1/*
2 * Copyright 1997 Niels Provos <provos@physnet.uni-hamburg.de>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *      This product includes software developed by Niels Provos.
16 * 4. The name of the author may not be used to endorse or promote products
17 *    derived from this software without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31#include <sys/cdefs.h>
32__FBSDID("$FreeBSD$");
33
34/* This password hashing algorithm was designed by David Mazieres
35 * <dm@lcs.mit.edu> and works as follows:
36 *
37 * 1. state := InitState ()
38 * 2. state := ExpandKey (state, salt, password) 3.
39 * REPEAT rounds:
40 *	state := ExpandKey (state, 0, salt)
41 *      state := ExpandKey(state, 0, password)
42 * 4. ctext := "OrpheanBeholderScryDoubt"
43 * 5. REPEAT 64:
44 * 	ctext := Encrypt_ECB (state, ctext);
45 * 6. RETURN Concatenate (salt, ctext);
46 *
47 */
48
49/*
50 * FreeBSD implementation by Paul Herman <pherman@frenchfries.net>
51 */
52
53#include <stdio.h>
54#include <stdlib.h>
55#include <sys/types.h>
56#include <string.h>
57#include <pwd.h>
58#include "blowfish.h"
59#include "crypt.h"
60
61/* This implementation is adaptable to current computing power.
62 * You can have up to 2^31 rounds which should be enough for some
63 * time to come.
64 */
65
66#define BCRYPT_VERSION '2'
67#define BCRYPT_MAXSALT 16	/* Precomputation is just so nice */
68#define BCRYPT_BLOCKS 6		/* Ciphertext blocks */
69#define BCRYPT_MINROUNDS 16	/* we have log2(rounds) in salt */
70
71static void encode_base64(u_int8_t *, u_int8_t *, u_int16_t);
72static void decode_base64(u_int8_t *, u_int16_t, const u_int8_t *);
73
74static char    encrypted[_PASSWORD_LEN];
75
76static const u_int8_t Base64Code[] =
77"./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
78
79static const u_int8_t index_64[128] =
80{
81	255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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, 0, 1, 54, 55,
86	56, 57, 58, 59, 60, 61, 62, 63, 255, 255,
87	255, 255, 255, 255, 255, 2, 3, 4, 5, 6,
88	7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
89	17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27,
90	255, 255, 255, 255, 255, 255, 28, 29, 30,
91	31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
92	41, 42, 43, 44, 45, 46, 47, 48, 49, 50,
93	51, 52, 53, 255, 255, 255, 255, 255
94};
95#define CHAR64(c)  ( (c) > 127 ? 255 : index_64[(c)])
96
97static void
98decode_base64(u_int8_t *buffer, u_int16_t len, const u_int8_t *data)
99{
100	u_int8_t *bp = buffer;
101	const u_int8_t *p = data;
102	u_int8_t c1, c2, c3, c4;
103	while (bp < buffer + len) {
104		c1 = CHAR64(*p);
105		c2 = CHAR64(*(p + 1));
106
107		/* Invalid data */
108		if (c1 == 255 || c2 == 255)
109			break;
110
111		*bp++ = (u_int8_t)((c1 << 2) | ((c2 & 0x30) >> 4));
112		if (bp >= buffer + len)
113			break;
114
115		c3 = CHAR64(*(p + 2));
116		if (c3 == 255)
117			break;
118
119		*bp++ = ((c2 & 0x0f) << 4) | ((c3 & 0x3c) >> 2);
120		if (bp >= buffer + len)
121			break;
122
123		c4 = CHAR64(*(p + 3));
124		if (c4 == 255)
125			break;
126		*bp++ = ((c3 & 0x03) << 6) | c4;
127
128		p += 4;
129	}
130}
131
132/* We handle $Vers$log2(NumRounds)$salt+passwd$
133   i.e. $2$04$iwouldntknowwhattosayetKdJ6iFtacBqJdKe6aW7ou */
134
135char   *
136crypt_blowfish(const char *key, const char *salt)
137{
138	blf_ctx state;
139	u_int32_t rounds, i, k;
140	u_int16_t j;
141	u_int8_t key_len, salt_len, logr, minr;
142	u_int8_t ciphertext[4 * BCRYPT_BLOCKS] = "OrpheanBeholderScryDoubt";
143	u_int8_t csalt[BCRYPT_MAXSALT];
144	u_int32_t cdata[BCRYPT_BLOCKS];
145	static const char     *magic = "$2a$04$";
146
147		/* Defaults */
148	minr = 'a';
149	logr = 4;
150	rounds = 1 << logr;
151
152        /* If it starts with the magic string, then skip that */
153	if(!strncmp(salt, magic, strlen(magic))) {
