xref: /titanic_51/usr/src/lib/crypt_modules/sha256/crypt_sha.c (revision 43d5cd3d2ec5c3a1e2b2a9155ae4042c14a99011) 
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 #pragma ident	"%Z%%M%	%I%	%E% SMI"
27 
28 /*
29  * Portions of this code from crypt_bsdmd5.so (bsdmd5.c) :
30  * ----------------------------------------------------------------------------
31  * "THE BEER-WARE LICENSE" (Revision 42):
32  * <phk@login.dknet.dk> wrote this file.  As long as you retain this notice you
33  * can do whatever you want with this stuff. If we meet some day, and you think
34  * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
35  * ----------------------------------------------------------------------------
36  *
37  * $FreeBSD: crypt.c,v 1.5 1996/10/14 08:34:02 phk Exp $
38  *
39  */
40 
41 /*
42  * Implements the specification from:
43  *
44  * From http://people.redhat.com/drepper/SHA-crypt.txt
45  *
46  * Portions of the code taken from inspired by or verified against the
47  * source in the above document which is licensed as:
48  *
49  * "Released into the Public Domain by Ulrich Drepper <drepper@redhat.com>."
50  */
51 
52 
53 #include <sys/types.h>
54 #include <sys/stat.h>
55 #include <sys/sysmacros.h>
56 #include <fcntl.h>
57 #include <unistd.h>
58 #include <string.h>
59 #include <stdio.h>
60 #include <errno.h>
61 #include <stdlib.h>
62 #include <alloca.h>
63 
64 #include <sha2.h>
65 #include <crypt.h>
66 
67 #define	MAX_SALT_LEN	16
68 #define	ROUNDS_DEFAULT	5000
69 #define	ROUNDS_MIN	1000
70 #define	ROUNDS_MAX	999999999
71 
72 #ifdef CRYPT_SHA256
73 
74 #define	DIGEST_CTX	SHA256_CTX
75 #define	DIGESTInit	SHA256Init
76 #define	DIGESTUpdate	SHA256Update
77 #define	DIGESTFinal	SHA256Final
78 #define	DIGEST_LEN	SHA256_DIGEST_LENGTH
79 #define	MIXCHARS	32
80 static const char crypt_alg_magic[] = "$5$";
81 
82 #elif CRYPT_SHA512
83 
84 #define	DIGEST_CTX	SHA512_CTX
85 #define	DIGESTInit	SHA512Init
86 #define	DIGESTUpdate	SHA512Update
87 #define	DIGESTFinal	SHA512Final
88 #define	DIGEST_LEN	SHA512_DIGEST_LENGTH
89 #define	MIXCHARS	64
90 static const char crypt_alg_magic[] = "$6$";
91 
92 #else
93 #error	"One of CRYPT_256 or CRYPT_512 must be defined"
94 #endif
95 
96 static const int crypt_alg_magic_len = sizeof (crypt_alg_magic) - 1;
97 static const char rounds_prefix[] = "rounds=";
98 
99 
100 static uchar_t b64t[] =		/* 0 ... 63 => ascii - 64 */
101 	"./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
102 
103 #define	b64_from_24bit(B2, B1, B0, N) \
104 { \
105 	uint_t w = ((B2) << 16) | ((B1) << 8) | (B0); \
106 	int n = (N); \
107 	while (--n >= 0 && ctbufflen > 0) { \
108 		*p++ = b64t[w & 0x3f]; \
109 		w >>= 6; \
110 		ctbufflen--; \
111 	} \
112 }
113 
114 static void
115 to64(char *s, uint64_t v, int n)
116 {
117 	while (--n >= 0) {
118 		*s++ = b64t[v&0x3f];
119 		v >>= 6;
120 	}
121 }
122 
123 char *
124 crypt_genhash_impl(char *ctbuffer,
125 	    size_t ctbufflen,
126 	    const char *plaintext,
127 	    const char *switchsalt,
128 	    const char **params)
129 {
130 	int salt_len, plaintext_len, i;
131 	char *salt;
132 	uchar_t A[DIGEST_LEN];
133 	uchar_t B[DIGEST_LEN];
