1/*	$OpenBSD: bcrypt.c,v 1.29 2014/02/24 19:45:43 tedu Exp $	*/
2
3/*
4 * Copyright 1997 Niels Provos <provos@physnet.uni-hamburg.de>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. All advertising materials mentioning features or use of this software
16 *    must display the following acknowledgement:
17 *      This product includes software developed by Niels Provos.
18 * 4. The name of the author may not be used to endorse or promote products
19 *    derived from this software without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
26 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
30 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31 */
32
33#include <sys/cdefs.h>
34__FBSDID("$FreeBSD$");
35
36/* This password hashing algorithm was designed by David Mazieres
37 * <dm@lcs.mit.edu> and works as follows:
38 *
39 * 1. state := InitState ()
40 * 2. state := ExpandKey (state, salt, password)
41 * 3. REPEAT rounds:
42 *      state := ExpandKey (state, 0, password)
43 *	state := ExpandKey (state, 0, salt)
44 * 4. ctext := "OrpheanBeholderScryDoubt"
45 * 5. REPEAT 64:
46 * 	ctext := Encrypt_ECB (state, ctext);
47 * 6. RETURN Concatenate (salt, ctext);
48 *
49 */
50
51/*
52 * FreeBSD implementation by Paul Herman <pherman@frenchfries.net>
53 * and updated by Xin Li <delphij@FreeBSD.org>
54 */
55
56#include <stdio.h>
57#include <stdlib.h>
58#include <sys/types.h>
59#include <string.h>
60#include <pwd.h>
61#include "blowfish.h"
62#include "crypt.h"
63
64/* This implementation is adaptable to current computing power.
65 * You can have up to 2^31 rounds which should be enough for some
66 * time to come.
67 */
68
69#define BCRYPT_VERSION '2'
70#define BCRYPT_MAXSALT 16	/* Precomputation is just so nice */
71#define BCRYPT_BLOCKS 6		/* Ciphertext blocks */
72#define BCRYPT_MINLOGROUNDS 4	/* we have log2(rounds) in salt */
73
74
75static void encode_base64(u_int8_t *, u_int8_t *, u_int16_t);
76static void decode_base64(u_int8_t *, u_int16_t, const u_int8_t *);
77
78const static u_int8_t Base64Code[] =
79"./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
80
81const static u_int8_t index_64[128] = {
82	255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
83	255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
84	255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
85	255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
86	255, 255, 255, 255, 255, 255, 0, 1, 54, 55,
87	56, 57, 58, 59, 60, 61, 62, 63, 255, 255,
88	255, 255, 255, 255, 255, 2, 3, 4, 5, 6,
89	7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
90	17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27,
91	255, 255, 255, 255, 255, 255, 28, 29, 30,
92	31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
93	41, 42, 43, 44, 45, 46, 47, 48, 49, 50,
94	51, 52, 53, 255, 255, 255, 255, 255
95};
96#define CHAR64(c)  ( (c) > 127 ? 255 : index_64[(c)])
97
98static void
99decode_base64(u_int8_t *buffer, u_int16_t len, const u_int8_t *data)
100{
101	u_int8_t *bp = buffer;
102	const u_int8_t *p = data;
103	u_int8_t c1, c2, c3, c4;
104	while (bp < buffer + len) {
105		c1 = CHAR64(*p);
106		c2 = CHAR64(*(p + 1));
107
108		/* Invalid data */
109		if (c1 == 255 || c2 == 255)
110			break;
111
112		*bp++ = (c1 << 2) | ((c2 & 0x30) >> 4);
113		if (bp >= buffer + len)
114			break;
115
116		c3 = CHAR64(*(p + 2));
117		if (c3 == 255)
118			break;
119
120		*bp++ = ((c2 & 0x0f) << 4) | ((c3 & 0x3c) >> 2);
121		if (bp >= buffer + len)
122			break;
123
124		c4 = CHAR64(*(p + 3));
125		if (c4 == 255)
126			break;
127		*bp++ = ((c3 & 0x03) << 6) | c4;
128
129		p += 4;
130	}
131}
132
133/* We handle $Vers$log2(NumRounds)$salt+passwd$
134   i.e. $2$04$iwouldntknowwhattosayetKdJ6iFtacBqJdKe6aW7ou */
135
136int
137crypt_blowfish(const char *key, const char *salt, char *buffer)
138{
139	blf_ctx state;
140	u_int32_t rounds, i, k;
141	u_int16_t j;
142	size_t key_len;
143	u_int8_t salt_len, logr, minr;
144	u_int8_t ciphertext[4 * BCRYPT_BLOCKS] = "OrpheanBeholderScryDoubt";
145	u_int8_t csalt[BCRYPT_MAXSALT];
146	u_int32_t cdata[BCRYPT_BLOCKS];
147	char arounds[3];
148
149	/* Defaults */
150	minr = 'b';
151	logr = BCRYPT_MINLOGROUNDS;
152	rounds = 1U << logr;
153
154	if (*salt == '$') {
155		/* Discard "$" identifier */
156		salt++;
157
158		if (*salt > BCRYPT_VERSION)
159			return (-1);
160
161		/* Check for minor versions */
162		if (salt[1] != '$') {
