1 /* $NetBSD: bcrypt.c,v 1.19 2013/08/28 17:47:07 riastradh Exp $ */
2 /* $OpenBSD: bcrypt.c,v 1.16 2002/02/19 19:39:36 millert Exp $ */
3
4 /*
5 * Copyright 1997 Niels Provos <provos@physnet.uni-hamburg.de>
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by Niels Provos.
19 * 4. The name of the author may not be used to endorse or promote products
20 * derived from this software without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 */
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 #include <sys/cdefs.h>
49 __RCSID("$NetBSD: bcrypt.c,v 1.19 2013/08/28 17:47:07 riastradh Exp $");
50
51 #include <stdio.h>
52 #include <stdlib.h>
53 #include <sys/types.h>
54 #include <string.h>
55 #include <pwd.h>
56 #include <errno.h>
57 #include <limits.h>
58
59 #include "crypt.h"
60 #include "blowfish.c"
61
62 /* This implementation is adaptable to current computing power.
63 * You can have up to 2^31 rounds which should be enough for some
64 * time to come.
65 */
66
67 #define BCRYPT_VERSION '2'
68 #define BCRYPT_MAXSALT 16 /* Precomputation is just so nice */
69 #define BCRYPT_MAXSALTLEN (7 + (BCRYPT_MAXSALT * 4 + 2) / 3 + 1)
70 #define BCRYPT_BLOCKS 6 /* Ciphertext blocks */
71 #define BCRYPT_MINROUNDS 16 /* we have log2(rounds) in salt */
72
73 static void encode_salt(char *, u_int8_t *, u_int16_t, u_int8_t);
74 static void encode_base64(u_int8_t *, u_int8_t *, u_int16_t);
75 static void decode_base64(u_int8_t *, u_int16_t, const u_int8_t *);
76
77 char *__bcrypt(const char *, const char *); /* XXX */
78
79 static char encrypted[_PASSWORD_LEN];
80
81 static const u_int8_t Base64Code[] =
82 "./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
83
84 char *bcrypt_gensalt(u_int8_t);
85
86 static const u_int8_t index_64[128] =
87 {
88 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
89 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
90 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
91 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
92 255, 255, 255, 255, 255, 255, 0, 1, 54, 55,
93 56, 57, 58, 59, 60, 61, 62, 63, 255, 255,
94 255, 255, 255, 255, 255, 2, 3, 4, 5, 6,
95 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
96 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27,
97 255, 255, 255, 255, 255, 255, 28, 29, 30,
98 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
99 41, 42, 43, 44, 45, 46, 47, 48, 49, 50,
100 51, 52, 53, 255, 255, 255, 255, 255
101 };
102 #define CHAR64(c) ( (c) > 127 ? 255 : index_64[(c)])
103
104 static void
decode_base64(u_int8_t * buffer,u_int16_t len,const u_int8_t * data)105 decode_base64(u_int8_t *buffer, u_int16_t len, const u_int8_t *data)
106 {
107 u_int8_t *bp = buffer;
108 const u_int8_t *p = data;
109 u_int8_t c1, c2, c3, c4;
110 while (bp < buffer + len) {
111 c1 = CHAR64(*p);
112 c2 = CHAR64(*(p + 1));
113
114 /* Invalid data */
115 if (c1 == 255 || c2 == 255)
116 break;
117
118 *bp++ = ((u_int32_t)c1 << 2) | (((u_int32_t)c2 & 0x30) >> 4);
119 if (bp >= buffer + len)
120 break;
121
122 c3 = CHAR64(*(p + 2));
123 if (c3 == 255)
124 break;
125
126 *bp++ = (((u_int32_t)c2 & 0x0f) << 4) | (((uint32_t)c3 & 0x3c) >> 2);
127 if (bp >= buffer + len)
