1 /* 2 * Copyright 1997 Niels Provos <provos@physnet.uni-hamburg.de> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by Niels Provos. 16 * 4. The name of the author may not be used to endorse or promote products 17 * derived from this software without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 */ 30 31 #include <sys/cdefs.h> 32 __FBSDID("$FreeBSD$"); 33 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) 3. 39 * REPEAT rounds: 40 * state := ExpandKey (state, 0, salt) 41 * state := ExpandKey(state, 0, password) 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 */ 52 53 #include <stdio.h> 54 #include <stdlib.h> 55 #include <sys/types.h> 56 #include <string.h> 57 #include <pwd.h> 58 #include "blowfish.h" 59 #include "crypt.h" 60 61 /* This implementation is adaptable to current computing power. 62 * You can have up to 2^31 rounds which should be enough for some 63 * time to come. 64 */ 65 66 #define BCRYPT_VERSION '2' 67 #define BCRYPT_MAXSALT 16 /* Precomputation is just so nice */ 68 #define BCRYPT_BLOCKS 6 /* Ciphertext blocks */ 69 #define BCRYPT_MINROUNDS 16 /* we have log2(rounds) in salt */ 70 71 char *bcrypt_gensalt(u_int8_t); 72 73 static void encode_salt(char *, u_int8_t *, u_int16_t, u_int8_t); 74 static void encode_base64(u_int8_t *, u_int8_t *, u_int16_t); 75 static void decode_base64(u_int8_t *, u_int16_t, const u_int8_t *); 76 77 static char encrypted[_PASSWORD_LEN]; 78 static char gsalt[BCRYPT_MAXSALT * 4 / 3 + 1]; 79 static char error[] = ":"; 80 81 static const u_int8_t Base64Code[] = 82 "./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"; 83 84 static const u_int8_t index_64[128] = 85 { 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, 255, 255, 255, 255, 89 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 90 255, 255, 255, 255, 255, 255, 0, 1, 54, 55, 91 56, 57, 58, 59, 60, 61, 62, 63, 255, 255, 92 255, 255, 255, 255, 255, 2, 3, 4, 5, 6, 93 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 94 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 95 255, 255, 255, 255, 255, 255, 28, 29, 30, 96 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 97 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 98 51, 52, 53, 255, 255, 255, 255, 255 99 }; 100 #define CHAR64(c) ( (c) > 127 ? 255 : index_64[(c)]) 101 102 static void 103 decode_base64(u_int8_t *buffer, u_int16_t len, const u_int8_t *data) 104 { 105 u_int8_t *bp = buffer; 106 const u_int8_t *p = data; 107 u_int8_t c1, c2, c3, c4; 108 while (bp < buffer + len) { 109 c1 = CHAR64(*p); 110 c2 = CHAR64(*(p + 1)); 111 112 /* Invalid data */ 113 if (c1 == 255 || c2 == 255) 114 break; 115 116 *bp++ = (u_int8_t)((c1 << 2) | ((c2 & 0x30) >> 4)); 117 if (bp >= buffer + len) 118 break; 119 120 c3 = CHAR64(*(p + 2)); 121 if (c3 == 255) 122 break; 123 124 *bp++ = ((c2 & 0x0f) << 4) | ((c3 & 0x3c) >> 2); 125 if (bp >= buffer + len) 126 break; 127 128 c4 = CHAR64(*(p + 3)); 129 if (c4 == 255) 130 break; 131 *bp++ = ((c3 & 0x03) << 6) | c4; 132 133 p += 4; 134 } 135 } 136 137 static void 138 encode_salt(char *salt, u_int8_t *csalt, u_int16_t clen, u_int8_t logr) 139 { 140 salt[0] = '$'; 141 salt[1] = BCRYPT_VERSION; 142 salt[2] = 'a'; 143 salt[3] = '$'; 144 145 snprintf(salt + 4, 4, "%2.2u$", logr); 146 147 encode_base64((u_int8_t *) salt + 7, csalt, clen); 148 } 149 /* Generates a salt for this version of crypt. 150 Since versions may change. Keeping this here 151 seems sensible. 152 */ 153 154 char * 155 bcrypt_gensalt(u_int8_t log_rounds) 156 { 157 u_int8_t csalt[BCRYPT_MAXSALT]; 158 u_int16_t i; 159 u_int32_t seed = 0; 160 161 for (i = 0; i < BCRYPT_MAXSALT; i++) { 162 if (i % 4 == 0) 163 seed = arc4random(); 164 csalt[i] = seed & 0xff; 165 seed = seed >> 8; 166 } 167 168 if (log_rounds < 4) 169 log_rounds = 4; 170 171 encode_salt(gsalt, csalt, BCRYPT_MAXSALT, log_rounds); 172 return gsalt; 173 } 174 /* We handle $Vers$log2(NumRounds)$salt+passwd$ 175 i.e. $2$04$iwouldntknowwhattosayetKdJ6iFtacBqJdKe6aW7ou */ 176 177 char * 178 crypt_blowfish(const char *key, const char *salt) 179 { 180 blf_ctx state; 181 u_int32_t rounds, i, k; 182 u_int16_t j; 183 