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/* $OpenBSD: mk_safe.c,v 1.5 1997/12/12 05:30:28 art Exp $ */
/* $KTH: mk_safe.c,v 1.21 1997/04/19 23:18:03 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"
/* from rd_safe.c */
extern int dqc_type;
void fixup_quad_cksum(void*, size_t, des_cblock*, void*, void*, int);
/*
* krb_mk_safe() constructs an AUTH_MSG_SAFE message. It takes some
* user data "in" of "length" bytes and creates a packet in "out"
* consisting of the user data, a timestamp, and the sender's network
* address, followed by a checksum computed on the above, using the
* given "key". The length of the resulting packet is returned.
*
* The "out" packet consists of:
*
* Size Variable Field
* ---- -------- -----
*
* 1 byte KRB_PROT_VERSION protocol version number
* 1 byte AUTH_MSG_SAFE | message type plus local
* HOST_BYTE_ORDER byte order in low bit
*
* ===================== begin checksum ================================
*
* 4 bytes length length of user data
* length in user data
* 1 byte msg_time_5ms timestamp milliseconds
* 4 bytes sender->sin.addr.s_addr sender's IP address
*
* 4 bytes msg_time_sec or timestamp seconds with
* -msg_time_sec direction in sign bit
*
* ======================= end checksum ================================
*
* 16 bytes big_cksum quadratic checksum of
* above using "key"
*/
int32_t
krb_mk_safe(void *in, void *out, u_int32_t length, des_cblock *key,
struct sockaddr_in *sender, struct sockaddr_in *receiver)
{
unsigned char * p = (unsigned char*)out;
struct timeval tv;
unsigned char *start;
u_int32_t src_addr;
if (p == NULL)
return 0;
p += krb_put_int(KRB_PROT_VERSION, p, 1);
p += krb_put_int(AUTH_MSG_SAFE, p, 1);
start = p;
p += krb_put_int(length, p, 4);
memcpy(p, in, length);
p += length;
gettimeofday(&tv, NULL);
*p++ = tv.tv_usec/5000; /* 5ms */
src_addr = sender->sin_addr.s_addr;
p += krb_put_address(src_addr, p);
p += krb_put_int(lsb_time(tv.tv_sec, sender, receiver), p, 4);
{
/* We are faking big endian mode, so we need to fix the
* checksum (that is byte order dependent). We always send a
* checksum of the new type, unless we know that we are
* talking to an old client (this requires a call to
* krb_rd_safe first).
*/
unsigned char new_checksum[16];
unsigned char old_checksum[16];
fixup_quad_cksum(start, p - start, key, new_checksum, old_checksum, 0);
if((dqc_type == DES_QUAD_GUESS && DES_QUAD_DEFAULT == DES_QUAD_OLD) ||
dqc_type == DES_QUAD_OLD)
memcpy(p, old_checksum, 16);
else
memcpy(p, new_checksum, 16);
}
p += 16;
return p - (unsigned char*)out;
}
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