128 break;
129
130 c4 = CHAR64(*(p + 3));
131 if (c4 == 255)
132 break;
133 *bp++ = ((c3 & 0x03) << 6) | c4;
134
135 p += 4;
136 }
137 }
138
139 static void
encode_salt(char * salt,u_int8_t * csalt,u_int16_t clen,u_int8_t logr)140 encode_salt(char *salt, u_int8_t *csalt, u_int16_t clen, u_int8_t logr)
141 {
142 salt[0] = '$';
143 salt[1] = BCRYPT_VERSION;
144 salt[2] = 'a';
145 salt[3] = '$';
146
147 snprintf(salt + 4, 4, "%2.2u$", logr);
148
149 encode_base64((u_int8_t *) salt + 7, csalt, clen);
150 }
151
152 int
__gensalt_blowfish(char * salt,size_t saltlen,const char * option)153 __gensalt_blowfish(char *salt, size_t saltlen, const char *option)
154 {
155 size_t i;
156 u_int32_t seed = 0;
157 u_int8_t csalt[BCRYPT_MAXSALT];
158 unsigned long nrounds;
159 char *ep;
160
161 if (saltlen < BCRYPT_MAXSALTLEN) {
162 errno = ENOSPC;
163 return -1;
164 }
165 if (option == NULL) {
166 errno = EINVAL;
167 return -1;
168 }
169 nrounds = strtoul(option, &ep, 0);
170 if (option == ep || *ep) {
171 errno = EINVAL;
172 return -1;
173 }
174 if (errno == ERANGE && nrounds == ULONG_MAX)
175 return -1;
176
177 if (nrounds < 4)
178 nrounds = 4;
179 else if (nrounds > 31)
180 nrounds = 31;
181
182 for (i = 0; i < BCRYPT_MAXSALT; i++) {
183 if (i % 4 == 0)
184 seed = arc4random();
185 csalt[i] = seed & 0xff;
186 seed = seed >> 8;
187 }
188 encode_salt(salt, csalt, BCRYPT_MAXSALT, (u_int8_t)nrounds);
189 return 0;
190 }
191
192 /* Generates a salt for this version of crypt.
193 Since versions may change. Keeping this here
194 seems sensible.
195 XXX: compat.
196 */
197 char *
bcrypt_gensalt(u_int8_t log_rounds)198 bcrypt_gensalt(u_int8_t log_rounds)
199 {
200 static char gsalt[BCRYPT_MAXSALTLEN];
201 char num[10];
202
203 (void)snprintf(num, sizeof(num), "%d", log_rounds);
204 if (__gensalt_blowfish(gsalt, sizeof(gsalt), num) == -1)
205 return NULL;
206 return gsalt;
207 }
208
209 /* We handle $Vers$log2(NumRounds)$salt+passwd$
210 i.e. $2$04$iwouldntknowwhattosayetKdJ6iFtacBqJdKe6aW7ou */
211
212 char *
__bcrypt(const char * key,const char * salt)213 __bcrypt(const char *key, const char *salt)
214 {
215 blf_ctx state;
216 u_int32_t rounds, i, k;
217 u_int16_t j;
218 u_int8_t key_len, salt_len, logr, minor;
219 u_int8_t ciphertext[4 * BCRYPT_BLOCKS] = "OrpheanBeholderScryDoubt";
220 u_int8_t csalt[BCRYPT_MAXSALT];
221 u_int32_t cdata[BCRYPT_BLOCKS];
222 int n;
223 size_t len;
224
225 /* Discard "$" identifier */
226 salt++;
227
228 if (*salt > BCRYPT_VERSION)
229 return NULL;
230
231 /* Check for minor versions */
232 if (salt[1] != '$') {
233 switch (salt[1]) {
234 case 'a':
235 /* 'ab' should not yield the same as 'abab' */
236 minor = salt[1];
237 salt++;
238 break;
239 default:
240 return NULL;
241 }
242 } else
243 minor = 0;
244
245 /* Discard version + "$" identifier */
246 salt += 2;
247
248 if (salt[2] != '$')
249 /* Out of sync with passwd entry */
250 return NULL;
251
252 /* Computer power doesn't increase linear, 2^x should be fine */
253 n = atoi(salt);
254 if (n > 31 || n < 0)
255 return NULL;
256 logr = (u_int8_t)n;
257 if ((rounds = (u_int32_t) 1 << logr) < BCRYPT_MINROUNDS)
258 return NULL;
259
