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
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
80 const static u_int8_t Base64Code[] =
81 "./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
82
83 const static u_int8_t index_64[128] = {
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, 255, 255, 255, 255,
87 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
88 255, 255, 255, 255, 255, 255, 0, 1, 54, 55,
89 56, 57, 58, 59, 60, 61, 62, 63, 255, 255,
90 255, 255, 255, 255, 255, 2, 3, 4, 5, 6,
91 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
92 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27,
93 255, 255, 255, 255, 255, 255, 28, 29, 30,
94 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
95 41, 42, 43, 44, 45, 46, 47, 48, 49, 50,
96 51, 52, 53, 255, 255, 255, 255, 255
97 };
98 #define CHAR64(c) ( (c) > 127 ? 255 : index_64[(c)])
99
100 static void
decode_base64(u_int8_t * buffer,u_int16_t len,const u_int8_t * data)101 decode_base64(u_int8_t *buffer, u_int16_t len, const u_int8_t *data)
102 {
103 u_int8_t *bp = buffer;
104 const u_int8_t *p = data;
105 u_int8_t c1, c2, c3, c4;
106 while (bp < buffer + len) {
107 c1 = CHAR64(*p);
108 c2 = CHAR64(*(p + 1));
109
110 /* Invalid data */
111 if (c1 == 255 || c2 == 255)
112 break;
113
114 *bp++ = (c1 << 2) | ((c2 & 0x30) >> 4);
115 if (bp >= buffer + len)
116 break;
117
118 c3 = CHAR64(*(p + 2));
119 if (c3 == 255)
120 break;
121
122 *bp++ = ((c2 & 0x0f) << 4) | ((c3 & 0x3c) >> 2);
123 if (bp >= buffer + len)
124 break;
125
126 c4 = CHAR64(*(p + 3));
127 if (c4 == 255)
128 break;
129 *bp++ = ((c3 & 0x03) << 6) | c4;
130
131 p += 4;
132 }
133 }
134
135 /* We handle $Vers$log2(NumRounds)$salt+passwd$
136 i.e. $2$04$iwouldntknowwhattosayetKdJ6iFtacBqJdKe6aW7ou */
137
138 char *
crypt_blowfish(const char * key,const char * salt)139 crypt_blowfish(const char *key, const char *salt)
140 {
141 blf_ctx state;
142 u_int32_t rounds, i, k;
143 u_int16_t j;
144 size_t key_len;
145 u_int8_t salt_len, logr, minr;
146 u_int8_t ciphertext[4 * BCRYPT_BLOCKS] = "OrpheanBeholderScryDoubt";
147 u_int8_t csalt[BCRYPT_MAXSALT];
148 u_int32_t cdata[BCRYPT_BLOCKS];
149 char arounds[3];
150
151 /* Defaults */
152 minr = 'b';
153 logr = BCRYPT_MINLOGROUNDS;
154 rounds = 1U << logr;
155
156 if (*salt == '$') {
157 /* Discard "$" identifier */
158 salt++;
159
160 if (*salt > BCRYPT_VERSION) {
161 /* How do I handle errors ? Return NULL */
162 return NULL;
163 }
164
165 /* Check for minor versions */
166 if (salt[1] != '$') {
167 switch (salt[1]) {
168 case 'a': /* 'ab' should not yield the same as 'abab' */
169 case 'b': /* cap input length at 72 bytes */
170 case 'y': /* same as 'b', for compatibility
171 * with openwall crypt_blowfish
172 */
173 minr = salt[1];
174 salt++;
175 break;
176 default:
177 return NULL;
178 }
179 } else
180 minr = 0;
181
182 /* Discard version + "$" identifier */
183 salt += 2;
184
185 if (salt[2] != '$')
186 /* Out of sync with passwd entry */
187 return NULL;
188
189 memcpy(arounds, salt, sizeof(arounds));
190 if (arounds[sizeof(arounds) - 1] != '$')
191 return NULL;
192 arounds[sizeof(arounds) - 1] = 0;
193 logr = strtonum(arounds, BCRYPT_MINLOGROUNDS, 31, NULL);
194 if (logr == 0)
195 return NULL;
196 /* Computer power doesn't increase linearly, 2^x should be fine */
197 rounds = 1U << logr;
198
199 /* Discard num rounds + "$" identifier */
200 salt += 3;
201 }
202
203 if (strlen(salt) * 3 / 4 < BCRYPT_MAXSALT)
