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 2009 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;
95
96
97static uchar_t b64t[] =		/* 0 ... 63 => ascii - 64 */
98	"./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
99
100#define	b64_from_24bit(B2, B1, B0, N) \
101{ \
102	uint_t w = ((B2) << 16) | ((B1) << 8) | (B0); \
103	int n = (N); \
104	while (--n >= 0 && ctbufflen > 0) { \
105		*p++ = b64t[w & 0x3f]; \
106		w >>= 6; \
107		ctbufflen--; \
108	} \
109}
110
111static void
112to64(char *s, uint64_t v, int n)
113{
114	while (--n >= 0) {
115		*s++ = b64t[v & 0x3f];
116		v >>= 6;
117	}
118}
119
120#define	ROUNDS		"rounds="
121#define	ROUNDSLEN	(sizeof (ROUNDS) - 1)
122
123/*
124 * get the integer value after rounds= where ever it occurs in the string.
125 * if the last char after the int is a , or $ that is fine anything else is an
126 * error.
127 */
128static uint32_t
129getrounds(const char *s)
130{
131	char *r, *p, *e;
132	long val;
133
134	if (s == NULL)
135		return (0);
136
137	if ((r = strstr(s, ROUNDS)) == NULL) {
138		return (0);
139	}
140
141	if (strncmp(r, ROUNDS, ROUNDSLEN) != 0) {
142		return (0);
143	}
144
145	p = r + ROUNDSLEN;
146	errno = 0;
147	val = strtol(p, &e, 10);
148	/*
149	 * An error occurred or there is non-numeric stuff at the end
150	 * which isn't one of the crypt(3c) special chars ',' or '$'
151	 */
152	if (errno != 0 || val < 0 ||
153	    !(*e == '\0' || *e == ',' || *e == '$')) {
154		return (0);
155	}
156
157	return ((uint32_t)val);
158}
159
160
161/* ARGSUSED4 */
162char *
163crypt_genhash_impl(char *ctbuffer,
164	    size_t ctbufflen,
165	    const char *plaintext,
166	    const char *switchsalt,
167	    const char **params)
168{
169	int salt_len, plaintext_len, i;
170	char *salt;
171	uchar_t A[DIGEST_LEN];
172	uchar_t B[DIGEST_LEN];
173	uchar_t DP[DIGEST_LEN];
174	uchar_t DS[DIGEST_LEN];
175	DIGEST_CTX ctxA, ctxB, ctxC, ctxDP, ctxDS;
176	int rounds = ROUNDS_DEFAULT;
177	int srounds = 0;
178	boolean_t custom_rounds = B_FALSE;
179	char *p;
180	char *P, *Pp;
181	char *S, *Sp;
182
183	/* Refine the salt */
184	salt = (char *)switchsalt;
185
186	/* skip our magic string */
187	if (strncmp((char *)salt, crypt_alg_magic, crypt_alg_magic_len) == 0) {
188		salt += crypt_alg_magic_len + 1;
189	}
190
191	srounds = getrounds(salt);
192	if (srounds != 0) {
193		rounds = MAX(ROUNDS_MIN, MIN(srounds, ROUNDS_MAX));
194		custom_rounds = B_TRUE;
195		p = strchr(salt, '$');
196		if (p != NULL)
197			salt = p + 1;
198	}
199
200	salt_len = MIN(strcspn(salt, "$"), MAX_SALT_LEN);
201	plaintext_len = strlen(plaintext);
202
203	/* 1. */
204	DIGESTInit(&ctxA);
205
206	/* 2. The password first, since that is what is most unknown */
207	DIGESTUpdate(&ctxA, plaintext, plaintext_len);
208
209	/* 3. Then the raw salt */
210	DIGESTUpdate(&ctxA, salt, salt_len);
211
212	/* 4. - 8. */
213	DIGESTInit(&ctxB);
214	DIGESTUpdate(&ctxB, plaintext, plaintext_len);
215	DIGESTUpdate(&ctxB, salt, salt_len);
