crypt.c revision 272830 
1/*-
2 * Copyright (c) 1999 Mark Murray
3 * Copyright (c) 2014 Dag-Erling Sm��rgrav
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY MARK MURRAY AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL MARK MURRAY OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28#include <sys/cdefs.h>
29__FBSDID("$FreeBSD: head/lib/libcrypt/crypt.c 272830 2014-10-09 16:45:11Z des $");
30
31#include <sys/types.h>
32
33#include <libutil.h>
34#include <string.h>
35#include <unistd.h>
36
37#include "crypt.h"
38
39/*
40 * List of supported crypt(3) formats.
41 *
42 * The default algorithm is the last entry in the list (second-to-last
43 * array element since the last is a sentinel).  The reason for placing
44 * the default last rather than first is that DES needs to be at the
45 * bottom for the algorithm guessing logic in crypt(3) to work correctly,
46 * and it needs to be the default for backward compatibility.
47 */
48static const struct crypt_format {
49	const char *const name;
50	char *(*const func)(const char *, const char *);
51	const char *const magic;
52} crypt_formats[] = {
53	{ "md5",	crypt_md5,		"$1$"	},
54#ifdef HAS_BLOWFISH
55	{ "blf",	crypt_blowfish,		"$2"	},
56#endif
57	{ "nth",	crypt_nthash,		"$3$"	},
58	{ "sha256",	crypt_sha256,		"$5$"	},
59	{ "sha512",	crypt_sha512,		"$6$"	},
60#ifdef HAS_DES
61	{ "des",	crypt_des,		"_"	},
62#endif
63
64	/* sentinel */
65	{ NULL,		NULL,			NULL	}
66};
67
68static const struct crypt_format *crypt_format =
69    &crypt_formats[(sizeof crypt_formats / sizeof *crypt_formats) - 2];
70
71#define DES_SALT_ALPHABET \
72	"./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
73
74/*
75 * Returns the name of the currently selected format.
76 */
77const char *
78crypt_get_format(void)
79{
80
81	return (crypt_format->name);
82}
83
84/*
85 * Selects the format to use for subsequent crypt(3) invocations.
86 */
87int
88crypt_set_format(const char *format)
89{
90	const struct crypt_format *cf;
91
92	for (cf = crypt_formats; cf->name != NULL; ++cf) {
93		if (strcasecmp(cf->name, format) == 0) {
94			crypt_format = cf;
95			return (1);
96		}
97	}
98	return (0);
99}
100
101/*
102 * Hash the given password with the given salt.  If the salt begins with a
103 * magic string (e.g. "$6$" for sha512), the corresponding format is used;
104 * otherwise, the currently selected format is used.
105 */
106char *
107crypt(const char *passwd, const char *salt)
108{
109	const struct crypt_format *cf;
110#ifdef HAS_DES
111	int len;
112#endif
113
114	for (cf = crypt_formats; cf->name != NULL; ++cf)
115		if (cf->magic != NULL && strstr(salt, cf->magic) == salt)
116			return (cf->func(passwd, salt));
117#ifdef HAS_DES
118	len = strlen(salt);
119	if ((len == 13 || len == 2) && strspn(salt, DES_SALT_ALPHABET) == len)
120		return (crypt_des(passwd, salt));
121#endif
122	return (crypt_format->func(passwd, salt));
123}
124