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 /* 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)
39 * 3. REPEAT rounds:
40 * state := ExpandKey (state, 0, password)
41 * state := ExpandKey (state, 0, salt)
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 * and updated by Xin Li <delphij@FreeBSD.org>
52 */
53
54 #include <stdio.h>
55 #include <stdlib.h>
56 #include <sys/types.h>
57 #include <string.h>
58 #include <pwd.h>
59 #include "blowfish.h"
60 #include "crypt.h"
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_BLOCKS 6 /* Ciphertext blocks */
70 #define BCRYPT_MINLOGROUNDS 4 /* we have log2(rounds) in salt */
71
72
73 static void encode_base64(u_int8_t *, u_int8_t *, u_int16_t);
74 static void decode_base64(u_int8_t *, u_int16_t, const u_int8_t *);
75
76 const static u_int8_t Base64Code[] =
77 "./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
78
79 const static u_int8_t index_64[128] = {
80 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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, 0, 1, 54, 55,
85 56, 57, 58, 59, 60, 61, 62, 63, 255, 255,
86 255, 255, 255, 255, 255, 2, 3, 4, 5, 6,
87 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
88 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27,
89 255, 255, 255, 255, 255, 255, 28, 29, 30,
90 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
91 41, 42, 43, 44, 45, 46, 47, 48, 49, 50,
92 51, 52, 53, 255, 255, 255, 255, 255
93 };
94 #define CHAR64(c) ( (c) > 127 ? 255 : index_64[(c)])
95
96 static void
decode_base64(u_int8_t * buffer,u_int16_t len,const u_int8_t * data)97 decode_base64(u_int8_t *buffer, u_int16_t len, const u_int8_t *data)
98 {
99 u_int8_t *bp = buffer;
100 const u_int8_t *p = data;
101 u_int8_t c1, c2, c3, c4;
102 while (bp < buffer + len) {
103 c1 = CHAR64(*p);
104 c2 = CHAR64(*(p + 1));
105
106 /* Invalid data */
107 if (c1 == 255 || c2 == 255)
108 break;
109
110 *bp++ = (c1 << 2) | ((c2 & 0x30) >> 4);
111 if (bp >= buffer + len)
112 break;
113
114 c3 = CHAR64(*(p + 2));
115 if (c3 == 255)
116 break;
117
118 *bp++ = ((c2 & 0x0f) << 4) | ((c3 & 0x3c) >> 2);
119 if (bp >= buffer + len)
120 break;
121
122 c4 = CHAR64(*(p + 3));
123 if (c4 == 255)
124 break;
125 *bp++ = ((c3 & 0x03) << 6) | c4;
126
127 p += 4;
128 }
129 }
130
131 /* We handle $Vers$log2(NumRounds)$salt+passwd$
132 i.e. $2$04$iwouldntknowwhattosayetKdJ6iFtacBqJdKe6aW7ou */
133
134 int
crypt_blowfish(const char * key,const char * salt,char * buffer)135 crypt_blowfish(const char *key, const char *salt, char *buffer)
136 {
137 blf_ctx state;
138 u_int32_t rounds, i, k;
139 u_int16_t j;
140 size_t key_len;
141 u_int8_t 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 char arounds[3];
146
147 /* Defaults */
148 minr = 'b';
149 logr = BCRYPT_MINLOGROUNDS;
150 rounds = 1U << logr;
151
152 if (*salt == '$') {
153 /* Discard "$" identifier */
154 salt++;
155
156 if (*salt > BCRYPT_VERSION)
157 return (-1);
158
159 /* Check for minor versions */
160 if (salt[1] != '$') {
161 switch (salt[1]) {
162 case 'a': /* 'ab' should not yield the same as 'abab' */
163 case 'b': /* cap input length at 72 bytes */
164 case 'y': /* same as 'b', for compatibility
165 * with openwall crypt_blowfish
166 */
167 minr = salt[1];
168 salt++;
169 break;
170 default:
171 return (-1);
172 }
173 } else
174 minr = 0;
175
176 /* Discard version + "$" identifier */
177 salt += 2;
178
179 if (salt[2] != '$')
180 /* Out of sync with passwd entry */
181 return (-1);
182
183 memcpy(arounds, salt, sizeof(arounds));
184 if (arounds[sizeof(arounds) - 1] != '$')
185 return (-1);
186 arounds[sizeof(arounds) - 1] = 0;
187 logr = strtonum(arounds, BCRYPT_MINLOGROUNDS, 31, NULL);
