1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 1999 Mark Murray
5 * Copyright (c) 2014 Dag-Erling Sm��rgrav
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY MARK MURRAY 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 MARK MURRAY 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
30#include <sys/types.h>
31
32#include <string.h>
33#include <unistd.h>
34
35#include "crypt.h"
36
37/*
38 * List of supported crypt(3) formats.
39 *
40 * The default algorithm is the last entry in the list (second-to-last
41 * array element since the last is a sentinel).  The reason for placing
42 * the default last rather than first is that DES needs to be at the
43 * bottom for the algorithm guessing logic in crypt(3) to work correctly,
44 * and it needs to be the default for backward compatibility.
45 */
46static const struct crypt_format {
47	const char *name;
48	int (*func)(const char *, const char *, char *);
49	const char *magic;
50} crypt_formats[] = {
51	{ "md5",	crypt_md5,		"$1$"	},
52#ifdef HAS_BLOWFISH
53	{ "blf",	crypt_blowfish,		"$2"	},
54#endif
55	{ "nth",	crypt_nthash,		"$3$"	},
56	{ "sha256",	crypt_sha256,		"$5$"	},
57	{ "sha512",	crypt_sha512,		"$6$"	},
58#ifdef HAS_DES
59	{ "des",	crypt_des,		"_"	},
60#endif
61
62	/* sentinel */
63	{ NULL,		NULL,			NULL	}
64};
65
66static const struct crypt_format *crypt_format =
67    &crypt_formats[(sizeof crypt_formats / sizeof *crypt_formats) - 2];
68
69#define DES_SALT_ALPHABET \
70	"./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
71
72/*
73 * Returns the name of the currently selected format.
74 */
75const char *
76crypt_get_format(void)
77{
78
79	return (crypt_format->name);
80}
81
82/*
83 * Selects the format to use for subsequent crypt(3) invocations.
84 */
85int
86crypt_set_format(const char *format)
87{
88	const struct crypt_format *cf;
89
90	for (cf = crypt_formats; cf->name != NULL; ++cf) {
91		if (strcasecmp(cf->name, format) == 0) {
92			crypt_format = cf;
93			return (1);
94		}
95	}
96	return (0);
97}
98
99/*
100 * Hash the given password with the given salt.  If the salt begins with a
101 * magic string (e.g. "$6$" for sha512), the corresponding format is used;
102 * otherwise, the currently selected format is used.
103 */
104char *
105crypt_r(const char *passwd, const char *salt, struct crypt_data *data)
106{
107	const struct crypt_format *cf;
108	int (*func)(const char *, const char *, char *);
109#ifdef HAS_DES
110	int len;
111#endif
112
113	for (cf = crypt_formats; cf->name != NULL; ++cf)
114		if (cf->magic != NULL && strstr(salt, cf->magic) == salt) {
115			func = cf->func;
116			goto match;
117		}
118#ifdef HAS_DES
119	len = strlen(salt);
120	if ((len == 13 || len == 2) && strspn(salt, DES_SALT_ALPHABET) == len) {
121		func = crypt_des;
122		goto match;
123	}
124#endif
125	func = crypt_format->func;
126match:
127	if (func(passwd, salt, data->__buf) != 0)
128		return (NULL);
129	return (data->__buf);
130}
131
132char *
133crypt(const char *passwd, const char *salt)
134{
135	static struct crypt_data data;
136
137	return (crypt_r(passwd, salt, &data));
138}
139