE + hash->hashsize + 2;
psize -= 4 + SPI_SIZE + hash->hashsize + 2;
hash->Update(hash->ctx, packet, psize);
/* Data fill */
hash->Final(NULL, hash->ctx);
hash->Update(hash->ctx, key, keylen);
hash->Final(signature, hash->ctx);
return hash->hashsize;
}
/* We assume that the verification field is zeroed */
int
valverify(struct stateob *st, struct idxform *hash, u_int8_t *signature,
u_int8_t *packet, u_int16_t psize)
{
u_int8_t digest[HASH_MAX];
u_int8_t key[HASH_MAX];
u_int16_t keylen = HASH_MAX;
create_verification_key(st, key, &keylen, 0); /* User direction */
hash->Init(hash->ctx);
hash->Update(hash->ctx, key, keylen);
hash->Update(hash->ctx, st->icookie, COOKIE_SIZE);
hash->Update(hash->ctx, st->rcookie, COOKIE_SIZE);
packet += 2*COOKIE_SIZE; psize -= 2*COOKIE_SIZE;
hash->Update(hash->ctx, packet, 4 + SPI_SIZE);
hash->Update(hash->ctx, st->uSPIidentver, st->uSPIidentversize);
hash->Update(hash->ctx, st->oSPIidentver, st->oSPIidentversize);
packet += 4 + SPI_SIZE + hash->hashsize + 2;
psize -= 4 + SPI_SIZE + hash->hashsize + 2;
hash->Update(hash->ctx, packet, psize);
/* Data fill */
hash->Final(NULL, hash->ctx);
hash->Update(hash->ctx, key, keylen);
hash->Final(digest, hash->ctx);
return !bcmp(digest,signature,hash->hashsize);
}
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