1 /* $OpenBSD: bcrypt.c,v 1.7 1997/07/09 01:08:18 millert 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 /* This password hashing algorithm was designed by David Mazieres 34 * <dm@lcs.mit.edu> and works as follows: 35 * 36 * 1. state := InitState () 37 * 2. state := ExpandKey (state, salt, password) 3. 38 * REPEAT rounds: 39 * state := ExpandKey (state, 0, salt) 40 * state := ExpandKey(state, 0, password) 41 * 4. ctext := "OrpheanBeholderScryDoubt" 42 * 5. REPEAT 64: 43 * ctext := Encrypt_ECB (state, ctext); 44 * 6. RETURN Concatenate (salt, ctext); 45 * 46 */ 47 48 #ifdef TEST 49 #include <stdio.h> 50 #endif 51 52 #include <stdio.h> 53 #include <stdlib.h> 54 #include <sys/types.h> 55 #include <string.h> 56 #include <pwd.h> 57 #include <blf.h> 58 59 /* This implementation is adaptable to current computing power. 60 * You can have up to 2^31 rounds which should be enough for some 61 * time to come. 62 */ 63 64 #define BCRYPT_VERSION '2' 65 #define BCRYPT_MAXSALT 16 /* Precomputation is just so nice */ 66 #define BCRYPT_BLOCKS 6 /* Ciphertext blocks */ 67 #define BCRYPT_MINROUNDS 16 /* we have log2(rounds) in salt */ 68 69 char *bcrypt_gensalt __P((u_int8_t)); 70 71 static void encode_salt __P((char *, u_int8_t *, u_int16_t, u_int8_t)); 72 static void encode_base64 __P((u_int8_t *, u_int8_t *, u_int16_t)); 73 static void decode_base64 __P((u_int8_t *, u_int16_t, u_int8_t *)); 74 75 static char encrypted[_PASSWORD_LEN]; 76 static char gsalt[BCRYPT_MAXSALT * 4 / 3 + 1]; 77 static char error[] = ":"; 78 79 const static u_int8_t Base64Code[] = 80 "./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"; 81 82 const static u_int8_t index_64[128] = 83 { 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 #if __STDC__ 101 static void 102 decode_base64(u_int8_t *buffer, u_int16_t len, u_int8_t *data) 103 #else 104 static void 105 decode_base64(buffer, len, data) 106 u_int8_t *buffer; 107 u_int16_t len; 108 u_int8_t *data; 109 #endif 110 { 111 u_int8_t *bp = buffer; 112 u_int8_t *p = data; 113 u_int8_t c1, c2, c3, c4; 114 while (bp < buffer + len) { 115 c1 = CHAR64(*p); 116 c2 = CHAR64(*(p + 1)); 117 118 /* Invalid data */ 119 if (c1 == 255 || c2 == 255) 120 break; 121 122 *bp++ = (c1 << 2) | ((c2 & 0x30) >> 4); 123 if (bp >= buffer + len) 124 break; 125 126 c3 = CHAR64(*(p + 2)); 127 if (c3 == 255) 128 break; 129 130 *bp++ = ((c2 & 0x0f) << 4) | ((c3 & 0x3c) >> 2); 131 if (bp >= buffer + len) 132 break; 133 134 c4 = CHAR64(*(p + 3)); 135 if (c4 == 255) 136 break; 137 *bp++ = ((c3 & 0x03) << 6) | c4; 138 139 p += 4; 140 } 141 } 142 143 #if __STDC__ 144 static void 145 encode_salt(char *salt, u_int8_t *csalt, u_int16_t clen, u_int8_t logr) 146 #else 147 static void 148 encode_salt(salt, csalt, clen, logr) 149 char *salt; 150 u_int8_t *csalt; 151 u_int16_t clen; 152 u_int8_t logr; 153 #endif 154 { 155 salt[0] = '$'; 156 salt[1] = BCRYPT_VERSION; 157 salt[2] = 'a'; 158 salt[3] = '$'; 159 160 snprintf(salt + 4, 4, "%2.2u$", logr); 161 162 encode_base64((u_int8_t *) salt + 7, csalt, clen); 163 } 164 /* Generates a salt for this version of crypt. 165 Since versions may change. Keeping this here 166 seems sensible. 167 */ 168 169 #if __STDC__ 170 char * 171 bcrypt_gensalt(u_int8_t log_rounds) 172 #else 173 char * 174 bcrypt_gensalt(log_rounds) 175 u_int8_t log_rounds; 176 #endif 177 { 178 u_int8_t csalt[BCRYPT_MAXSALT]; 179 u_int16_t i; 180 u_int32_t seed = 0; 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 } 188 189 if (log_rounds < 4) 190 log_rounds = 4; 191 192 encode_salt(gsalt, csalt, BCRYPT_MAXSALT, log_rounds); 193 return gsalt; 194 } 195 /* We handle $Vers$log2(NumRounds)$salt+passwd$ 196 i.e. $2$04$iwouldntknowwhattosayetKdJ6iFtacBqJdKe6aW7ou */ 197 198 char * 199 bcrypt(key, salt) 200 const char *key; 201 const char *salt; 202 { 203 blf_ctx state; 204 u_int32_t rounds, i, k; 205 u_int16_t j; 206 u_int8_t key_len, salt_len, logr, minor; 