260 /* Discard num rounds + "$" identifier */
261 salt += 3;
262
263 if (strlen(salt) * 3 / 4 < BCRYPT_MAXSALT)
264 return NULL;
265
266 /* We dont want the base64 salt but the raw data */
267 decode_base64(csalt, BCRYPT_MAXSALT, (const u_int8_t *)salt);
268 salt_len = BCRYPT_MAXSALT;
269 len = strlen(key);
270 if (len > 72)
271 key_len = 72;
272 else
273 key_len = (uint8_t)len;
274 key_len += minor >= 'a' ? 1 : 0;
275
276 /* Setting up S-Boxes and Subkeys */
277 Blowfish_initstate(&state);
278 Blowfish_expandstate(&state, csalt, salt_len,
279 (const u_int8_t *) key, key_len);
280 for (k = 0; k < rounds; k++) {
281 Blowfish_expand0state(&state, (const u_int8_t *) key, key_len);
282 Blowfish_expand0state(&state, csalt, salt_len);
283 }
284
285 /* This can be precomputed later */
286 j = 0;
287 for (i = 0; i < BCRYPT_BLOCKS; i++)
288 cdata[i] = Blowfish_stream2word(ciphertext, 4 * BCRYPT_BLOCKS, &j);
289
290 /* Now do the encryption */
291 for (k = 0; k < 64; k++)
292 blf_enc(&state, cdata, BCRYPT_BLOCKS / 2);
293
294 for (i = 0; i < BCRYPT_BLOCKS; i++) {
295 ciphertext[4 * i + 3] = cdata[i] & 0xff;
296 cdata[i] = cdata[i] >> 8;
297 ciphertext[4 * i + 2] = cdata[i] & 0xff;
298 cdata[i] = cdata[i] >> 8;
299 ciphertext[4 * i + 1] = cdata[i] & 0xff;
300 cdata[i] = cdata[i] >> 8;
301 ciphertext[4 * i + 0] = cdata[i] & 0xff;
302 }
303
304
305 i = 0;
306 encrypted[i++] = '$';
307 encrypted[i++] = BCRYPT_VERSION;
308 if (minor)
309 encrypted[i++] = minor;
310 encrypted[i++] = '$';
311
312 snprintf(encrypted + i, 4, "%2.2u$", logr);
313
314 encode_base64((u_int8_t *) encrypted + i + 3, csalt, BCRYPT_MAXSALT);
315 encode_base64((u_int8_t *) encrypted + strlen(encrypted), ciphertext,
316 4 * BCRYPT_BLOCKS - 1);
317 explicit_memset(&state, 0, sizeof(state));
318 return encrypted;
319 }
320
321 static void
encode_base64(u_int8_t * buffer,u_int8_t * data,u_int16_t len)322 encode_base64(u_int8_t *buffer, u_int8_t *data, u_int16_t len)
323 {
324 u_int8_t *bp = buffer;
325 u_int8_t *p = data;
326 u_int8_t c1, c2;
327 while (p < data + len) {
328 c1 = *p++;
329 *bp++ = Base64Code[((u_int32_t)c1 >> 2)];
330 c1 = (c1 & 0x03) << 4;
331 if (p >= data + len) {
332 *bp++ = Base64Code[c1];
333 break;
334 }
335 c2 = *p++;
336 c1 |= ((u_int32_t)c2 >> 4) & 0x0f;
337 *bp++ = Base64Code[c1];
338 c1 = (c2 & 0x0f) << 2;
339 if (p >= data + len) {
340 *bp++ = Base64Code[c1];
341 break;
342 }
343 c2 = *p++;
344 c1 |= ((u_int32_t)c2 >> 6) & 0x03;
345 *bp++ = Base64Code[c1];
346 *bp++ = Base64Code[c2 & 0x3f];
347 }
348 *bp = '\0';
349 }
350 #if 0
351 void
352 main()
353 {
354 char blubber[73];
355 char salt[100];
356 char *p;
357 salt[0] = '$';
358 salt[1] = BCRYPT_VERSION;
359 salt[2] = '$';
360
361 snprintf(salt + 3, 4, "%2.2u$", 5);
362
363 printf("24 bytes of salt: ");
364 fgets(salt + 6, 94, stdin);
365 salt[99] = 0;
366 printf("72 bytes of password: ");
367 fpurge(stdin);
368 fgets(blubber, 73, stdin);
369 blubber[72] = 0;
370
371 p = crypt(blubber, salt);
372 printf("Passwd entry: %s\n\n", p);
373
374 p = bcrypt_gensalt(5);
375 printf("Generated salt: %s\n", p);
376 p = crypt(blubber, p);
377 printf("Passwd entry: %s\n", p);
378 }
379 #endif
380