134 	uchar_t DP[DIGEST_LEN];
135 	uchar_t DS[DIGEST_LEN];
136 	DIGEST_CTX ctxA, ctxB, ctxC, ctxDP, ctxDS;
137 	int rounds = ROUNDS_DEFAULT;
138 	boolean_t custom_rounds = B_FALSE;
139 	char *p;
140 	char *P, *Pp;
141 	char *S, *Sp;
142 
143 	/* Refine the salt */
144 	salt = (char *)switchsalt;
145 
146 	/* skip our magic string */
147 	if (strncmp((char *)salt, crypt_alg_magic, crypt_alg_magic_len) == 0) {
148 		salt += crypt_alg_magic_len;
149 	}
150 
151 	if (strncmp(salt, rounds_prefix, sizeof (rounds_prefix) - 1) == 0) {
152 		char *num = salt + sizeof (rounds_prefix) - 1;
153 		char *endp;
154 		ulong_t srounds = strtoul(num, &endp, 10);
155 		if (*endp == '$') {
156 			salt = endp + 1;
157 			rounds = MAX(ROUNDS_MIN, MIN(srounds, ROUNDS_MAX));
158 			custom_rounds = B_TRUE;
159 		}
160 	}
161 
162 	salt_len = MIN(strcspn(salt, "$"), MAX_SALT_LEN);
163 	plaintext_len = strlen(plaintext);
164 
165 	/* 1. */
166 	DIGESTInit(&ctxA);
167 
168 	/* 2. The password first, since that is what is most unknown */
169 	DIGESTUpdate(&ctxA, plaintext, plaintext_len);
170 
171 	/* 3. Then the raw salt */
172 	DIGESTUpdate(&ctxA, salt, salt_len);
173 
174 	/* 4. - 8. */
175 	DIGESTInit(&ctxB);
176 	DIGESTUpdate(&ctxB, plaintext, plaintext_len);
177 	DIGESTUpdate(&ctxB, salt, salt_len);
178 	DIGESTUpdate(&ctxB, plaintext, plaintext_len);
179 	DIGESTFinal(B, &ctxB);
180 
181 	/* 9. - 10. */
182 	for (i = plaintext_len; i > MIXCHARS; i -= MIXCHARS)
183 		DIGESTUpdate(&ctxA, B, MIXCHARS);
184 	DIGESTUpdate(&ctxA, B, i);
185 
186 	/* 11. */
187 	for (i = plaintext_len; i > 0; i >>= 1) {
188 		if ((i & 1) != 0) {
189 			DIGESTUpdate(&ctxA, B, MIXCHARS);
190 		} else {
191 			DIGESTUpdate(&ctxA, plaintext, plaintext_len);
192 		}
193 	}
194 
195 	/* 12. */
196 	DIGESTFinal(A, &ctxA);
197 
198 	/* 13. - 15. */
199 	DIGESTInit(&ctxDP);
200 	for (i = 0; i < plaintext_len; i++)
201 		DIGESTUpdate(&ctxDP, plaintext, plaintext_len);
202 	DIGESTFinal(DP, &ctxDP);
203 
204 	/* 16. */
205 	Pp = P = alloca(plaintext_len);
206 	for (i = plaintext_len; i >= MIXCHARS; i -= MIXCHARS) {
207 		Pp = (char *)(memcpy(Pp, DP, MIXCHARS)) + MIXCHARS;
208 	}
209 	memcpy(Pp, DP, i);
210 
211 	/* 17. - 19. */
212 	DIGESTInit(&ctxDS);
213 	for (i = 0; i < 16 + (uint8_t)A[0]; i++)
214 		DIGESTUpdate(&ctxDS, salt, salt_len);
215 	DIGESTFinal(DS, &ctxDS);
216 
217 	/* 20. */
218 	Sp = S = alloca(salt_len);
219 	for (i = salt_len; i >= MIXCHARS; i -= MIXCHARS) {
220 		Sp = (char *)(memcpy(Sp, DS, MIXCHARS)) + MIXCHARS;
221 	}
222 	memcpy(Sp, DS, i);
223 
224 	/*  21. */
225 	for (i = 0; i < rounds; i++) {
226 		DIGESTInit(&ctxC);
227 
228 		if ((i & 1) != 0) {
229 			DIGESTUpdate(&ctxC, P, plaintext_len);
230 		} else {
231 			if (i == 0)
232 				DIGESTUpdate(&ctxC, A, MIXCHARS);
233 			else
234 				DIGESTUpdate(&ctxC, DP, MIXCHARS);
235 		}
236 
237 		if (i % 3 != 0) {
238 			DIGESTUpdate(&ctxC, S, salt_len);
239 		}
240 
241 		if (i % 7 != 0) {
242 			DIGESTUpdate(&ctxC, P, plaintext_len);
243 		}
244 
245 		if ((i & 1) != 0) {
246 			if (i == 0)
247 				DIGESTUpdate(&ctxC, A, MIXCHARS);
248 			else