163			 switch (salt[1]) {
164			 case 'a':	/* 'ab' should not yield the same as 'abab' */
165			 case 'b':	/* cap input length at 72 bytes */
166			 case 'y':	/* same as 'b', for compatibility
167					 * with openwall crypt_blowfish
168					 */
169				 minr = salt[1];
170				 salt++;
171				 break;
172			 default:
173				 return (-1);
174			 }
175		} else
176			 minr = 0;
177
178		/* Discard version + "$" identifier */
179		salt += 2;
180
181		if (salt[2] != '$')
182			/* Out of sync with passwd entry */
183			return (-1);
184
185		memcpy(arounds, salt, sizeof(arounds));
186		if (arounds[sizeof(arounds) - 1] != '$')
187			return (-1);
188		arounds[sizeof(arounds) - 1] = 0;
189		logr = strtonum(arounds, BCRYPT_MINLOGROUNDS, 31, NULL);
190		if (logr == 0)
191			return (-1);
192		/* Computer power doesn't increase linearly, 2^x should be fine */
193		rounds = 1U << logr;
194
195		/* Discard num rounds + "$" identifier */
196		salt += 3;
197	}
198
199	if (strlen(salt) * 3 / 4 < BCRYPT_MAXSALT)
200		return (-1);
201
202	/* We dont want the base64 salt but the raw data */
203	decode_base64(csalt, BCRYPT_MAXSALT, (const u_int8_t *) salt);
204	salt_len = BCRYPT_MAXSALT;
205	if (minr <= 'a')
206		key_len = (u_int8_t)(strlen(key) + (minr >= 'a' ? 1 : 0));
207	else {
208		/* strlen() returns a size_t, but the function calls
209		 * below result in implicit casts to a narrower integer
210		 * type, so cap key_len at the actual maximum supported
211		 * length here to avoid integer wraparound */
212		key_len = strlen(key);
213		if (key_len > 72)
214			key_len = 72;
215		key_len++; /* include the NUL */
216	}
217
218	/* Setting up S-Boxes and Subkeys */
219	Blowfish_initstate(&state);
220	Blowfish_expandstate(&state, csalt, salt_len,
221	    (const u_int8_t *) key, key_len);
222	for (k = 0; k < rounds; k++) {
223		Blowfish_expand0state(&state, (const u_int8_t *) key, key_len);
224		Blowfish_expand0state(&state, csalt, salt_len);
225	}
226
227	/* This can be precomputed later */
228	j = 0;
229	for (i = 0; i < BCRYPT_BLOCKS; i++)
230		cdata[i] = Blowfish_stream2word(ciphertext, 4 * BCRYPT_BLOCKS, &j);
231
232	/* Now do the encryption */
233	for (k = 0; k < 64; k++)
234		blf_enc(&state, cdata, BCRYPT_BLOCKS / 2);
235
236	for (i = 0; i < BCRYPT_BLOCKS; i++) {
237		ciphertext[4 * i + 3] = cdata[i] & 0xff;
238		cdata[i] = cdata[i] >> 8;
239		ciphertext[4 * i + 2] = cdata[i] & 0xff;
240		cdata[i] = cdata[i] >> 8;
241		ciphertext[4 * i + 1] = cdata[i] & 0xff;
242		cdata[i] = cdata[i] >> 8;
243		ciphertext[4 * i + 0] = cdata[i] & 0xff;
244	}
245
246
247	*buffer++ = '$';
248	*buffer++ = BCRYPT_VERSION;
249	if (minr)
250		*buffer++ = minr;
251	*buffer++ = '$';
252
253	snprintf(buffer, 4, "%2.2u$", logr);
254	buffer += 3;
255
256	encode_base64((u_int8_t *)buffer, csalt, BCRYPT_MAXSALT);
257	buffer += strlen(buffer);
258	encode_base64((u_int8_t *)buffer, ciphertext, 4 * BCRYPT_BLOCKS - 1);
259	memset(&state, 0, sizeof(state));
260	memset(ciphertext, 0, sizeof(ciphertext));
261	memset(csalt, 0, sizeof(csalt));
262	memset(cdata, 0, sizeof(cdata));
263	return (0);
264}
265
266static void
267encode_base64(u_int8_t *buffer, u_int8_t *data, u_int16_t len)
268{
269	u_int8_t *bp = buffer;
270	u_int8_t *p = data;
271	u_int8_t c1, c2;
272	while (p < data + len) {
273		c1 = *p++;
274		*bp++ = Base64Code[(c1 >> 2)];
275		c1 = (c1 & 0x03) << 4;
276		if (p >= data + len) {
277			*bp++ = Base64Code[c1];
278			break;
279		}
280		c2 = *p++;
281		c1 |= (c2 >> 4) & 0x0f;
282		*bp++ = Base64Code[c1];
283		c1 = (c2 & 0x0f) << 2;
284		if (p >= data + len) {
285			*bp++ = Base64Code[c1];
286			break;
287		}
288		c2 = *p++;
289		c1 |= (c2 >> 6) & 0x03;
290		*bp++ = Base64Code[c1];
291		*bp++ = Base64Code[c2 & 0x3f];
292	}
293	*bp = '\0';
294}
295#if 0
296void
297main()
298{
299	char    blubber[73];
300	char    salt[100];
301	char   *p;
302	salt[0] = '$';
303	salt[1] = BCRYPT_VERSION;
304	salt[2] = '$';
305
306	snprintf(salt + 3, 4, "%2.2u$", 5);
307
308	printf("24 bytes of salt: ");
309	fgets(salt + 6, sizeof(salt) - 6, stdin);
310	salt[99] = 0;
311	printf("72 bytes of password: ");
312	fpurge(stdin);
313	fgets(blubber, sizeof(blubber), stdin);
314	blubber[72] = 0;
315
316	p = crypt(blubber, salt);
317	printf("Passwd entry: %s\n\n", p);
318
319	p = bcrypt_gensalt(5);
320	printf("Generated salt: %s\n", p);
321	p = crypt(blubber, p);
322	printf("Passwd entry: %s\n", p);
323}
324#endif
325