1 /* $OpenBSD: bcrypt.c,v 1.29 2014/02/24 19:45:43 tedu Exp $ */
2
3 /*
4 * Copyright 1997 Niels Provos <[email protected]>
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 * <[email protected]> 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 <[email protected]>
53 * and updated by Xin Li <[email protected]>
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 const static u_int8_t Base64Code[] =
79 "./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
80
81 const 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
98 static void
decode_base64(u_int8_t * buffer,u_int16_t len,const u_int8_t * data)99 decode_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
136 int
crypt_blowfish(const char * key,const char * salt,char * buffer)137 crypt_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
266 static void
encode_base64(u_int8_t * buffer,u_int8_t * data,u_int16_t len)267 encode_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
296 void
297 main()
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