2 * This file is part of DisOrder
3 * Copyright (C) 2004, 2006, 2007, 2009, 2013 Richard Kettlewell
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 3 of the License, or
8 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program. If not, see <http://www.gnu.org/licenses/>.
18 /** @file lib/authhash.c @brief The authorization hash */
26 # error No crypto API available
33 /** @brief Structure of algorithm lookup table */
35 /** @brief DisOrder algorithm name */
39 /** @brief gcrypt algorithm ID */
45 /** @brief Algorithm lookup table
47 * We don't use gcry_md_map_name() since that would import gcrypt's API into
48 * the disorder protocol.
50 static const struct algorithm algorithms[] = {
52 { "SHA1", GCRY_MD_SHA1 },
53 { "sha1", GCRY_MD_SHA1 },
54 { "SHA256", GCRY_MD_SHA256 },
55 { "sha256", GCRY_MD_SHA256 },
56 { "SHA384", GCRY_MD_SHA384 },
57 { "sha384", GCRY_MD_SHA384 },
58 { "SHA512", GCRY_MD_SHA512 },
59 { "sha512", GCRY_MD_SHA512 },
63 /** @brief Number of supported algorithms */
64 #define NALGORITHMS (sizeof algorithms / sizeof *algorithms)
66 /** @brief Perform the authorization hash function
67 * @param challenge Pointer to challange
68 * @param nchallenge Size of challenge
69 * @param password Password
70 * @param algo Algorithm to use
71 * @return Hex string or NULL on error
73 * Computes H(challenge|password) and returns it as a newly allocated hex
74 * string, or returns NULL on error.
76 char *authhash(const void *challenge, size_t nchallenge,
77 const char *password, const char *algo) {
85 assert(challenge != 0);
86 assert(password != 0);
88 for(n = 0; n < NALGORITHMS; ++n)
89 if(!strcmp(algo, algorithms[n].name))
94 id = algorithms[n].id;
99 if((e = gcry_md_open(&h, id, 0))) {
100 disorder_error(0, "gcry_md_open: %s", gcry_strerror(e));
105 h = gcry_md_open(id, 0);
107 gcry_md_write(h, password, strlen(password));
108 gcry_md_write(h, challenge, nchallenge);
109 res = hex(gcry_md_read(h, id), gcry_md_get_algo_dlen(id));
115 /** @brief Return non-zero if @p algo is a valid algorithm */
116 int valid_authhash(const char *algo) {
119 for(n = 0; n < NALGORITHMS; ++n)
120 if(!strcmp(algo, algorithms[n].name))