mirror of
https://github.com/cryb-to/cryb-to.git
synced 2024-12-22 12:31:07 +00:00
128 lines
3.5 KiB
C
128 lines
3.5 KiB
C
/*-
|
|
* Copyright (c) 2012-2013 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 <stdint.h>
|
|
#include <string.h>
|
|
|
|
#include <cryb/hmac_sha1.h>
|
|
#include <cryb/oath.h>
|
|
|
|
#define StToNum(St) (St)
|
|
|
|
static uint32_t
|
|
DT(const uint8_t *String)
|
|
{
|
|
uint8_t OffsetBits;
|
|
int Offset;
|
|
uint32_t P;
|
|
|
|
OffsetBits = String[19] & 0x0f;
|
|
Offset = StToNum(OffsetBits);
|
|
P = (uint32_t)String[Offset + 0] << 24 |
|
|
(uint32_t)String[Offset + 1] << 16 |
|
|
(uint32_t)String[Offset + 2] << 8 |
|
|
(uint32_t)String[Offset + 3];
|
|
return (P & 0x7fffffffUL);
|
|
}
|
|
|
|
unsigned int
|
|
oath_hotp(const uint8_t *K, size_t Klen, uint64_t seq, unsigned int Digit)
|
|
{
|
|
hmac_sha1_ctx ctx;
|
|
uint8_t C[8];
|
|
uint8_t HS[20];
|
|
uint32_t Sbits, Snum;
|
|
unsigned int mod, D;
|
|
|
|
for (int i = 7; i >= 0; --i) {
|
|
C[i] = seq & 0xff;
|
|
seq >>= 8;
|
|
}
|
|
|
|
/* HS = HMAC-SHA-1(K,C) */
|
|
hmac_sha1_init(&ctx, K, Klen);
|
|
hmac_sha1_update(&ctx, (const uint8_t *)&C, sizeof C);
|
|
hmac_sha1_final(&ctx, HS);
|
|
|
|
Sbits = DT(HS);
|
|
Snum = StToNum(Sbits);
|
|
for (mod = 1; Digit > 0; --Digit)
|
|
mod *= 10;
|
|
D = Snum % mod;
|
|
return (D);
|
|
}
|
|
|
|
/*
|
|
* Computes the current code for the given key and advances the counter.
|
|
*/
|
|
unsigned int
|
|
oath_hotp_current(struct oath_key *k)
|
|
{
|
|
unsigned int code;
|
|
|
|
if (k == NULL)
|
|
return (-1);
|
|
if (k->mode != om_hotp)
|
|
return (-1);
|
|
if (k->counter == UINT64_MAX)
|
|
return (-1);
|
|
code = oath_hotp(k->key, k->keylen, k->counter, k->digits);
|
|
k->counter += 1;
|
|
return (code);
|
|
}
|
|
|
|
/*
|
|
* Compares the code provided by the user with expected values within a
|
|
* given window. Returns 1 if there was a match, 0 if not, and -1 if an
|
|
* error occurred. Also advances the counter if there was a match.
|
|
*/
|
|
int
|
|
oath_hotp_match(struct oath_key *k, unsigned int response, int window)
|
|
{
|
|
unsigned int code;
|
|
|
|
if (k == NULL)
|
|
return (-1);
|
|
if (window < 1)
|
|
return (-1);
|
|
if (k->mode != om_hotp)
|
|
return (-1);
|
|
if (k->counter >= UINT64_MAX - window)
|
|
return (-1);
|
|
for (int i = 0; i < window; ++i) {
|
|
code = oath_hotp(k->key, k->keylen, k->counter + i, k->digits);
|
|
if (code == response && !k->dummy) {
|
|
k->counter = k->counter + i;
|
|
return (1);
|
|
}
|
|
}
|
|
return (0);
|
|
}
|