249 				DIGESTUpdate(&ctxC, DP, MIXCHARS);
250 		} else {
251 			DIGESTUpdate(&ctxC, P, plaintext_len);
252 		}
253 		DIGESTFinal(DP, &ctxC);
254 	}
255 
256 	/* 22. Now make the output string */
257 	(void) strlcpy(ctbuffer, crypt_alg_magic, ctbufflen);
258 	if (custom_rounds) {
259 		(void) snprintf(ctbuffer, ctbufflen,
260 		    "%srounds=%zu$", ctbuffer, rounds);
261 	}
262 
263 	(void) strncat(ctbuffer, (const char *)salt, MAX_SALT_LEN);
264 	(void) strlcat(ctbuffer, "$", ctbufflen);
265 	p = ctbuffer + strlen(ctbuffer);
266 	ctbufflen -= strlen(ctbuffer);
267 
268 #ifdef CRYPT_SHA256
269 	b64_from_24bit(DP[ 0], DP[10], DP[20], 4);
270 	b64_from_24bit(DP[21], DP[ 1], DP[11], 4);
271 	b64_from_24bit(DP[12], DP[22], DP[ 2], 4);
272 	b64_from_24bit(DP[ 3], DP[13], DP[23], 4);
273 	b64_from_24bit(DP[24], DP[ 4], DP[14], 4);
274 	b64_from_24bit(DP[15], DP[25], DP[ 5], 4);
275 	b64_from_24bit(DP[ 6], DP[16], DP[26], 4);
276 	b64_from_24bit(DP[27], DP[ 7], DP[17], 4);
277 	b64_from_24bit(DP[18], DP[28], DP[ 8], 4);
278 	b64_from_24bit(DP[ 9], DP[19], DP[29], 4);
279 	b64_from_24bit(0, DP[31], DP[30], 3);
280 #elif CRYPT_SHA512
281 	b64_from_24bit(DP[ 0], DP[21], DP[42], 4);
282 	b64_from_24bit(DP[22], DP[43], DP[ 1], 4);
283 	b64_from_24bit(DP[44], DP[ 2], DP[23], 4);
284 	b64_from_24bit(DP[ 3], DP[24], DP[45], 4);
285 	b64_from_24bit(DP[25], DP[46], DP[ 4], 4);
286 	b64_from_24bit(DP[47], DP[ 5], DP[26], 4);
287 	b64_from_24bit(DP[ 6], DP[27], DP[48], 4);
288 	b64_from_24bit(DP[28], DP[49], DP[ 7], 4);
289 	b64_from_24bit(DP[50], DP[ 8], DP[29], 4);
290 	b64_from_24bit(DP[ 9], DP[30], DP[51], 4);
291 	b64_from_24bit(DP[31], DP[52], DP[10], 4);
292 	b64_from_24bit(DP[53], DP[11], DP[32], 4);
293 	b64_from_24bit(DP[12], DP[33], DP[54], 4);
294 	b64_from_24bit(DP[34], DP[55], DP[13], 4);
295 	b64_from_24bit(DP[56], DP[14], DP[35], 4);
296 	b64_from_24bit(DP[15], DP[36], DP[57], 4);
297 	b64_from_24bit(DP[37], DP[58], DP[16], 4);
298 	b64_from_24bit(DP[59], DP[17], DP[38], 4);
299 	b64_from_24bit(DP[18], DP[39], DP[60], 4);
300 	b64_from_24bit(DP[40], DP[61], DP[19], 4);
301 	b64_from_24bit(DP[62], DP[20], DP[41], 4);
302 	b64_from_24bit(0, 0, DP[63], 2);
303 #endif
304 	*p = '\0';
305 
306 	(void) memset(A, 0, sizeof (A));
307 	(void) memset(B, 0, sizeof (B));
308 	(void) memset(DP, 0, sizeof (DP));
309 	(void) memset(DS, 0, sizeof (DS));
310 
311 	return (ctbuffer);
312 }
313 
314 char *
315 crypt_gensalt_impl(char *gsbuffer,
316 	    size_t gsbufflen,
317 	    const char *oldsalt,
318 	    const struct passwd *userinfo,
319 	    const char **params)
320 {
321 	int fd;
322 	int err;
323 	ssize_t got;
324 	uint64_t rndval;
325 
326 	if ((fd = open("/dev/urandom", O_RDONLY)) == -1) {
327 		return (NULL);
328 	}
329 
330 	(void) strlcpy(gsbuffer, crypt_alg_magic, gsbufflen);
331 
332 	got = read(fd, &rndval, sizeof (rndval));
333 	if (got < sizeof (rndval)) {
334 		err = errno;
335 		(void) close(fd);
336 		errno = err;
337 		return (NULL);
338 	}
339 
340 	to64(&gsbuffer[strlen(crypt_alg_magic)], rndval, sizeof (rndval));
341 
342 	(void) close(fd);
343 
344 	return (gsbuffer);
345 }
346