204 return NULL;
205
206 /* We dont want the base64 salt but the raw data */
207 decode_base64(csalt, BCRYPT_MAXSALT, (const u_int8_t *) salt);
208 salt_len = BCRYPT_MAXSALT;
209 if (minr <= 'a')
210 key_len = (u_int8_t)(strlen(key) + (minr >= 'a' ? 1 : 0));
211 else {
212 /* strlen() returns a size_t, but the function calls
213 * below result in implicit casts to a narrower integer
214 * type, so cap key_len at the actual maximum supported
215 * length here to avoid integer wraparound */
216 key_len = strlen(key);
217 if (key_len > 72)
218 key_len = 72;
219 key_len++; /* include the NUL */
220 }
221
222 /* Setting up S-Boxes and Subkeys */
223 Blowfish_initstate(&state);
224 Blowfish_expandstate(&state, csalt, salt_len,
225 (const u_int8_t *) key, key_len);
226 for (k = 0; k < rounds; k++) {
227 Blowfish_expand0state(&state, (const u_int8_t *) key, key_len);
228 Blowfish_expand0state(&state, csalt, salt_len);
229 }
230
231 /* This can be precomputed later */
232 j = 0;
233 for (i = 0; i < BCRYPT_BLOCKS; i++)
234 cdata[i] = Blowfish_stream2word(ciphertext, 4 * BCRYPT_BLOCKS, &j);
235
236 /* Now do the encryption */
237 for (k = 0; k < 64; k++)
238 blf_enc(&state, cdata, BCRYPT_BLOCKS / 2);
239
240 for (i = 0; i < BCRYPT_BLOCKS; i++) {
241 ciphertext[4 * i + 3] = cdata[i] & 0xff;
242 cdata[i] = cdata[i] >> 8;
243 ciphertext[4 * i + 2] = cdata[i] & 0xff;
244 cdata[i] = cdata[i] >> 8;
245 ciphertext[4 * i + 1] = cdata[i] & 0xff;
246 cdata[i] = cdata[i] >> 8;
247 ciphertext[4 * i + 0] = cdata[i] & 0xff;
248 }
249
250
251 i = 0;
252 encrypted[i++] = '$';
253 encrypted[i++] = BCRYPT_VERSION;
254 if (minr)
255 encrypted[i++] = minr;
256 encrypted[i++] = '$';
257
258 snprintf(encrypted + i, 4, "%2.2u$", logr);
259
260 encode_base64((u_int8_t *) encrypted + i + 3, csalt, BCRYPT_MAXSALT);
261 encode_base64((u_int8_t *) encrypted + strlen(encrypted), ciphertext,
262 4 * BCRYPT_BLOCKS - 1);
263 memset(&state, 0, sizeof(state));
264 memset(ciphertext, 0, sizeof(ciphertext));
265 memset(csalt, 0, sizeof(csalt));
266 memset(cdata, 0, sizeof(cdata));
267 return encrypted;
268 }
269
270 static void
encode_base64(u_int8_t * buffer,u_int8_t * data,u_int16_t len)271 encode_base64(u_int8_t *buffer, u_int8_t *data, u_int16_t len)
272 {
273 u_int8_t *bp = buffer;
274 u_int8_t *p = data;
275 u_int8_t c1, c2;
276 while (p < data + len) {
277 c1 = *p++;
278 *bp++ = Base64Code[(c1 >> 2)];
279 c1 = (c1 & 0x03) << 4;
280 if (p >= data + len) {
281 *bp++ = Base64Code[c1];
282 break;
283 }
284 c2 = *p++;
285 c1 |= (c2 >> 4) & 0x0f;
286 *bp++ = Base64Code[c1];
287 c1 = (c2 & 0x0f) << 2;
288 if (p >= data + len) {
289 *bp++ = Base64Code[c1];
290 break;
291 }
292 c2 = *p++;
293 c1 |= (c2 >> 6) & 0x03;
294 *bp++ = Base64Code[c1];
295 *bp++ = Base64Code[c2 & 0x3f];
296 }
297 *bp = '\0';
298 }
299 #if 0
300 void
301 main()
302 {
303 char blubber[73];
304 char salt[100];
305 char *p;
306 salt[0] = '$';
307 salt[1] = BCRYPT_VERSION;
308 salt[2] = '$';
309
310 snprintf(salt + 3, 4, "%2.2u$", 5);
311
312 printf("24 bytes of salt: ");
313 fgets(salt + 6, sizeof(salt) - 6, stdin);
314 salt[99] = 0;
315 printf("72 bytes of password: ");
316 fpurge(stdin);
317 fgets(blubber, sizeof(blubber), stdin);
318 blubber[72] = 0;
319
320 p = crypt(blubber, salt);
321 printf("Passwd entry: %s\n\n", p);
322
323 p = bcrypt_gensalt(5);
324 printf("Generated salt: %s\n", p);
325 p = crypt(blubber, p);
326 printf("Passwd entry: %s\n", p);
327 }
328 #endif
329