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: stable/9/secure/lib/libcrypt/crypt-blowfish.c 266818 2014-05-28 19:05:46Z delphij $");
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
75 static void encode_base64(u_int8_t *, u_int8_t *, u_int16_t);
76 static void decode_base64(u_int8_t *, u_int16_t, const u_int8_t *);
77
78 static char encrypted[_PASSWORD_LEN];
79 static char error[] = ":";
80
81 const static u_int8_t Base64Code[] =
82 "./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
83
84 const static u_int8_t index_64[128] = {
85 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
86 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
87 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
88 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
89 255, 255, 255, 255, 255, 255, 0, 1, 54, 55,
90 56, 57, 58, 59, 60, 61, 62, 63, 255, 255,
91 255, 255, 255, 255, 255, 2, 3, 4, 5, 6,
92 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
93 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27,
94 255, 255, 255, 255, 255, 255, 28, 29, 30,
95 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
96 41, 42, 43, 44, 45, 46, 47, 48, 49, 50,
97 51, 52, 53, 255, 255, 255, 255, 255
98 };
99 #define CHAR64(c) ( (c) > 127 ? 255 : index_64[(c)])
100
101 static void
decode_base64(u_int8_t * buffer,u_int16_t len,const u_int8_t * data)102 decode_base64(u_int8_t *buffer, u_int16_t len, const u_int8_t *data)
103 {
104 u_int8_t *bp = buffer;
105 const u_int8_t *p = data;
106 u_int8_t c1, c2, c3, c4;
107 while (bp < buffer + len) {
108 c1 = CHAR64(*p);
109 c2 = CHAR64(*(p + 1));
110
111 /* Invalid data */
112 if (c1 == 255 || c2 == 255)
113 break;
114
115 *bp++ = (c1 << 2) | ((c2 & 0x30) >> 4);
116 if (bp >= buffer + len)
117 break;
118
119 c3 = CHAR64(*(p + 2));
120 if (c3 == 255)
121 break;
122
123 *bp++ = ((c2 & 0x0f) << 4) | ((c3 & 0x3c) >> 2);
124 if (bp >= buffer + len)
125 break;
126
127 c4 = CHAR64(*(p + 3));
128 if (c4 == 255)
129 break;
130 *bp++ = ((c3 & 0x03) << 6) | c4;
131
132 p += 4;
133 }
134 }
135
136 /* We handle $Vers$log2(NumRounds)$salt+passwd$
137 i.e. $2$04$iwouldntknowwhattosayetKdJ6iFtacBqJdKe6aW7ou */
138
139 char *
crypt_blowfish(const char * key,const char * salt)140 crypt_blowfish(const char *key, const char *salt)
141 {
142 blf_ctx state;
143 u_int32_t rounds, i, k;
144 u_int16_t j;
145 size_t key_len;
146 u_int8_t salt_len, logr, minr;
147 u_int8_t ciphertext[4 * BCRYPT_BLOCKS] = "OrpheanBeholderScryDoubt";
148 u_int8_t csalt[BCRYPT_MAXSALT];
149 u_int32_t cdata[BCRYPT_BLOCKS];
150 char arounds[3];
151
152 /* Defaults */
153 minr = 'b';
154 logr = BCRYPT_MINLOGROUNDS;
155 rounds = 1U << logr;
156
157 if (*salt == '$') {
158 /* Discard "$" identifier */
159 salt++;
160
161 if (*salt > BCRYPT_VERSION) {
162 /* How do I handle errors ? Return ':' */
163 return error;
164 }
165
166 /* Check for minor versions */
167 if (salt[1] != '$') {
168 switch (salt[1]) {
169 case 'a': /* 'ab' should not yield the same as 'abab' */
170 case 'b': /* cap input length at 72 bytes */
171 minr = salt[1];
172 salt++;
173 break;
174 default:
175 return error;
176 }
177 } else
178 minr = 0;
179
180 /* Discard version + "$" identifier */
181 salt += 2;
182
183 if (salt[2] != '$')
184 /* Out of sync with passwd entry */
185 return error;
186
187 memcpy(arounds, salt, sizeof(arounds));
188 if (arounds[sizeof(arounds) - 1] != '$')
189 return error;
190 arounds[sizeof(arounds) - 1] = 0;
191 logr = strtonum(arounds, BCRYPT_MINLOGROUNDS, 31, NULL);
192 if (logr == 0)
193 return NULL;
194 /* Computer power doesn't increase linearly, 2^x should be fine */
