cryb-otp/sbin/otpradiusd/auth.c
2022-09-16 15:26:25 +02:00

104 lines
2.8 KiB
C

/*-
* Copyright (c) 2018 The University of Oslo
* 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. 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 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 AUTHOR 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 "cryb/impl.h"
#include <sys/socket.h>
#include <arpa/inet.h>
#include <err.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <cryb/assert.h>
#include <cryb/md5.h>
#include <cryb/memset_s.h>
#include "otpradiusd.h"
const char *rad_secret;
size_t rad_secret_len;
void
auth_encode(const uint8_t *nonce, const uint8_t *pt,
uint8_t *ct, size_t len)
{
md5_ctx ctx, sctx;
uint8_t stream[16];
const uint8_t *key;
unsigned int i;
assert(len % 16 == 0);
md5_init(&ctx);
md5_update(&ctx, rad_secret, rad_secret_len);
sctx = ctx;
key = nonce;
while (len >= 16) {
ctx = sctx;
md5_update(&ctx, key, 16);
md5_final(&ctx, stream);
for (i = 0; i < 16; ++i)
ct[i] = pt[i] ^ stream[i];
key = ct;
ct += 16;
pt += 16;
len -= 16;
}
memset_s(&sctx, sizeof sctx, 0, sizeof sctx);
}
void
auth_decode(const uint8_t *nonce, const uint8_t *ct,
uint8_t *pt, size_t len)
{
md5_ctx ctx, sctx;
uint8_t stream[16];
const uint8_t *key;
unsigned int i;
assert(len % 16 == 0);
md5_init(&ctx);
md5_update(&ctx, rad_secret, rad_secret_len);
sctx = ctx;
key = nonce;
while (len >= 16) {
ctx = sctx;
md5_update(&ctx, key, 16);
md5_final(&ctx, stream);
for (i = 0; i < 16; ++i)
pt[i] = ct[i] ^ stream[i];
key = ct;
pt += 16;
ct += 16;
len -= 16;
}
memset_s(&sctx, sizeof sctx, 0, sizeof sctx);
}