source: openpam/trunk/modules/pam_oath/oath.h @ 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: 4.0 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.h 643 2013-03-05 15:24:00Z des $
30 */
31
32#ifndef OATH_H_INCLUDED
33#define OATH_H_INCLUDED
34
35/*
36 * Default time step for TOTP: 30 seconds.
37 */
38#define OATH_DEF_TIMESTEP       30
39
40/*
41 * Maximum time step for TOTP: 10 minutes, which RFC 6238 cites as an
42 * example of an unreasonably large time step.
43 */
44#define OATH_MAX_TIMESTEP       600
45
46/*
47 * Maximum key length in bytes.  HMAC has a 64-byte block size; if the key
48 * K is longer than that, HMAC derives a new key K' = H(K).
49 */
50#define OATH_MAX_KEYLEN         64
51
52/* estimate of output length for base32 encoding / decoding */
53#define base32_enclen(l) (size_t)(((l + 4) / 5) * 8)
54#define base32_declen(l) (size_t)(((l + 7) / 8) * 5)
55
56/* base32 encoding / decoding */
57int base32_enc(const uint8_t *, size_t, char *, size_t *);
58int base32_dec(const char *, size_t, uint8_t *, size_t *);
59
60/* estimate of output length for base64 encoding / decoding */
61#define base64_enclen(l) (size_t)(((l + 2) / 3) * 4)
62#define base64_declen(l) (size_t)(((l + 3) / 4) * 3)
63
64/* base64 encoding / decoding */
65int base64_enc(const uint8_t *, size_t, char *, size_t *);
66int base64_dec(const char *, size_t, uint8_t *, size_t *);
67
68/* mode: hotp (event mode) or totp (time-synch mode) */
69enum oath_mode { om_undef, om_hotp, om_totp };
70
71/* hash function */
72enum oath_hash { oh_undef, oh_sha1, oh_sha256, oh_sha512, oh_md5 };
73
74/* key structure */
75struct oath_key {
76        /* mode and parameters */
77        enum oath_mode   mode;
78        unsigned int     digits;
79        uint64_t         counter;
80        unsigned int     timestep; /* in seconds */
81
82        /* hash algorithm */
83        enum oath_hash   hash;
84
85        /* label */
86        size_t           labellen; /* bytes incl. NUL */
87        char            *label;
88
89        /* key */
90        size_t           keylen; /* bytes */
91        uint8_t         *key;
92
93        /* buffer for label + NUL + key */
94        size_t           datalen; /* bytes */
95        uint8_t          data[];
96};
97
98struct oath_key *oath_key_alloc(size_t);
99void oath_key_free(struct oath_key *);
100struct oath_key *oath_key_from_uri(const char *);
101struct oath_key *oath_key_from_file(const char *);
102char *oath_key_to_uri(const struct oath_key *);
103
104#define DUMMY_LABEL     ("oath-dummy-key")
105#define DUMMY_LABELLEN  (sizeof DUMMY_LABEL)
106#define DUMMY_KEYLEN    80
107
108struct oath_key *oath_dummy_key(enum oath_mode, enum oath_hash, unsigned int);
109
110unsigned int oath_hotp(const uint8_t *, size_t, uint64_t, unsigned int);
111int oath_hotp_current(struct oath_key *);
112int oath_hotp_match(struct oath_key *, unsigned int, int);
113
114unsigned int oath_totp(const uint8_t *, size_t, unsigned int);
115int oath_totp_match(const struct oath_key *, unsigned int, int);
116unsigned int oath_totp_current(const struct oath_key *);
117
118#endif
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