1 /* $NetBSD: bcrypt.c,v 1.1 2002/05/24 04:02:49 itojun Exp $ */ 2 /* $OpenBSD: bcrypt.c,v 1.16 2002/02/19 19:39:36 millert Exp $ */ 3 4 /* 5 * Copyright 1997 Niels Provos <provos@physnet.uni-hamburg.de> 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by Niels Provos. 19 * 4. The name of the author may not be used to endorse or promote products 20 * derived from this software without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32 */ 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 #if 0 50 #include <stdio.h> 51 #endif 52 53 #include <stdio.h> 54 #include <stdlib.h> 55 #include <sys/types.h> 56 #include <string.h> 57 #include <pwd.h> 58 59 #include "blf.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 static void encode_salt(char *, u_int8_t *, u_int16_t, u_int8_t); 72 static void encode_base64(u_int8_t *, u_int8_t *, u_int16_t); 73 static void decode_base64(u_int8_t *, u_int16_t, u_int8_t *); 74 75 char *__bcrypt(const char *, const char *); /* XXX */ 76 77 static char encrypted[_PASSWORD_LEN]; 78 static char gsalt[BCRYPT_MAXSALT * 4 / 3 + 1]; 79 static char error[] = ":"; 80 81 const static u_int8_t Base64Code[] = 82 "./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"; 83 84 const static 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, u_int8_t *data) 104 { 105 u_int8_t *bp = buffer; 106 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++ = (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 } 149 150 /* Generates a salt for this version of crypt. 151 Since versions may change. Keeping this here 152 seems sensible. 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 } 174 175 /* We handle $Vers$log2(NumRounds)$salt+passwd$ 176 i.e. $2$04$iwouldntknowwhattosayetKdJ6iFtacBqJdKe6aW7ou */ 177 178 char * 179 __bcrypt(key, salt) 180 const char *key; 181 const char *salt; 182 { 183 blf_ctx state; 184 u_int32_t rounds, i, k; 185 u_int16_t j; 186 u_int8_t key_len, salt_len, logr, minor; 187 u_int8_t ciphertext[4 * BCRYPT_BLOCKS] = "OrpheanBeholderScryDoubt"; 188 u_int8_t csalt[BCRYPT_MAXSALT]; 189 u_int32_t cdata[BCRYPT_BLOCKS]; 190 191 /* Discard "$" identifier */ 192 salt++; 193 194 if (*salt > BCRYPT_VERSION) { 195 /* How do I handle errors ? Return ':' */ 196 return error; 197 } 198 199 /* Check for minor versions */ 200 if (salt[1] != '$') { 201 switch (salt[1]) { 202 case 'a': 203 /* 'ab' should not yield the same as 'abab' */ 204 minor = salt[1]; 205 salt++; 206 break; 207 default: 208 return error; 209 } 210 } else 211 minor = 0; 212 213 /* Discard version + "$" identifier */ 214 salt += 2; 215 216 if (salt[2] != '$') 217 /* Out of sync with passwd entry */ 218 return error; 219 220 /* Computer power doesn't increase linear, 2^x should be fine */ 221 if ((rounds = (u_int32_t) 1 << (logr = atoi(salt))) < BCRYPT_MINROUNDS) 222 return error; 223 224 /* Discard num rounds + "$" identifier */ 225 salt += 3; 226 227 if (strlen(salt) * 3 / 4 < BCRYPT_MAXSALT) 228 return error; 229 230 /* We dont want the base64 salt but the raw data */ 231 decode_base64(csalt, BCRYPT_MAXSALT, (u_int8_t *) salt); 232 salt_len = BCRYPT_MAXSALT; 233 key_len = strlen(key) + (minor >= 'a' ? 1 : 0); 234 235 /* Setting up S-Boxes and Subkeys */ 236 Blowfish_initstate(&state); 237 Blowfish_expandstate(&state, csalt, salt_len, 238 (u_int8_t *) key, key_len); 239 for (k = 0; k < rounds; k++) { 240 Blowfish_expand0state(&state, (u_int8_t *) key, key_len); 241 Blowfish_expand0state(&state, csalt, salt_len); 242 } 243 244 /* This can be precomputed later */ 245 j = 0; 246 for (i = 0; i < BCRYPT_BLOCKS; i++) 247 cdata[i] = Blowfish_stream2word(ciphertext, 4 * BCRYPT_BLOCKS, &j); 248 249 /* Now do the encryption */ 250 for (k = 0; k < 64; k++) 251 blf_enc(&state, cdata, BCRYPT_BLOCKS / 2); 252 253 for (i = 0; i < BCRYPT_BLOCKS; i++) { 254 ciphertext[4 * i + 3] = cdata[i] & 0xff; 255 cdata[i] = cdata[i] >> 8; 256 ciphertext[4 * i + 2] = cdata[i] & 0xff; 257 cdata[i] = cdata[i] >> 8; 258 ciphertext[4 * i + 1] = cdata[i] & 0xff; 259 cdata[i] = cdata[i] >> 8; 260 ciphertext[4 * i + 0] = cdata[i] & 0xff; 261 } 262 263 264 i = 0; 265 encrypted[i++] = '$'; 266 encrypted[i++] = BCRYPT_VERSION; 267 if (minor) 268 encrypted[i++] = minor; 269 encrypted[i++] = '$'; 270 271 snprintf(encrypted + i, 4, "%2.2u$", logr); 272 273 encode_base64((u_int8_t *) encrypted + i + 3, csalt, BCRYPT_MAXSALT); 274 encode_base64((u_int8_t *) encrypted + strlen(encrypted), ciphertext, 275 4 * BCRYPT_BLOCKS - 1); 276 return encrypted; 277 } 278 279 static void 280 encode_base64(u_int8_t *buffer, u_int8_t *data, u_int16_t len) 281 { 282 u_int8_t *bp = buffer; 283 u_int8_t *p = data; 284 u_int8_t c1, c2; 285 while (p < data + len) { 286 c1 = *p++; 287 *bp++ = Base64Code[(c1 >> 2)]; 288 c1 = (c1 & 0x03) << 4; 289 if (p >= data + len) { 290 *bp++ = Base64Code[c1]; 291 break; 292 } 293 c2 = *p++; 294 c1 |= (c2 >> 4) & 0x0f; 295 *bp++ = Base64Code[c1]; 296 c1 = (c2 & 0x0f) << 2; 297 if (p >= data + len) { 298 *bp++ = Base64Code[c1]; 299 break; 300 } 301 c2 = *p++; 302 c1 |= (c2 >> 6) & 0x03; 303 *bp++ = Base64Code[c1]; 304 *bp++ = Base64Code[c2 & 0x3f]; 305 } 306 *bp = '\0'; 307 } 308 #if 0 309 void 310 main() 311 { 312 char blubber[73]; 313 char salt[100]; 314 char *p; 315 salt[0] = '$'; 316 salt[1] = BCRYPT_VERSION; 317 salt[2] = '$'; 318 319 snprintf(salt + 3, 4, "%2.2u$", 5); 320 321 printf("24 bytes of salt: "); 322 fgets(salt + 6, 94, stdin); 323 salt[99] = 0; 324 printf("72 bytes of password: "); 325 fpurge(stdin); 326 fgets(blubber, 73, stdin); 327 blubber[72] = 0; 328 329 p = crypt(blubber, salt); 330 printf("Passwd entry: %s\n\n", p); 331 332 p = bcrypt_gensalt(5); 333 printf("Generated salt: %s\n", p); 334 p = crypt(blubber, p); 335 printf("Passwd entry: %s\n", p); 336 } 337 #endif 338