xref: /dragonfly/lib/libcrypt/crypt-sha512.c (revision 6e278935)
1 /*
2  * Copyright (c) 2010
3  * 	The DragonFly Project.  All rights reserved.
4  *
5  * This code is derived from software contributed to The DragonFly Project
6  * by Nolan Lum <nol888@gmail.com>
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  *
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in
16  *    the documentation and/or other materials provided with the
17  *    distribution.
18  * 3. Neither the name of The DragonFly Project nor the names of its
19  *    contributors may be used to endorse or promote products derived
20  *    from this software without specific, prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
23  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
24  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
25  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
26  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
27  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
28  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
29  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
30  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
31  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
32  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 #include <sys/types.h>
37 #include <string.h>
38 #include <sha512.h>
39 #include "crypt.h"
40 
41 /*
42  * New password crypt.
43  */
44 
45 char*
46 crypt_sha512(const char *pw, const char *salt)
47 {
48 	static const char *magic = "$4$"; /* Magic string for this
49 										 * algorithm. Easier to change
50 										 * when factored as constant.
51 										 */
52 	static char         passwd[120], *p;
53 	static const char *sp, *ep;
54 	unsigned char final[SHA512_SIZE];
55 	int sl, i;
56 	SHA512_CTX ctx;
57 	unsigned long l;
58 
59 	/* Refine the salt. */
60 	sp = salt;
61 
62 	/* If it starts with the magic string, then skip that. */
63 	if (!strncmp(sp, magic, strlen(magic)))
64 		sp += strlen(magic);
65 
66 	/* Stop at the first '$', max 8 chars. */
67 	for (ep = sp; *ep && *ep != '$' && ep < (sp + 8); ep++)
68 		continue;
69 
70 	/* Get the actual salt length. */
71 	sl = ep - sp;
72 
73 	SHA512_Init(&ctx);
74 
75 	/* Hash in the password first. */
76 	SHA512_Update(&ctx, pw, strlen(pw));
77 
78 	/* Then the magic string */
79 	SHA512_Update(&ctx, magic, sizeof(magic));
80 
81 	/* Then the raw salt. */
82 	SHA512_Update(&ctx, sp, sl);
83 
84 	/* Finish and create the output string. */
85 	SHA512_Final(final, &ctx);
86 	strcpy(passwd, magic);
87 	strncat(passwd, sp, sl);
88 	strcat(passwd, "$");
89 
90 	p = passwd + strlen(passwd);
91 
92 	/*
93 	 * For-loop form of the algorithm in sha256.c;
94 	 * breaks the final output up into 3cols and then base64's each row.
95 	 */
96 	for (i = 0; i < 20; i++) {
97 		l = (final[i] << 16) | (final[i + 21] << 8) | final[i + 42];
98 		_crypt_to64(p, l, 4); p += 4;
99 	}
100 	l = (final[20] << 16) | (final[41] << 8);
101 	_crypt_to64(p, l, 4); p += 4;
102 	*p = '\0';
103 
104 	/* Clear memory. */
105 	memset(final, 0, sizeof(final));
106 
107 	return (passwd);
108 }
109