crypt_sha.c revision 7314:2ded6fdd4e05 
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/*
27 * Portions of this code from crypt_bsdmd5.so (bsdmd5.c) :
28 * ----------------------------------------------------------------------------
29 * "THE BEER-WARE LICENSE" (Revision 42):
30 * <phk@login.dknet.dk> wrote this file.  As long as you retain this notice you
31 * can do whatever you want with this stuff. If we meet some day, and you think
32 * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
33 * ----------------------------------------------------------------------------
34 *
35 * $FreeBSD: crypt.c,v 1.5 1996/10/14 08:34:02 phk Exp $
36 *
37 */
38
39/*
40 * Implements the specification from:
41 *
42 * From http://people.redhat.com/drepper/SHA-crypt.txt
43 *
44 * Portions of the code taken from inspired by or verified against the
45 * source in the above document which is licensed as:
46 *
47 * "Released into the Public Domain by Ulrich Drepper <drepper@redhat.com>."
48 */
49
50
51#include <sys/types.h>
52#include <sys/stat.h>
53#include <sys/sysmacros.h>
54#include <fcntl.h>
55#include <unistd.h>
56#include <string.h>
57#include <stdio.h>
58#include <errno.h>
59#include <stdlib.h>
60#include <alloca.h>
61
62#include <sha2.h>
63#include <crypt.h>
64
65#define	MAX_SALT_LEN	16
66#define	ROUNDS_DEFAULT	5000
67#define	ROUNDS_MIN	1000
68#define	ROUNDS_MAX	999999999
69
70#ifdef CRYPT_SHA256
71
72#define	DIGEST_CTX	SHA256_CTX
73#define	DIGESTInit	SHA256Init
74#define	DIGESTUpdate	SHA256Update
75#define	DIGESTFinal	SHA256Final
76#define	DIGEST_LEN	SHA256_DIGEST_LENGTH
77#define	MIXCHARS	32
78static const char crypt_alg_magic[] = "$5$";
79
80#elif CRYPT_SHA512
81
82#define	DIGEST_CTX	SHA512_CTX
83#define	DIGESTInit	SHA512Init
84#define	DIGESTUpdate	SHA512Update
85#define	DIGESTFinal	SHA512Final
86#define	DIGEST_LEN	SHA512_DIGEST_LENGTH
87#define	MIXCHARS	64
88static const char crypt_alg_magic[] = "$6$";
89
90#else
91#error	"One of CRYPT_256 or CRYPT_512 must be defined"
92#endif
93
94static const int crypt_alg_magic_len = sizeof (crypt_alg_magic) - 1;
95static const char rounds_prefix[] = "rounds=";
96
97
98static uchar_t b64t[] =		/* 0 ... 63 => ascii - 64 */
99	"./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
100
101#define	b64_from_24bit(B2, B1, B0, N) \
102{ \
103	uint_t w = ((B2) << 16) | ((B1) << 8) | (B0); \
104	int n = (N); \
105	while (--n >= 0 && ctbufflen > 0) { \
106		*p++ = b64t[w & 0x3f]; \
107		w >>= 6; \
108		ctbufflen--; \
109	} \
110}
111
112static void
113to64(char *s, uint64_t v, int n)
114{
115	while (--n >= 0) {
116		*s++ = b64t[v&0x3f];
117		v >>= 6;
118	}
119}
120
121char *
122crypt_genhash_impl(char *ctbuffer,
123	    size_t ctbufflen,
124	    const char *plaintext,
125	    const char *switchsalt,
126	    const char **params)
127{
128	int salt_len, plaintext_len, i;
129	char *salt;
130	uchar_t A[DIGEST_LEN];
131	uchar_t B[DIGEST_LEN];
132	uchar_t DP[DIGEST_LEN];
133	uchar_t DS[DIGEST_LEN];