u_int8_t key_len, salt_len, logr, minr; 184 u_int8_t ciphertext[4 * BCRYPT_BLOCKS] = "OrpheanBeholderScryDoubt"; 185 u_int8_t csalt[BCRYPT_MAXSALT]; 186 u_int32_t cdata[BCRYPT_BLOCKS]; 187 static const char *magic = "$2a$04$"; 188 189 /* Defaults */ 190 minr = 'a'; 191 logr = 4; 192 rounds = 1 << logr; 193 194 /* If it starts with the magic string, then skip that */ 195 if(!strncmp(salt, magic, strlen(magic))) { 196 salt += strlen(magic); 197 } 198 else if (*salt == '$') { 199 200 /* Discard "$" identifier */ 201 salt++; 202 203 if (*salt > BCRYPT_VERSION) { 204 /* How do I handle errors ? Return ':' */ 205 return error; 206 } 207 208 /* Check for minor versions */ 209 if (salt[1] != '$') { 210 switch (salt[1]) { 211 case 'a': 212 /* 'ab' should not yield the same as 'abab' */ 213 minr = (u_int8_t)salt[1]; 214 salt++; 215 break; 216 default: 217 return error; 218 } 219 } else 220 minr = 0; 221 222 /* Discard version + "$" identifier */ 223 salt += 2; 224 225 if (salt[2] != '$') 226 /* Out of sync with passwd entry */ 227 return error; 228 229 /* Computer power doesnt increase linear, 2^x should be fine */ 230 logr = (u_int8_t)atoi(salt); 231 rounds = 1 << logr; 232 if (rounds < BCRYPT_MINROUNDS) 233 return error; 234 235 /* Discard num rounds + "$" identifier */ 236 salt += 3; 237 } 238 239 240 /* We dont want the base64 salt but the raw data */ 241 decode_base64(csalt, BCRYPT_MAXSALT, salt); 242 salt_len = BCRYPT_MAXSALT; 243 key_len = (u_int8_t)(strlen(key) + (minr >= 'a' ? 1 : 0)); 244 245 /* Setting up S-Boxes and Subkeys */ 246 Blowfish_initstate(&state); 247 Blowfish_expandstate(&state, csalt, salt_len, 248 (const u_int8_t *) key, key_len); 249 for (k = 0; k < rounds; k++) { 250 Blowfish_expand0state(&state, (const u_int8_t *) key, key_len); 251 Blowfish_expand0state(&state, csalt, salt_len); 252 } 253 254 /* This can be precomputed later */ 255 j = 0; 256 for (i = 0; i < BCRYPT_BLOCKS; i++) 257 cdata[i] = Blowfish_stream2word(ciphertext, 4 * BCRYPT_BLOCKS, &j); 258 259 /* Now do the encryption */ 260 for (k = 0; k < 64; k++) 261 blf_enc(&state, cdata, BCRYPT_BLOCKS / 2); 262 263 for (i = 0; i < BCRYPT_BLOCKS; i++) { 264 ciphertext[4 * i + 3] = cdata[i] & 0xff; 265 cdata[i] = cdata[i] >> 8; 266 ciphertext[4 * i + 2] = cdata[i] & 0xff; 267 cdata[i] = cdata[i] >> 8; 268 ciphertext[4 * i + 1] = cdata[i] & 0xff; 269 cdata[i] = cdata[i] >> 8; 270 ciphertext[4 * i + 0] = cdata[i] & 0xff; 271 } 272 273 274 i = 0; 275 encrypted[i++] = '$'; 276 encrypted[i++] = BCRYPT_VERSION; 277 if (minr) 278 encrypted[i++] = (int8_t)minr; 279 encrypted[i++] = '$'; 280 281 snprintf(encrypted + i, 4, "%2.2u$", logr); 282 283 encode_base64((u_int8_t *) encrypted + i + 3, csalt, BCRYPT_MAXSALT); 284 encode_base64((u_int8_t *) encrypted + strlen(encrypted), ciphertext, 285 4 * BCRYPT_BLOCKS - 1); 286 return encrypted; 287 } 288 289 static void 290 encode_base64(u_int8_t *buffer, u_int8_t *data, u_int16_t len) 291 { 292 u_int8_t *bp = buffer; 293 u_int8_t *p = data; 294 u_int8_t c1, c2; 295 while (p < data + len) { 296 c1 = *p++; 297 *bp++ = Base64Code[(c1 >> 2)]; 298 c1 = (c1 & 0x03) << 4; 299 if (p >= data + len) { 300 *bp++ = Base64Code[c1]; 301 break; 302 } 303 c2 = *p++; 304 c1 |= (c2 >> 4) & 0x0f; 305 *bp++ = Base64Code[c1]; 306 c1 = (c2 & 0x0f) << 2; 307 if (p >= data + len) { 308 *bp++ = Base64Code[c1]; 309 break; 310 } 311 c2 = *p++; 312 c1 |= (c2 >> 6) & 0x03; 313 *bp++ = Base64Code[c1]; 314 *bp++ = Base64Code[c2 & 0x3f]; 315 } 316 *bp = '\0'; 317 } 318 319 #if 0 320 void 321 main() 322 { 323 char blubber[73]; 324 char salt[100]; 325 char *p; 326 salt[0] = '$'; 327 salt[1] = BCRYPT_VERSION; 328 salt[2] = '$'; 329 330 snprintf(salt + 3, 4, "%2.2u$", 5); 331 332 printf("24 bytes of salt: "); 333 fgets(salt + 6, 94, stdin); 334 salt[99] = 0; 335 printf("72 bytes of password: "); 336 fpurge(stdin); 337 fgets(blubber, 73, stdin); 338 blubber[72] = 0; 339 340 p = crypt(blubber, salt); 341 printf("Passwd entry: %s\n\n", p); 342 343 p = bcrypt_gensalt(5); 344 printf("Generated salt: %s\n", p); 345 p = crypt(blubber, p); 346 printf("Passwd entry: %s\n", p); 347 } 348 #endif 349