216	DIGESTUpdate(&ctxB, plaintext, plaintext_len);
217	DIGESTFinal(B, &ctxB);
218
219	/* 9. - 10. */
220	for (i = plaintext_len; i > MIXCHARS; i -= MIXCHARS)
221		DIGESTUpdate(&ctxA, B, MIXCHARS);
222	DIGESTUpdate(&ctxA, B, i);
223
224	/* 11. */
225	for (i = plaintext_len; i > 0; i >>= 1) {
226		if ((i & 1) != 0) {
227			DIGESTUpdate(&ctxA, B, MIXCHARS);
228		} else {
229			DIGESTUpdate(&ctxA, plaintext, plaintext_len);
230		}
231	}
232
233	/* 12. */
234	DIGESTFinal(A, &ctxA);
235
236	/* 13. - 15. */
237	DIGESTInit(&ctxDP);
238	for (i = 0; i < plaintext_len; i++)
239		DIGESTUpdate(&ctxDP, plaintext, plaintext_len);
240	DIGESTFinal(DP, &ctxDP);
241
242	/* 16. */
243	Pp = P = alloca(plaintext_len);
244	for (i = plaintext_len; i >= MIXCHARS; i -= MIXCHARS) {
245		Pp = (char *)(memcpy(Pp, DP, MIXCHARS)) + MIXCHARS;
246	}
247	(void) memcpy(Pp, DP, i);
248
249	/* 17. - 19. */
250	DIGESTInit(&ctxDS);
251	for (i = 0; i < 16 + (uint8_t)A[0]; i++)
252		DIGESTUpdate(&ctxDS, salt, salt_len);
253	DIGESTFinal(DS, &ctxDS);
254
255	/* 20. */
256	Sp = S = alloca(salt_len);
257	for (i = salt_len; i >= MIXCHARS; i -= MIXCHARS) {
258		Sp = (char *)(memcpy(Sp, DS, MIXCHARS)) + MIXCHARS;
259	}
260	(void) memcpy(Sp, DS, i);
261
262	/*  21. */
263	for (i = 0; i < rounds; i++) {
264		DIGESTInit(&ctxC);
265
266		if ((i & 1) != 0) {
267			DIGESTUpdate(&ctxC, P, plaintext_len);
268		} else {
269			if (i == 0)
270				DIGESTUpdate(&ctxC, A, MIXCHARS);
271			else
272				DIGESTUpdate(&ctxC, DP, MIXCHARS);
273		}
274
275		if (i % 3 != 0) {
276			DIGESTUpdate(&ctxC, S, salt_len);
277		}
278
279		if (i % 7 != 0) {
280			DIGESTUpdate(&ctxC, P, plaintext_len);
281		}
282
283		if ((i & 1) != 0) {
284			if (i == 0)
285				DIGESTUpdate(&ctxC, A, MIXCHARS);
286			else
287				DIGESTUpdate(&ctxC, DP, MIXCHARS);
288		} else {
289			DIGESTUpdate(&ctxC, P, plaintext_len);
290		}
291		DIGESTFinal(DP, &ctxC);
292	}
293
294	/* 22. Now make the output string */
295	if (custom_rounds) {
296		(void) snprintf(ctbuffer, ctbufflen,
297		    "%s$rounds=%zu$", crypt_alg_magic, rounds);
298	} else {
299		(void) snprintf(ctbuffer, ctbufflen,
300		    "%s$", crypt_alg_magic);
301	}
302	(void) strncat(ctbuffer, (const char *)salt, salt_len);
303	(void) strlcat(ctbuffer, "$", ctbufflen);
304
305	p = ctbuffer + strlen(ctbuffer);
306	ctbufflen -= strlen(ctbuffer);
307
308#ifdef CRYPT_SHA256
309	b64_from_24bit(DP[ 0], DP[10], DP[20], 4);
310	b64_from_24bit(DP[21], DP[ 1], DP[11], 4);
311	b64_from_24bit(DP[12], DP[22], DP[ 2], 4);
312	b64_from_24bit(DP[ 3], DP[13], DP[23], 4);
313	b64_from_24bit(DP[24], DP[ 4], DP[14], 4);
314	b64_from_24bit(DP[15], DP[25], DP[ 5], 4);
315	b64_from_24bit(DP[ 6], DP[16], DP[26], 4);
316	b64_from_24bit(DP[27], DP[ 7], DP[17], 4);
317	b64_from_24bit(DP[18], DP[28], DP[ 8], 4);
318	b64_from_24bit(DP[ 9], DP[19], DP[29], 4);
319	b64_from_24bit(0, DP[31], DP[30], 3);
320#elif CRYPT_SHA512
321	b64_from_24bit(DP[ 0], DP[21], DP[42], 4);