154		salt += strlen(magic);
155	}
156	else if (*salt == '$') {
157
158		/* Discard "$" identifier */
159		salt++;
160
161		if (*salt > BCRYPT_VERSION) {
162			/* How do I handle errors ? Return NULL */
163			return NULL;
164		}
165
166		/* Check for minor versions */
167		if (salt[1] != '$') {
168			 switch (salt[1]) {
169			 case 'a':
170				 /* 'ab' should not yield the same as 'abab' */
171				 minr = (u_int8_t)salt[1];
172				 salt++;
173				 break;
174			 default:
175				 return NULL;
176			 }
177		} else
178			 minr = 0;
179
180		/* Discard version + "$" identifier */
181		salt += 2;
182
183		if (salt[2] != '$')
184			/* Out of sync with passwd entry */
185			return NULL;
186
187		/* Computer power doesnt increase linear, 2^x should be fine */
188		logr = (u_int8_t)atoi(salt);
189		rounds = 1 << logr;
190		if (rounds < BCRYPT_MINROUNDS)
191			return NULL;
192
193		/* Discard num rounds + "$" identifier */
194		salt += 3;
195	}
196
197
198	/* We dont want the base64 salt but the raw data */
199	decode_base64(csalt, BCRYPT_MAXSALT, (const u_int8_t *)salt);
200	salt_len = BCRYPT_MAXSALT;
201	key_len = (u_int8_t)(strlen(key) + (minr >= 'a' ? 1 : 0));
202
203	/* Setting up S-Boxes and Subkeys */
204	Blowfish_initstate(&state);
205	Blowfish_expandstate(&state, csalt, salt_len,
206	    (const u_int8_t *) key, key_len);
207	for (k = 0; k < rounds; k++) {
208		Blowfish_expand0state(&state, (const u_int8_t *) key, key_len);
209		Blowfish_expand0state(&state, csalt, salt_len);
210	}
211
212	/* This can be precomputed later */
213	j = 0;
214	for (i = 0; i < BCRYPT_BLOCKS; i++)
215		cdata[i] = Blowfish_stream2word(ciphertext, 4 * BCRYPT_BLOCKS, &j);
216
217	/* Now do the encryption */
218	for (k = 0; k < 64; k++)
219		blf_enc(&state, cdata, BCRYPT_BLOCKS / 2);
220
221	for (i = 0; i < BCRYPT_BLOCKS; i++) {
222		ciphertext[4 * i + 3] = cdata[i] & 0xff;
223		cdata[i] = cdata[i] >> 8;
224		ciphertext[4 * i + 2] = cdata[i] & 0xff;
225		cdata[i] = cdata[i] >> 8;
226		ciphertext[4 * i + 1] = cdata[i] & 0xff;
227		cdata[i] = cdata[i] >> 8;
228		ciphertext[4 * i + 0] = cdata[i] & 0xff;
229	}
230
231
232	i = 0;
233	encrypted[i++] = '$';
234	encrypted[i++] = BCRYPT_VERSION;
235	if (minr)
236		encrypted[i++] = (int8_t)minr;
237	encrypted[i++] = '$';
238
239	snprintf(encrypted + i, 4, "%2.2u$", logr);
240
241	encode_base64((u_int8_t *) encrypted + i + 3, csalt, BCRYPT_MAXSALT);
242	encode_base64((u_int8_t *) encrypted + strlen(encrypted), ciphertext,
243	    4 * BCRYPT_BLOCKS - 1);
244	return encrypted;
245}
246
247static void
248encode_base64(u_int8_t *buffer, u_int8_t *data, u_int16_t len)
249{
250	u_int8_t *bp = buffer;
251	u_int8_t *p = data;
252	u_int8_t c1, c2;
253	while (p < data + len) {
254		c1 = *p++;
255		*bp++ = Base64Code[(c1 >> 2)];
256		c1 = (c1 & 0x03) << 4;
257		if (p >= data + len) {
258			*bp++ = Base64Code[c1];
259			break;
260		}
261		c2 = *p++;
262		c1 |= (c2 >> 4) & 0x0f;
263		*bp++ = Base64Code[c1];
264		c1 = (c2 & 0x0f) << 2;
265		if (p >= data + len) {
266			*bp++ = Base64Code[c1];
267			break;
268		}
269		c2 = *p++;
270		c1 |= (c2 >> 6) & 0x03;
271		*bp++ = Base64Code[c1];
272		*bp++ = Base64Code[c2 & 0x3f];
273	}
274	*bp = '\0';
275}
276
277#if 0
278void
279main()
280{
281	char    blubber[73];
282	char    salt[100];
283	char   *p;
284	salt[0] = '$';
285	salt[1] = BCRYPT_VERSION;
286	salt[2] = '$';
287
288	snprintf(salt + 3, 4, "%2.2u$", 5);
289
290	printf("24 bytes of salt: ");
291	fgets(salt + 6, 94, stdin);
292	salt[99] = 0;
293	printf("72 bytes of password: ");
294	fpurge(stdin);
295	fgets(blubber, 73, stdin);
296	blubber[72] = 0;
297
298	p = crypt(blubber, salt);
299	printf("Passwd entry: %s\n\n", p);
300
301	p = bcrypt_gensalt(5);
302	printf("Generated salt: %s\n", p);
303	p = crypt(blubber, p);
304	printf("Passwd entry: %s\n", p);
305}
306#endif
307