source: openpam/trunk/modules/pam_oath/oath_totp.c @ 643

Last change on this file since 643 was 643, checked in by Dag-Erling Smørgrav, 8 years ago
  • Add a provisional API for computing the current HOTP or TOTP code.
  • Add a provisional API for matching a user response.
  • Add a provisional API for generating a dummy key. When one of the matching functions recognizes a dummy key, it will go through the motions but never report a match.
  • Property svn:eol-style set to native
  • Property svn:keywords set to Id
File size: 2.6 KB
Line 
1/*-
2 * Copyright (c) 2012-2013 Universitetet i Oslo
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. The name of the author may not be used to endorse or promote
14 *    products derived from this software without specific prior written
15 *    permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * $Id: oath_totp.c 643 2013-03-05 15:24:00Z des $
30 */
31
32#ifdef HAVE_CONFIG_H
33# include "config.h"
34#endif
35
36#include <stdint.h>
37#include <string.h>
38#include <time.h>
39
40#include "oath.h"
41
42#define TOTP_TIME_STEP 30
43
44unsigned int
45oath_totp(const uint8_t *K, size_t Klen, unsigned int Digit)
46{
47        time_t now;
48
49        time(&now);
50        return (oath_hotp(K, Klen, now / TOTP_TIME_STEP, Digit));
51}
52
53unsigned int
54oath_totp_current(const struct oath_key *k)
55{
56        unsigned int code;
57        uint64_t seq;
58
59        if (k == NULL)
60                return (-1);
61        if (k->mode != om_totp)
62                return (-1);
63        if (k->timestep == 0)
64                return (-1);
65        seq = time(NULL) / k->timestep;
66        code = oath_hotp(k->key, k->keylen, seq, k->digits);
67        return (code);
68}
69
70int
71oath_totp_match(const struct oath_key *k, unsigned int response, int window)
72{
73        unsigned int code;
74        uint64_t seq;
75        int dummy;
76
77        if (k == NULL)
78                return (-1);
79        if (window < 1)
80                return (-1);
81        if (k->mode != om_totp)
82                return (-1);
83        if (k->timestep == 0)
84                return (-1);
85        seq = time(NULL) / k->timestep;
86        dummy = (memcmp(k->label, DUMMY_LABEL, DUMMY_LABELLEN) == 0);
87        for (int i = -window; i <= window; ++i) {
88                code = oath_hotp(k->key, k->keylen, seq + i, k->digits);
89                if (code == response && !dummy)
90                        return (1);
91        }
92        return (0);
93}
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