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/* $KTH: rd_priv.c,v 1.24 1997/05/14 17:53:29 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 "lsb_addr_comp.h"
/*
* krb_rd_priv() decrypts and checks the integrity of an
* AUTH_MSG_PRIVATE message. Given the message received, "in",
* the length of that message, "in_length", the key "schedule"
* and "key", and the network addresses of the
* "sender" and "receiver" of the message, krb_rd_safe() returns
* RD_AP_OK if the message is okay, otherwise some error code.
*
* The message data retrieved from "in" are 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_priv.c" for the format of the AUTH_MSG_PRIVATE
* message. The structure containing the extracted message
* information, MSG_DAT, is defined in "krb.h".
*/
int32_t
krb_rd_priv(void *in, u_int32_t in_length,
struct des_ks_struct *schedule, des_cblock *key,
struct sockaddr_in *sender, struct sockaddr_in *receiver,
MSG_DAT *m_data)
{
unsigned char *p = (unsigned char*)in;
int little_endian;
u_int32_t clen;
struct timeval tv;
u_int32_t src_addr;
int delta_t;
unsigned char pvno, type;
pvno = *p++;
if(pvno != KRB_PROT_VERSION)
return RD_AP_VERSION;
type = *p++;
little_endian = type & 1;
type &= ~1;
p += krb_get_int(p, &clen, 4, little_endian);
if(clen + 2 > in_length)
return RD_AP_MODIFIED;
des_pcbc_encrypt((des_cblock*)p, (des_cblock*)p, clen,
schedule, key, DES_DECRYPT);
p += krb_get_int(p, &m_data->app_length, 4, little_endian);
if(m_data->app_length + 17 > 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);
/* check the time integrity of the msg */
delta_t = abs((int)((long) tv.tv_sec - m_data->time_sec));
if (delta_t > CLOCK_SKEW)
return RD_AP_TIME;
if (krb_debug)
krb_warning("\ndelta_t = %d", (int) delta_t);
/*
* 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.
*/
return KSUCCESS;
}
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