134	DIGEST_CTX ctxA, ctxB, ctxC, ctxDP, ctxDS;
135	int rounds = ROUNDS_DEFAULT;
136	boolean_t custom_rounds = B_FALSE;
137	char *p;
138	char *P, *Pp;
139	char *S, *Sp;
140
141	/* Refine the salt */
142	salt = (char *)switchsalt;
143
144	/* skip our magic string */
145	if (strncmp((char *)salt, crypt_alg_magic, crypt_alg_magic_len) == 0) {
146		salt += crypt_alg_magic_len;
147	}
148
149	if (strncmp(salt, rounds_prefix, sizeof (rounds_prefix) - 1) == 0) {
150		char *num = salt + sizeof (rounds_prefix) - 1;
151		char *endp;
152		ulong_t srounds = strtoul(num, &endp, 10);
153		if (*endp == '$') {
154			salt = endp + 1;
155			rounds = MAX(ROUNDS_MIN, MIN(srounds, ROUNDS_MAX));
156			custom_rounds = B_TRUE;
157		}
158	}
159
160	salt_len = MIN(strcspn(salt, "$"), MAX_SALT_LEN);
161	plaintext_len = strlen(plaintext);
162
163	/* 1. */
164	DIGESTInit(&ctxA);
165
166	/* 2. The password first, since that is what is most unknown */
167	DIGESTUpdate(&ctxA, plaintext, plaintext_len);
168
169	/* 3. Then the raw salt */
170	DIGESTUpdate(&ctxA, salt, salt_len);
171
172	/* 4. - 8. */
173	DIGESTInit(&ctxB);
174	DIGESTUpdate(&ctxB, plaintext, plaintext_len);
175	DIGESTUpdate(&ctxB, salt, salt_len);
176	DIGESTUpdate(&ctxB, plaintext, plaintext_len);
177	DIGESTFinal(B, &ctxB);
178
179	/* 9. - 10. */
180	for (i = plaintext_len; i > MIXCHARS; i -= MIXCHARS)
181		DIGESTUpdate(&ctxA, B, MIXCHARS);
182	DIGESTUpdate(&ctxA, B, i);
183
184	/* 11. */
185	for (i = plaintext_len; i > 0; i >>= 1) {
186		if ((i & 1) != 0) {
187			DIGESTUpdate(&ctxA, B, MIXCHARS);
188		} else {
189			DIGESTUpdate(&ctxA, plaintext, plaintext_len);
190		}
191	}
192
193	/* 12. */
194	DIGESTFinal(A, &ctxA);
195
196	/* 13. - 15. */
197	DIGESTInit(&ctxDP);
198	for (i = 0; i < plaintext_len; i++)
199		DIGESTUpdate(&ctxDP, plaintext, plaintext_len);
200	DIGESTFinal(DP, &ctxDP);
201
202	/* 16. */
203	Pp = P = alloca(plaintext_len);
204	for (i = plaintext_len; i >= MIXCHARS; i -= MIXCHARS) {
205		Pp = (char *)(memcpy(Pp, DP, MIXCHARS)) + MIXCHARS;
206	}
207	memcpy(Pp, DP, i);
208
209	/* 17. - 19. */
210	DIGESTInit(&ctxDS);
211	for (i = 0; i < 16 + (uint8_t)A[0]; i++)
212		DIGESTUpdate(&ctxDS, salt, salt_len);
213	DIGESTFinal(DS, &ctxDS);
214
215	/* 20. */
216	Sp = S = alloca(salt_len);
217	for (i = salt_len; i >= MIXCHARS; i -= MIXCHARS) {
218		Sp = (char *)(memcpy(Sp, DS, MIXCHARS)) + MIXCHARS;
219	}
220	memcpy(Sp, DS, i);
221
222	/*  21. */
223	for (i = 0; i < rounds; i++) {
224		DIGESTInit(&ctxC);
225
226		if ((i & 1) != 0) {
227			DIGESTUpdate(&ctxC, P, plaintext_len);
228		} else {
229			if (i == 0)
230				DIGESTUpdate(&ctxC, A, MIXCHARS);
231			else
232				DIGESTUpdate(&ctxC, DP, MIXCHARS);
233		}
234
235		if (i % 3 != 0) {
236			DIGESTUpdate(&ctxC, S, salt_len);
237		}
238
239		if (i % 7 != 0) {
240			DIGESTUpdate(&ctxC, P, plaintext_len);
241		}
242
243		if ((i & 1) != 0) {
244			if (i == 0)
245				DIGESTUpdate(&ctxC, A, MIXCHARS);
246			else
247				DIGESTUpdate(&ctxC, DP, MIXCHARS);
248		} else {
