xref: /freebsd/lib/libcrypt/crypt.c (revision 6574b8ed19b093f0af09501d2c9676c28993cb97)
1 /*-
2  * Copyright (c) 1999 Mark Murray
3  * Copyright (c) 2014 Dag-Erling Smørgrav
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("$FreeBSD$");
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.  The first element in the list will
41  * be the default.
42  */
43 static const struct crypt_format {
44 	const char *const name;
45 	char *(*const func)(const char *, const char *);
46 	const char *const magic;
47 } crypt_formats[] = {
48 	/* default format */
49 	{ "sha512",	crypt_sha512,		"$6$"	},
50 
51 	/* other supported formats */
52 	{ "md5",	crypt_md5,		"$1$"	},
53 #ifdef HAS_BLOWFISH
54 	{ "blf",	crypt_blowfish,		"$2"	},
55 #endif
56 	{ "nth",	crypt_nthash,		"$3$"	},
57 	{ "sha256",	crypt_sha256,		"$5$"	},
58 #ifdef HAS_DES
59 	{ "des",	crypt_des,		"_"	},
60 #endif
61 
62 	/* sentinel */
63 	{ NULL,		NULL,			NULL	}
64 };
65 
66 static const struct crypt_format *crypt_format = &crypt_formats[0];
67 
68 #define DES_SALT_ALPHABET \
69 	"./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
70 
71 /*
72  * Returns the name of the currently selected format.
73  */
74 const char *
75 crypt_get_format(void)
76 {
77 
78 	return (crypt_format->name);
79 }
80 
81 /*
82  * Selects the format to use for subsequent crypt(3) invocations.
83  */
84 int
85 crypt_set_format(const char *format)
86 {
87 	const struct crypt_format *cf;
88 
89 	for (cf = crypt_formats; cf->name != NULL; ++cf) {
90 		if (strcasecmp(cf->name, format) == 0) {
91 			crypt_format = cf;
92 			return (1);
93 		}
94 	}
95 	return (0);
96 }
97 
98 /*
99  * Hash the given password with the given salt.  If the salt begins with a
100  * magic string (e.g. "$6$" for sha512), the corresponding format is used;
101  * otherwise, the currently selected format is used.
102  */
103 char *
104 crypt(const char *passwd, const char *salt)
105 {
106 	const struct crypt_format *cf;
107 #ifdef HAS_DES
108 	int len;
109 #endif
110 
111 	for (cf = crypt_formats; cf->name != NULL; ++cf)
112 		if (cf->magic != NULL && strstr(salt, cf->magic) == salt)
113 			return (cf->func(passwd, salt));
114 #ifdef HAS_DES
115 	len = strlen(salt);
116 	if ((len == 13 || len == 2) && strspn(salt, DES_SALT_ALPHABET) == len)
117 		return (crypt_des(passwd, salt));
118 #endif
119 	return (crypt_format->func(passwd, salt));
120 }
121