chiark / gitweb /
Fiddle with CSS+HTML in effort to get more consistent buttons
[disorder] / lib / authhash.c
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460b9539 1/*
2 * This file is part of DisOrder
1020001c 3 * Copyright (C) 2004, 2006, 2007 Richard Kettlewell
460b9539 4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
18 * USA
19 */
14ad73b9 20/** @file lib/authhash.c @brief The authorization hash */
460b9539 21
05b75f8d 22#include "common.h"
460b9539 23
24#include <stddef.h>
25#include <gcrypt.h>
26
27#include "hex.h"
28#include "log.h"
29#include "authhash.h"
30
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31/** @brief Structure of algorithm lookup table */
32struct algorithm {
33 const char *name;
34 int id;
35};
36
37/** @brief Algorithm lookup table
38 *
39 * We don't use gcry_md_map_name() since that would import gcrypt's API into
40 * the disorder protocol.
41 */
42static const struct algorithm algorithms[] = {
43 { "SHA1", GCRY_MD_SHA1 },
44 { "sha1", GCRY_MD_SHA1 },
45 { "SHA256", GCRY_MD_SHA256 },
46 { "sha256", GCRY_MD_SHA256 },
47 { "SHA384", GCRY_MD_SHA384 },
48 { "sha384", GCRY_MD_SHA384 },
49 { "SHA512", GCRY_MD_SHA512 },
50 { "sha512", GCRY_MD_SHA512 },
51};
52
53/** @brief Number of supported algorithms */
54#define NALGORITHMS (sizeof algorithms / sizeof *algorithms)
460b9539 55
d7b6f0d1 56/** @brief Perform the authorization hash function
57 * @param challenge Pointer to challange
58 * @param nchallenge Size of challenge
59 * @param password Password
637fdea3 60 * @param algo Algorithm to use
d7b6f0d1 61 *
62 * Computes H(challenge|password) and returns it as a newly allocated hex
637fdea3 63 * string, or returns NULL on error.
d7b6f0d1 64 */
460b9539 65const char *authhash(const void *challenge, size_t nchallenge,
637fdea3 66 const char *password, const char *algo) {
460b9539 67 gcrypt_hash_handle h;
68 const char *res;
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69 size_t n;
70 int id;
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71
72 assert(challenge != 0);
73 assert(password != 0);
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74 assert(algo != 0);
75 for(n = 0; n < NALGORITHMS; ++n)
76 if(!strcmp(algo, algorithms[n].name))
77 break;
78 if(n >= NALGORITHMS)
79 return NULL;
80 id = algorithms[n].id;
460b9539 81#if HAVE_GCRY_ERROR_T
82 {
83 gcry_error_t e;
84
637fdea3 85 if((e = gcry_md_open(&h, id, 0))) {
460b9539 86 error(0, "gcry_md_open: %s", gcry_strerror(e));
87 return 0;
88 }
89 }
90#else
637fdea3 91 h = gcry_md_open(id, 0);
460b9539 92#endif
93 gcry_md_write(h, password, strlen(password));
94 gcry_md_write(h, challenge, nchallenge);
637fdea3 95 res = hex(gcry_md_read(h, id), gcry_md_get_algo_dlen(id));
460b9539 96 gcry_md_close(h);
97 return res;
98}
99
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100/** @brief Return non-zero if @p algo is a valid algorithm */
101int valid_authhash(const char *algo) {
102 size_t n;
103
104 for(n = 0; n < NALGORITHMS; ++n)
105 if(!strcmp(algo, algorithms[n].name))
106 return 1;
107 return 0;
108}
109
460b9539 110/*
111Local Variables:
112c-basic-offset:2
113comment-column:40
114fill-column:79
115End:
116*/