195 rounds = 1U << logr;
196
197 /* Discard num rounds + "$" identifier */
198 salt += 3;
199 }
200
201 if (strlen(salt) * 3 / 4 < BCRYPT_MAXSALT)
202 return NULL;
203
204 /* We dont want the base64 salt but the raw data */
205 decode_base64(csalt, BCRYPT_MAXSALT, (const u_int8_t *) salt);
206 salt_len = BCRYPT_MAXSALT;
207 if (minr <= 'a')
208 key_len = (u_int8_t)(strlen(key) + (minr >= 'a' ? 1 : 0));
209 else {
210 /* strlen() returns a size_t, but the function calls
211 * below result in implicit casts to a narrower integer
212 * type, so cap key_len at the actual maximum supported
213 * length here to avoid integer wraparound */
214 key_len = strlen(key);
215 if (key_len > 72)
216 key_len = 72;
217 key_len++; /* include the NUL */
218 }
219
220 /* Setting up S-Boxes and Subkeys */
221 Blowfish_initstate(&state);
222 Blowfish_expandstate(&state, csalt, salt_len,
223 (const u_int8_t *) key, key_len);
224 for (k = 0; k < rounds; k++) {
225 Blowfish_expand0state(&state, (const u_int8_t *) key, key_len);
226 Blowfish_expand0state(&state, csalt, salt_len);
227 }
228
229 /* This can be precomputed later */
230 j = 0;
231 for (i = 0; i < BCRYPT_BLOCKS; i++)
232 cdata[i] = Blowfish_stream2word(ciphertext, 4 * BCRYPT_BLOCKS, &j);
233
234 /* Now do the encryption */
235 for (k = 0; k < 64; k++)
236 blf_enc(&state, cdata, BCRYPT_BLOCKS / 2);
237
238 for (i = 0; i < BCRYPT_BLOCKS; i++) {
239 ciphertext[4 * i + 3] = cdata[i] & 0xff;
240 cdata[i] = cdata[i] >> 8;
241 ciphertext[4 * i + 2] = cdata[i] & 0xff;
242 cdata[i] = cdata[i] >> 8;
243 ciphertext[4 * i + 1] = cdata[i] & 0xff;
244 cdata[i] = cdata[i] >> 8;
245 ciphertext[4 * i + 0] = cdata[i] & 0xff;
246 }
247
248
249 i = 0;
250 encrypted[i++] = '$';
251 encrypted[i++] = BCRYPT_VERSION;
252 if (minr)
253 encrypted[i++] = minr;
254 encrypted[i++] = '$';
255
256 snprintf(encrypted + i, 4, "%2.2u$", logr);
257
258 encode_base64((u_int8_t *) encrypted + i + 3, csalt, BCRYPT_MAXSALT);
259 encode_base64((u_int8_t *) encrypted + strlen(encrypted), ciphertext,
260 4 * BCRYPT_BLOCKS - 1);
261 memset(&state, 0, sizeof(state));
262 memset(ciphertext, 0, sizeof(ciphertext));
263 memset(csalt, 0, sizeof(csalt));
264 memset(cdata, 0, sizeof(cdata));
265 return encrypted;
266 }
267
268 static void
encode_base64(u_int8_t * buffer,u_int8_t * data,u_int16_t len)269 encode_base64(u_int8_t *buffer, u_int8_t *data, u_int16_t len)
270 {
271 u_int8_t *bp = buffer;
272 u_int8_t *p = data;
273 u_int8_t c1, c2;
274 while (p < data + len) {
275 c1 = *p++;
276 *bp++ = Base64Code[(c1 >> 2)];
277 c1 = (c1 & 0x03) << 4;
278 if (p >= data + len) {
279 *bp++ = Base64Code[c1];
280 break;
281 }
282 c2 = *p++;
283 c1 |= (c2 >> 4) & 0x0f;
284 *bp++ = Base64Code[c1];
285 c1 = (c2 & 0x0f) << 2;
286 if (p >= data + len) {
287 *bp++ = Base64Code[c1];
288 break;
289 }
290 c2 = *p++;
291 c1 |= (c2 >> 6) & 0x03;
292 *bp++ = Base64Code[c1];
293 *bp++ = Base64Code[c2 & 0x3f];
294 }
295 *bp = '\0';
296 }
297 #if 0
298 void
299 main()
300 {
301 char blubber[73];
302 char salt[100];
303 char *p;
304 salt[0] = '$';
305 salt[1] = BCRYPT_VERSION;
306 salt[2] = '$';
307
308 snprintf(salt + 3, 4, "%2.2u$", 5);
309
310 printf("24 bytes of salt: ");
311 fgets(salt + 6, sizeof(salt) - 6, stdin);
312 salt[99] = 0;
313 printf("72 bytes of password: ");
314 fpurge(stdin);
315 fgets(blubber, sizeof(blubber), stdin);
316 blubber[72] = 0;
317
318 p = crypt(blubber, salt);
319 printf("Passwd entry: %s\n\n", p);
320
321 p = bcrypt_gensalt(5);
322 printf("Generated salt: %s\n", p);
323 p = crypt(blubber, p);
324 printf("Passwd entry: %s\n", p);
325 }
326 #endif
327