207 u_int8_t ciphertext[4 * BCRYPT_BLOCKS] = "OrpheanBeholderScryDoubt"; 208 u_int8_t csalt[BCRYPT_MAXSALT]; 209 u_int32_t cdata[BCRYPT_BLOCKS]; 210 211 /* Discard "$" identifier */ 212 salt++; 213 214 if (*salt > BCRYPT_VERSION) { 215 /* How do I handle errors ? Return ':' */ 216 return error; 217 } 218 219 /* Check for minor versions */ 220 if (salt[1] != '$') { 221 switch(salt[1]) { 222 case 'a': 223 /* 'ab' should not yield the same as 'abab' */ 224 minor = salt[1]; 225 salt++; 226 break; 227 default: 228 return error; 229 } 230 } else 231 minor = 0; 232 233 /* Discard version + "$" identifier */ 234 salt += 2; 235 236 if (salt[2] != '$') 237 /* Out of sync with passwd entry */ 238 return error; 239 240 /* Computer power doesnt increase linear, 2^x should be fine */ 241 if ((rounds = (u_int32_t) 1 << (logr = atoi(salt))) < BCRYPT_MINROUNDS) 242 return error; 243 244 /* Discard num rounds + "$" identifier */ 245 salt += 3; 246 247 /* We dont want the base64 salt but the raw data */ 248 decode_base64(csalt, BCRYPT_MAXSALT, (u_int8_t *) salt); 249 salt_len = BCRYPT_MAXSALT; 250 key_len = strlen(key) + (minor >= 'a' ? 1 : 0); 251 252 /* Setting up S-Boxes and Subkeys */ 253 Blowfish_initstate(&state); 254 Blowfish_expandstate(&state, csalt, salt_len, 255 (u_int8_t *) key, key_len); 256 for (k = 0; k < rounds; k++) { 257 Blowfish_expand0state(&state, (u_int8_t *) key, key_len); 258 Blowfish_expand0state(&state, csalt, salt_len); 259 } 260 261 /* This can be precomputed later */ 262 j = 0; 263 for (i = 0; i < BCRYPT_BLOCKS; i++) 264 cdata[i] = Blowfish_stream2word(ciphertext, 4 * BCRYPT_BLOCKS, &j); 265 266 /* Now do the encryption */ 267 for (k = 0; k < 64; k++) 268 blf_enc(&state, cdata, BCRYPT_BLOCKS / 2); 269 270 for (i = 0; i < BCRYPT_BLOCKS; i++) { 271 ciphertext[4 * i + 3] = cdata[i] & 0xff; 272 cdata[i] = cdata[i] >> 8; 273 ciphertext[4 * i + 2] = cdata[i] & 0xff; 274 cdata[i] = cdata[i] >> 8; 275 ciphertext[4 * i + 1] = cdata[i] & 0xff; 276 cdata[i] = cdata[i] >> 8; 277 ciphertext[4 * i + 0] = cdata[i] & 0xff; 278 } 279 280 281 i = 0; 282 encrypted[i++] = '$'; 283 encrypted[i++] = BCRYPT_VERSION; 284 if (minor) 285 encrypted[i++] = minor; 286 encrypted[i++] = '$'; 287 288 snprintf(encrypted + i, 4, "%2.2u$", logr); 289 290 encode_base64((u_int8_t *) encrypted + i + 3, csalt, BCRYPT_MAXSALT); 291 encode_base64((u_int8_t *) encrypted + strlen(encrypted), ciphertext, 292 4 * BCRYPT_BLOCKS); 293 return encrypted; 294 } 295 296 #if __STDC__ 297 static void 298 encode_base64(u_int8_t *buffer, u_int8_t *data, u_int16_t len) 299 #else 300 static void 301 encode_base64(buffer, data, len) 302 u_int8_t *buffer; 303 u_int8_t *data; 304 u_int16_t len; 305 #endif 306 { 307 u_int8_t *bp = buffer; 308 u_int8_t *p = data; 309 u_int8_t c1, c2; 310 while (p < data + len) { 311 c1 = *p++; 312 *bp++ = Base64Code[(c1 >> 2)]; 313 c1 = (c1 & 0x03) << 4; 314 c2 = *p++; 315 if (p >= data + len) { 316 *bp++ = Base64Code[c1]; 317 break; 318 } 319 c1 |= (c2 >> 4) & 0x0f; 320 *bp++ = Base64Code[c1]; 321 c1 = (c2 & 0x0f) << 2; 322 c2 = *p++; 323 if (p >= data + len) { 324 *bp++ = Base64Code[c1]; 325 break; 326 } 327 c1 |= (c2 >> 6) & 0x03; 328 *bp++ = Base64Code[c1]; 329 *bp++ = Base64Code[c2 & 0x3f]; 330 } 331 *bp = '\0'; 332 } 333 #ifdef TEST 334 void 335 main() 336 { 337 char blubber[73]; 338 char salt[100]; 339 char *p; 340 salt[0] = '$'; 341 salt[1] = BCRYPT_VERSION; 342 salt[2] = '$'; 343 344 snprintf(salt + 3, 4, "%2.2u$", 5); 345 346 printf("24 bytes of salt: "); 347 fgets(salt + 6, 94, stdin); 348 salt[99] = 0; 349 printf("72 bytes of password: "); 350 fpurge(stdin); 351 fgets(blubber, 73, stdin); 352 blubber[72] = 0; 353 354 p = crypt(blubber, salt); 355 printf("Passwd entry: %s\n\n", p); 356 357 p = bcrypt_gensalt(5); 358 printf("Generated salt: %s\n", p); 359 p = crypt(blubber, p); 360 printf("Passwd entry: %s\n", p); 361 } 362 #endif 363