322	b64_from_24bit(DP[22], DP[43], DP[ 1], 4);
323	b64_from_24bit(DP[44], DP[ 2], DP[23], 4);
324	b64_from_24bit(DP[ 3], DP[24], DP[45], 4);
325	b64_from_24bit(DP[25], DP[46], DP[ 4], 4);
326	b64_from_24bit(DP[47], DP[ 5], DP[26], 4);
327	b64_from_24bit(DP[ 6], DP[27], DP[48], 4);
328	b64_from_24bit(DP[28], DP[49], DP[ 7], 4);
329	b64_from_24bit(DP[50], DP[ 8], DP[29], 4);
330	b64_from_24bit(DP[ 9], DP[30], DP[51], 4);
331	b64_from_24bit(DP[31], DP[52], DP[10], 4);
332	b64_from_24bit(DP[53], DP[11], DP[32], 4);
333	b64_from_24bit(DP[12], DP[33], DP[54], 4);
334	b64_from_24bit(DP[34], DP[55], DP[13], 4);
335	b64_from_24bit(DP[56], DP[14], DP[35], 4);
336	b64_from_24bit(DP[15], DP[36], DP[57], 4);
337	b64_from_24bit(DP[37], DP[58], DP[16], 4);
338	b64_from_24bit(DP[59], DP[17], DP[38], 4);
339	b64_from_24bit(DP[18], DP[39], DP[60], 4);
340	b64_from_24bit(DP[40], DP[61], DP[19], 4);
341	b64_from_24bit(DP[62], DP[20], DP[41], 4);
342	b64_from_24bit(0, 0, DP[63], 2);
343#endif
344	*p = '\0';
345
346	(void) memset(A, 0, sizeof (A));
347	(void) memset(B, 0, sizeof (B));
348	(void) memset(DP, 0, sizeof (DP));
349	(void) memset(DS, 0, sizeof (DS));
350
351	return (ctbuffer);
352}
353
354
355/* ARGSUSED3 */
356char *
357crypt_gensalt_impl(char *gsbuffer,
358	    size_t gsbufflen,
359	    const char *oldsalt,
360	    const struct passwd *userinfo,
361	    const char **params)
362{
363	int fd;
364	int err;
365	ssize_t got;
366	uint64_t rndval;
367	uint32_t confrounds = 0;
368	uint32_t saltrounds;
369	char rndstr[sizeof (rndval) + 1];
370	int i;
371
372	for (i = 0; params != NULL && params[i] != NULL; i++) {
373		if (strncmp(params[i], ROUNDS, ROUNDSLEN) == 0) {
374			confrounds = getrounds(params[i]);
375		} else {
376			errno = EINVAL;
377			return (NULL);
378		}
379	}
380
381	/*
382	 * If the config file has a higher value for rounds= than what
383	 * was in the old salt use that, otherwise keep what was in the
384	 * old salt.
385	 */
386	saltrounds = getrounds(oldsalt);
387	if (confrounds > saltrounds) {
388		saltrounds = confrounds;
389	}
390
391	if ((fd = open("/dev/urandom", O_RDONLY)) == -1) {
392		return (NULL);
393	}
394
395	got = read(fd, &rndval, sizeof (rndval));
396	if (got < sizeof (rndval)) {
397		err = errno;
398		(void) close(fd);
399		errno = err;
400		return (NULL);
401	}
402	(void) close(fd);
403
404	to64((char *)&rndstr, rndval, sizeof (rndval));
405	rndstr[sizeof (rndstr) - 1] = 0;
406
407	if (saltrounds > 0) {
408		if (snprintf(gsbuffer, gsbufflen,
409		    "%s$rounds=%d$",
410		    crypt_alg_magic, saltrounds) >= gsbufflen)
411			goto fail;
412	} else {
413		if (snprintf(gsbuffer, gsbufflen,
414		    "%s$", crypt_alg_magic) >= gsbufflen)
415			goto fail;
416	}
417	if (strlcat(gsbuffer, rndstr, gsbufflen) >= gsbufflen)
418		goto fail;
419	if (strlcat(gsbuffer, "$", gsbufflen) >= gsbufflen)
420		goto fail;
421
422	return (gsbuffer);
423
424fail:
425	(void) memset(gsbuffer, 0, gsbufflen);
426	return (gsbuffer);
427}
428