1 /* $OpenBSD: bcrypt.c,v 1.5 1997/04/30 05:57:04 tholo Exp $ */ 2 /* 3 * Copyright 1997 Niels Provos <provos@physnet.uni-hamburg.de> 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. All advertising materials mentioning features or use of this software 15 * must display the following acknowledgement: 16 * This product includes software developed by Niels Provos. 17 * 4. The name of the author may not be used to endorse or promote products 18 * derived from this software without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 21 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 22 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 23 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 24 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 25 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 26 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 27 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 28 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 29 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /* This password hashing algorithm was designed by David Mazieres 33 * <dm@lcs.mit.edu> and works as follows: 34 * 35 * 1. state := InitState () 36 * 2. state := ExpandKey (state, salt, password) 3. 37 * REPEAT rounds: 38 * state := ExpandKey (state, 0, salt) 39 * state := ExpandKey(state, 0, password) 40 * 4. ctext := "OrpheanBeholderScryDoubt" 41 * 5. REPEAT 64: 42 * ctext := Encrypt_ECB (state, ctext); 43 * 6. RETURN Concatenate (salt, ctext); 44 * 45 */ 46 47 #ifdef TEST 48 #include <stdio.h> 49 #endif 50 51 #include <stdlib.h> 52 #include <sys/types.h> 53 #include <string.h> 54 #include <pwd.h> 55 #include <blf.h> 56 57 /* This implementation is adaptable to current computing power. 58 * You can have up to 2^31 rounds which should be enough for some 59 * time to come. 60 */ 61 62 #define BCRYPT_VERSION '2' 63 #define BCRYPT_MAXSALT 16 /* Precomputation is just so nice */ 64 #define BCRYPT_BLOCKS 6 /* Ciphertext blocks */ 65 #define BCRYPT_MINROUNDS 16 /* we have log2(rounds) in salt */ 66 67 char *bcrypt_gensalt __P((u_int8_t)); 68 69 static void encode_salt __P((char *, u_int8_t *, u_int16_t, u_int8_t)); 70 static void encode_base64 __P((u_int8_t *, u_int8_t *, u_int16_t)); 71 static void decode_base64 __P((u_int8_t *, u_int16_t, u_int8_t *)); 72 73 static char encrypted[_PASSWORD_LEN]; 74 static char gsalt[BCRYPT_MAXSALT * 4 / 3 + 1]; 75 static char error[] = ":"; 76 77 const static u_int8_t Base64Code[] = 78 "./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"; 79 80 const static u_int8_t index_64[128] = 81 { 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 #if __STDC__ 99 static void 100 decode_base64(u_int8_t *buffer, u_int16_t len, u_int8_t *data) 101 #else 102 static void 103 decode_base64(buffer, len, data) 104 u_int8_t *buffer; 105 u_int16_t len; 106 u_int8_t *data; 107 #endif 108 { 109 u_int8_t *bp = buffer; 110 u_int8_t *p = data; 111 u_int8_t c1, c2, c3, c4; 112 while (bp < buffer + len) { 113 c1 = CHAR64(*p); 114 c2 = CHAR64(*(p + 1)); 115 116 /* Invalid data */ 117 if (c1 == 255 || c2 == 255) 118 break; 119 120 *bp++ = (c1 << 2) | ((c2 & 0x30) >> 4); 121 if (bp >= buffer + len) 122 break; 123 124 c3 = CHAR64(*(p + 2)); 125 if (c3 == 255) 126 break; 127 128 *bp++ = ((c2 & 0x0f) << 4) | ((c3 & 0x3c) >> 2); 129 if (bp >= buffer + len) 130 break; 131 132 c4 = CHAR64(*(p + 3)); 133 if (c4 == 255) 134 break; 135 *bp++ = ((c3 & 0x03) << 6) | c4; 136 137 p += 4; 138 } 139 } 140 141 #if __STDC__ 142 static void 143 encode_salt(char *salt, u_int8_t *csalt, u_int16_t clen, u_int8_t logr) 144 #else 145 static void 146 encode_salt(salt, csalt, clen, logr) 147 char *salt; 148 u_int8_t *csalt; 149 u_int16_t clen; 150 u_int8_t logr; 151 #endif 152 { 153 salt[0] = '$'; 154 salt[1] = BCRYPT_VERSION; 155 salt[2] = '$'; 156 157 snprintf(salt + 3, 4, "%2.2u$", logr); 158 159 encode_base64((u_int8_t *) salt + 6, csalt, clen); 160 } 161 /* Generates a salt for this version of crypt. 162 Since versions may change. Keeping this here 163 seems sensible. 