249			DIGESTUpdate(&ctxC, P, plaintext_len);
250		}
251		DIGESTFinal(DP, &ctxC);
252	}
253
254	/* 22. Now make the output string */
255	(void) strlcpy(ctbuffer, crypt_alg_magic, ctbufflen);
256	if (custom_rounds) {
257		(void) snprintf(ctbuffer, ctbufflen,
258		    "%srounds=%zu$", ctbuffer, rounds);
259	}
260
261	(void) strncat(ctbuffer, (const char *)salt, salt_len);
262	(void) strlcat(ctbuffer, "$", ctbufflen);
263	p = ctbuffer + strlen(ctbuffer);
264	ctbufflen -= strlen(ctbuffer);
265
266#ifdef CRYPT_SHA256
267	b64_from_24bit(DP[ 0], DP[10], DP[20], 4);
268	b64_from_24bit(DP[21], DP[ 1], DP[11], 4);
269	b64_from_24bit(DP[12], DP[22], DP[ 2], 4);
270	b64_from_24bit(DP[ 3], DP[13], DP[23], 4);
271	b64_from_24bit(DP[24], DP[ 4], DP[14], 4);
272	b64_from_24bit(DP[15], DP[25], DP[ 5], 4);
273	b64_from_24bit(DP[ 6], DP[16], DP[26], 4);
274	b64_from_24bit(DP[27], DP[ 7], DP[17], 4);
275	b64_from_24bit(DP[18], DP[28], DP[ 8], 4);
276	b64_from_24bit(DP[ 9], DP[19], DP[29], 4);
277	b64_from_24bit(0, DP[31], DP[30], 3);
278#elif CRYPT_SHA512
279	b64_from_24bit(DP[ 0], DP[21], DP[42], 4);
280	b64_from_24bit(DP[22], DP[43], DP[ 1], 4);
281	b64_from_24bit(DP[44], DP[ 2], DP[23], 4);
282	b64_from_24bit(DP[ 3], DP[24], DP[45], 4);
283	b64_from_24bit(DP[25], DP[46], DP[ 4], 4);
284	b64_from_24bit(DP[47], DP[ 5], DP[26], 4);
285	b64_from_24bit(DP[ 6], DP[27], DP[48], 4);
286	b64_from_24bit(DP[28], DP[49], DP[ 7], 4);
287	b64_from_24bit(DP[50], DP[ 8], DP[29], 4);
288	b64_from_24bit(DP[ 9], DP[30], DP[51], 4);
289	b64_from_24bit(DP[31], DP[52], DP[10], 4);
290	b64_from_24bit(DP[53], DP[11], DP[32], 4);
291	b64_from_24bit(DP[12], DP[33], DP[54], 4);
292	b64_from_24bit(DP[34], DP[55], DP[13], 4);
293	b64_from_24bit(DP[56], DP[14], DP[35], 4);
294	b64_from_24bit(DP[15], DP[36], DP[57], 4);
295	b64_from_24bit(DP[37], DP[58], DP[16], 4);
296	b64_from_24bit(DP[59], DP[17], DP[38], 4);
297	b64_from_24bit(DP[18], DP[39], DP[60], 4);
298	b64_from_24bit(DP[40], DP[61], DP[19], 4);
299	b64_from_24bit(DP[62], DP[20], DP[41], 4);
300	b64_from_24bit(0, 0, DP[63], 2);
301#endif
302	*p = '\0';
303
304	(void) memset(A, 0, sizeof (A));
305	(void) memset(B, 0, sizeof (B));
306	(void) memset(DP, 0, sizeof (DP));
307	(void) memset(DS, 0, sizeof (DS));
308
309	return (ctbuffer);
310}
311
312char *
313crypt_gensalt_impl(char *gsbuffer,
314	    size_t gsbufflen,
315	    const char *oldsalt,
316	    const struct passwd *userinfo,
317	    const char **params)
318{
319	int fd;
320	int err;
321	ssize_t got;
322	uint64_t rndval;
323
324	if ((fd = open("/dev/urandom", O_RDONLY)) == -1) {
325		return (NULL);
326	}
327
328	(void) strlcpy(gsbuffer, crypt_alg_magic, gsbufflen);
329
330	got = read(fd, &rndval, sizeof (rndval));
331	if (got < sizeof (rndval)) {
332		err = errno;
333		(void) close(fd);
334		errno = err;
335		return (NULL);
336	}
337
338	to64(&gsbuffer[strlen(crypt_alg_magic)], rndval, sizeof (rndval));
339
340	(void) close(fd);
341
342	return (gsbuffer);
343}
344