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/* $OpenBSD: rd_safe.c,v 1.5 1997/12/12 05:30:29 art Exp $ */
/* $KTH: rd_safe.c,v 1.24 1997/04/19 23:18:20 joda Exp $ */
/*
* Copyright (c) 1995, 1996, 1997 Kungliga Tekniska Högskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* 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 the Kungliga Tekniska
* Högskolan and its contributors.
*
* 4. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``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 INSTITUTE OR CONTRIBUTORS 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 "krb_locl.h"
/* application include files */
#include "krb-archaeology.h"
/* Generate two checksums in the given byteorder of the data, one
* new-form and one old-form. It has to be done this way to be
* compatible with the old version of des_quad_cksum.
*/
/* des_quad_chsum-type; 0 == unknown, 1 == new PL10++, 2 == old */
int dqc_type = DES_QUAD_DEFAULT;
void
fixup_quad_cksum(void *start, size_t len, des_cblock *key,
void *new_checksum, void *old_checksum, int little)
{
if (old_checksum == NULL || new_checksum == NULL)
return;
des_quad_cksum((des_cblock*)start, (des_cblock*)new_checksum, len, 2, key);
if(HOST_BYTE_ORDER){
if(little){
memcpy(old_checksum, new_checksum, 16);
}else{
u_int32_t *tmp = (u_int32_t*)new_checksum;
memcpy(old_checksum, new_checksum, 16);
swap_u_16(old_checksum);
swap_u_long(tmp[0]);
swap_u_long(tmp[1]);
swap_u_long(tmp[2]);
swap_u_long(tmp[3]);
}
}else{
if(little){
u_int32_t *tmp = (u_int32_t*)new_checksum;
swap_u_long(tmp[0]);
swap_u_long(tmp[1]);
swap_u_long(tmp[2]);
swap_u_long(tmp[3]);
memcpy(old_checksum, new_checksum, 16);
}else{
u_int32_t tmp[4];
tmp[0] = ((u_int32_t*)new_checksum)[3];
tmp[1] = ((u_int32_t*)new_checksum)[2];
tmp[2] = ((u_int32_t*)new_checksum)[1];
tmp[3] = ((u_int32_t*)new_checksum)[0];
memcpy(old_checksum, tmp, 16);
}
}
}
/*
* krb_rd_safe() checks the integrity of an AUTH_MSG_SAFE message.
* Given the message received, "in", the length of that message,
* "in_length", the "key" to compute the checksum with, and the
* network addresses of the "sender" and "receiver" of the message,
* krb_rd_safe() returns RD_AP_OK if message is okay, otherwise
* some error code.
*
* The message data retrieved from "in" is returned in the structure
* "m_data". The pointer to the application data (m_data->app_data)
* refers back to the appropriate place in "in".
*
* See the file "mk_safe.c" for the format of the AUTH_MSG_SAFE
* message. The structure containing the extracted message
* information, MSG_DAT, is defined in "krb.h".
*/
int32_t
krb_rd_safe(void *in, u_int32_t in_length, des_cblock *key,
struct sockaddr_in *sender, struct sockaddr_in *receiver,
MSG_DAT *m_data)
{
unsigned char *p = (unsigned char*)in, *start;
unsigned char pvno, type;
int little_endian;
struct timeval tv;
u_int32_t src_addr;
int delta_t;
if (p == NULL)
return KFAILURE;
pvno = *p++;
if(pvno != KRB_PROT_VERSION)
return RD_AP_VERSION;
type = *p++;
little_endian = type & 1;
type &= ~1;
if(type != AUTH_MSG_SAFE)
return RD_AP_MSG_TYPE;
start = p;
p += krb_get_int(p, &m_data->app_length, 4, little_endian);
if(m_data->app_length + 31 > in_length)
return RD_AP_MODIFIED;
m_data->app_data = p;
p += m_data->app_length;
m_data->time_5ms = *p++;
p += krb_get_address(p, &src_addr);
if (!krb_equiv(src_addr, sender->sin_addr.s_addr))
return RD_AP_BADD;
p += krb_get_int(p, (u_int32_t *)&m_data->time_sec, 4, little_endian);
m_data->time_sec = lsb_time(m_data->time_sec, sender, receiver);
gettimeofday(&tv, NULL);
delta_t = abs((int)((long) tv.tv_sec - m_data->time_sec));
if (delta_t > CLOCK_SKEW) return RD_AP_TIME;
/*
* caller must check timestamps for proper order and replays, since
* server might have multiple clients each with its own timestamps
* and we don't assume tightly synchronized clocks.
*/
{
unsigned char new_checksum[16];
unsigned char old_checksum[16];
fixup_quad_cksum(start, p - start, key,
new_checksum, old_checksum, little_endian);
if((dqc_type == DES_QUAD_GUESS || dqc_type == DES_QUAD_NEW) &&
memcmp(new_checksum, p, 16) == 0)
dqc_type = DES_QUAD_NEW;
else if((dqc_type == DES_QUAD_GUESS || dqc_type == DES_QUAD_OLD) &&
memcmp(old_checksum, p, 16) == 0)
dqc_type = DES_QUAD_OLD;
else
return RD_AP_MODIFIED;
}
return KSUCCESS;
}
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