164 */ 165 166 #if __STDC__ 167 char * 168 bcrypt_gensalt(u_int8_t log_rounds) 169 #else 170 char * 171 bcrypt_gensalt(log_rounds) 172 u_int8_t log_rounds; 173 #endif 174 { 175 u_int8_t csalt[BCRYPT_MAXSALT]; 176 u_int16_t i; 177 u_int32_t seed = 0; 178 179 for (i = 0; i < BCRYPT_MAXSALT; i++) { 180 if (i % 4 == 0) 181 seed = arc4random(); 182 csalt[i] = seed & 0xff; 183 seed = seed >> 8; 184 } 185 186 if (log_rounds < 4) 187 log_rounds = 4; 188 189 encode_salt(gsalt, csalt, BCRYPT_MAXSALT, log_rounds); 190 return gsalt; 191 } 192 /* We handle $Vers$log2(NumRounds)$salt+passwd$ 193 i.e. $2$04$iwouldntknowwhattosayetKdJ6iFtacBqJdKe6aW7ou */ 194 195 char * 196 bcrypt(key, salt) 197 const char *key; 198 const char *salt; 199 { 200 blf_ctx state; 201 u_int32_t rounds, i, k; 202 u_int16_t j; 203 u_int8_t key_len, salt_len, logr; 204 u_int8_t ciphertext[4 * BCRYPT_BLOCKS] = "OrpheanBeholderScryDoubt"; 205 u_int8_t csalt[BCRYPT_MAXSALT]; 206 u_int32_t cdata[BCRYPT_BLOCKS]; 207 /* Discard "$" identifier */ 208 salt++; 209 210 if (*salt > BCRYPT_VERSION) { 211 /* How do I handle errors ? Return ':' */ 212 return error; 213 } 214 /* Discard version + "$" identifier */ 215 salt += 2; 216 217 if (*(salt + 2) != '$') 218 /* Out of sync with passwd entry */ 219 return error; 220 221 /* Computer power doesnt increase linear, 2^x should be fine */ 222 if ((rounds = (u_int32_t) 1 << (logr = atoi(salt))) < BCRYPT_MINROUNDS) 223 return error; 224 225 /* Discard num rounds + "$" identifier */ 226 salt += 3; 227 228 /* We dont want the base64 salt but the raw data */ 229 decode_base64(csalt, BCRYPT_MAXSALT, (u_int8_t *) salt); 230 salt_len = BCRYPT_MAXSALT; 231 key_len = strlen(key); 232 233 /* Setting up S-Boxes and Subkeys */ 234 Blowfish_initstate(&state); 235 Blowfish_expandstate(&state, csalt, salt_len, 236 (u_int8_t *) key, key_len); 237 for (k = 0; k < rounds; k++) { 238 Blowfish_expand0state(&state, (u_int8_t *) key, key_len); 239 Blowfish_expand0state(&state, csalt, salt_len); 240 } 241 242 /* This can be precomputed later */ 243 j = 0; 244 for (i = 0; i < BCRYPT_BLOCKS; i++) 245 cdata[i] = Blowfish_stream2word(ciphertext, 4 * BCRYPT_BLOCKS, &j); 246 247 /* Now do the encryption */ 248 for (k = 0; k < 64; k++) 249 blf_enc(&state, cdata, BCRYPT_BLOCKS / 2); 250 251 for (i = 0; i < BCRYPT_BLOCKS; i++) { 252 ciphertext[4 * i + 3] = cdata[i] & 0xff; 253 cdata[i] = cdata[i] >> 8; 254 ciphertext[4 * i + 2] = cdata[i] & 0xff; 255 cdata[i] = cdata[i] >> 8; 256 ciphertext[4 * i + 1] = cdata[i] & 0xff; 257 cdata[i] = cdata[i] >> 8; 258 ciphertext[4 * i + 0] = cdata[i] & 0xff; 259 } 260 261 262 encrypted[0] = '$'; 263 encrypted[1] = BCRYPT_VERSION; 264 encrypted[2] = '$'; 265 266 snprintf(encrypted + 3, 4, "%2.2u$", logr); 267 268 encode_base64((u_int8_t *) encrypted + 6, csalt, BCRYPT_MAXSALT); 269 encode_base64((u_int8_t *) encrypted + strlen(encrypted), ciphertext, 270 4 * BCRYPT_BLOCKS); 271 return encrypted; 272 } 273 274 #if __STDC__ 275 static void 276 encode_base64(u_int8_t *buffer, u_int8_t *data, u_int16_t len) 277 #else 278 static void 279 encode_base64(buffer, data, len) 280 u_int8_t *buffer; 281 u_int8_t *data; 282 u_int16_t len; 283 #endif 284 { 285 u_int8_t *bp = buffer; 286 u_int8_t *p = data; 287 u_int8_t c1, c2; 288 while (p < data + len) { 289 c1 = *p++; 290 *bp++ = Base64Code[(c1 >> 2)]; 291 c1 = (c1 & 0x03) << 4; 292 c2 = *p++; 293 if (p >= data + len) { 294 *bp++ = Base64Code[c1]; 295 break; 296 } 297 c1 |= (c2 >> 4) & 0x0f; 298 *bp++ = Base64Code[c1]; 299 c1 = (c2 & 0x0f) << 2; 300 c2 = *p++; 301 if (p >= data + len) { 302 *bp++ = Base64Code[c1]; 303 break; 304 } 305 c1 |= (c2 >> 6) & 0x03; 306 *bp++ = Base64Code[c1]; 307 *bp++ = Base64Code[c2 & 0x3f]; 308 } 309 *bp = '\0'; 310 } 311 #ifdef TEST 312 void 313 main() 314 { 315 char blubber[73]; 316 char salt[100]; 317 char *p; 318 salt[0] = '$'; 319 salt[1] = BCRYPT_VERSION; 320 salt[2] = '$'; 321 322 snprintf(salt + 3, 4, "%2.2u$", 5); 323 324 printf("24 bytes of salt: "); 325 fgets(salt + 6, 94, stdin); 326 salt[99] = 0; 327 printf("72 bytes of password: "); 328 fpurge(stdin); 329 fgets(blubber, 73, stdin); 330 blubber[72] = 0; 331 332 p = crypt(blubber, salt); 333 printf("Passwd entry: %s\n\n", p); 334 335 p = bcrypt_gensalt(5); 336 printf("Generated salt: %s\n", p); 337 p = crypt(blubber, p); 338 printf("Passwd entry: %s\n", p); 339 } 340 #endif 341