188 if (logr == 0)
189 return (-1);
190 /* Computer power doesn't increase linearly, 2^x should be fine */
191 rounds = 1U << logr;
192
193 /* Discard num rounds + "$" identifier */
194 salt += 3;
195 }
196
197 if (strlen(salt) * 3 / 4 < BCRYPT_MAXSALT)
198 return (-1);
199
200 /* We dont want the base64 salt but the raw data */
201 decode_base64(csalt, BCRYPT_MAXSALT, (const u_int8_t *) salt);
202 salt_len = BCRYPT_MAXSALT;
203 if (minr <= 'a')
204 key_len = (u_int8_t)(strlen(key) + (minr >= 'a' ? 1 : 0));
205 else {
206 /* strlen() returns a size_t, but the function calls
207 * below result in implicit casts to a narrower integer
208 * type, so cap key_len at the actual maximum supported
209 * length here to avoid integer wraparound */
210 key_len = strlen(key);
211 if (key_len > 72)
212 key_len = 72;
213 key_len++; /* include the NUL */
214 }
215
216 /* Setting up S-Boxes and Subkeys */
217 Blowfish_initstate(&state);
218 Blowfish_expandstate(&state, csalt, salt_len,
219 (const u_int8_t *) key, key_len);
220 for (k = 0; k < rounds; k++) {
221 Blowfish_expand0state(&state, (const u_int8_t *) key, key_len);
222 Blowfish_expand0state(&state, csalt, salt_len);
223 }
224
225 /* This can be precomputed later */
226 j = 0;
227 for (i = 0; i < BCRYPT_BLOCKS; i++)
228 cdata[i] = Blowfish_stream2word(ciphertext, 4 * BCRYPT_BLOCKS, &j);
229
230 /* Now do the encryption */
231 for (k = 0; k < 64; k++)
232 blf_enc(&state, cdata, BCRYPT_BLOCKS / 2);
233
234 for (i = 0; i < BCRYPT_BLOCKS; i++) {
235 ciphertext[4 * i + 3] = cdata[i] & 0xff;
236 cdata[i] = cdata[i] >> 8;
237 ciphertext[4 * i + 2] = cdata[i] & 0xff;
238 cdata[i] = cdata[i] >> 8;
239 ciphertext[4 * i + 1] = cdata[i] & 0xff;
240 cdata[i] = cdata[i] >> 8;
241 ciphertext[4 * i + 0] = cdata[i] & 0xff;
242 }
243
244
245 *buffer++ = '$';
246 *buffer++ = BCRYPT_VERSION;
247 if (minr)
248 *buffer++ = minr;
249 *buffer++ = '$';
250
251 snprintf(buffer, 4, "%2.2u$", logr);
252 buffer += 3;
253
254 encode_base64((u_int8_t *)buffer, csalt, BCRYPT_MAXSALT);
255 buffer += strlen(buffer);
256 encode_base64((u_int8_t *)buffer, ciphertext, 4 * BCRYPT_BLOCKS - 1);
257 memset(&state, 0, sizeof(state));
258 memset(ciphertext, 0, sizeof(ciphertext));
259 memset(csalt, 0, sizeof(csalt));
260 memset(cdata, 0, sizeof(cdata));
261 return (0);
262 }
263
264 static void
encode_base64(u_int8_t * buffer,u_int8_t * data,u_int16_t len)265 encode_base64(u_int8_t *buffer, u_int8_t *data, u_int16_t len)
266 {
267 u_int8_t *bp = buffer;
268 u_int8_t *p = data;
269 u_int8_t c1, c2;
270 while (p < data + len) {
271 c1 = *p++;
272 *bp++ = Base64Code[(c1 >> 2)];
273 c1 = (c1 & 0x03) << 4;
274 if (p >= data + len) {
275 *bp++ = Base64Code[c1];
276 break;
277 }
278 c2 = *p++;
279 c1 |= (c2 >> 4) & 0x0f;
280 *bp++ = Base64Code[c1];
281 c1 = (c2 & 0x0f) << 2;
282 if (p >= data + len) {
283 *bp++ = Base64Code[c1];
284 break;
285 }
286 c2 = *p++;
287 c1 |= (c2 >> 6) & 0x03;
288 *bp++ = Base64Code[c1];
289 *bp++ = Base64Code[c2 & 0x3f];
290 }
291 *bp = '\0';
292 }
293 #if 0
294 void
295 main()
296 {
297 char blubber[73];
298 char salt[100];
299 char *p;
300 salt[0] = '$';
301 salt[1] = BCRYPT_VERSION;
302 salt[2] = '$';
303
304 snprintf(salt + 3, 4, "%2.2u$", 5);
305
306 printf("24 bytes of salt: ");
307 fgets(salt + 6, sizeof(salt) - 6, stdin);
308 salt[99] = 0;
309 printf("72 bytes of password: ");
310 fpurge(stdin);
311 fgets(blubber, sizeof(blubber), stdin);
312 blubber[72] = 0;
313
314 p = crypt(blubber, salt);
315 printf("Passwd entry: %s\n\n", p);
316
317 p = bcrypt_gensalt(5);
318 printf("Generated salt: %s\n", p);
319 p = crypt(blubber, p);
320 printf("Passwd entry: %s\n", p);
321 }
322 #endif
323