1 /* $OpenBSD: bcrypt.c,v 1.2 1997/02/14 18:40:14 provos 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 Theo de Raadt. 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 := "OpenBSDbcrypthashfunc" 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 <time.h> 53 #include <sys/types.h> 54 #include <string.h> 55 #include <pwd.h> 56 #include <blf.h> 57 58 /* This implementation is adaptable to current computing power. 59 * You can have up to 2^31 rounds which should be enough for some 60 * time to come. 61 */ 62 63 #define BCRYPT_VERSION '2' 64 #define BCRYPT_MAXSALT 16 /* Precomputation is just so nice */ 65 #define BCRYPT_BLOCKS 6 /* Ciphertext blocks */ 66 #define BCRYPT_MINROUNDS 16 /* we have log2(rounds) in salt */ 67 68 char *bcrypt_gensalt __P((u_int8_t)); 69 70 static void encode_salt __P((char *, u_int8_t *, u_int16_t, u_int8_t)); 71 static void encode_base64 __P((u_int8_t *, u_int8_t *, u_int16_t)); 72 static void decode_base64 __P((u_int8_t *, u_int16_t, u_int8_t *)); 73 74 static char encrypted[_PASSWORD_LEN]; 75 static char gsalt[BCRYPT_MAXSALT * 4 / 3 + 1]; 76 static char error[] = ":"; 77 78 const static u_int8_t Base64Code[] = 79 "./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"; 80 81 const static u_int8_t index_64[128] = 82 { 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, 255, 255, 255, 255, 87 255, 255, 255, 255, 255, 255, 0, 1, 54, 55, 88 56, 57, 58, 59, 60, 61, 62, 63, 255, 255, 89 255, 255, 255, 255, 255, 2, 3, 4, 5, 6, 90 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 91 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 92 255, 255, 255, 255, 255, 255, 28, 29, 30, 93 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 94 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 95 51, 52, 53, 255, 255, 255, 255, 255 96 }; 97 #define CHAR64(c) ( (c) > 127 ? 255 : index_64[(c)]) 98 99 static void 100 decode_base64(buffer, len, data) 101 u_int8_t *buffer; 102 u_int16_t len; 103 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(salt, csalt, clen, logr) 139 char *salt; 140 u_int8_t *csalt; 141 u_int16_t clen; 142 u_int8_t logr; 143 { 144 salt[0] = '$'; 145 salt[1] = BCRYPT_VERSION; 146 salt[2] = '$'; 147 148 snprintf(salt + 3, 4, "%2.2u$", logr); 149 150 encode_base64((u_int8_t *) salt + 6, csalt, clen); 151 } 152 /* Generates a salt for this version of crypt. 153 Since versions may change. Keeping this here 154 seems sensible. 155 */ 156 157 char * 158 bcrypt_gensalt(log_rounds) 159 u_int8_t log_rounds; 160 { 161 u_int8_t csalt[BCRYPT_MAXSALT]; 162 u_int16_t i; 163 u_int32_t seed = 0; 164 (void) srandom((int) time((time_t *) NULL)); 165 for (i = 0; i < BCRYPT_MAXSALT; i++) { 166 if (i % 4 == 0) 167 seed = random(); 168 csalt[i] = seed & 0xff; 169 seed = seed >> 8; 170 } 171 172 if (log_rounds < 4) 173 log_rounds = 4; 174 175 encode_salt(gsalt, csalt, BCRYPT_MAXSALT, log_rounds); 176 return gsalt; 177 } 178 /* We handle $Vers$log2(NumRounds)$salt+passwd$ 179 i.e. $2$04$iwouldntknowwhattosayetKdJ6iFtacBqJdKe6aW7ou */ 180 181 char * 182 bcrypt(key, salt) 183 char *key; 184 char *salt; 185 { 186 blf_ctx state; 187 u_int32_t rounds, i, k; 188 u_int16_t j; 189 u_int8_t key_len, salt_len, logr; 190 u_int8_t ciphertext[4 * BCRYPT_BLOCKS] = "OpenBSDbcrypthashfunc"; 191 u_int8_t csalt[BCRYPT_MAXSALT]; 192 u_int32_t cdata[BCRYPT_BLOCKS]; 193 /* Discard "$" identifier */ 194 salt++; 195 196 if (*salt > BCRYPT_VERSION) { 197 /* How do I handle errors ? Return ':' */ 198 return error; 199 } 200 /* Discard version + "$" identifier */ 201 salt += 2; 202 203 if (*(salt + 2) != '$') 204 /* Out of sync with passwd entry */ 205 return error; 206 207 /* Computer power doesnt increase linear, 2^x should be fine */ 208 if ((rounds = (u_int32_t) 1 << (logr = atoi(salt))) < BCRYPT_MINROUNDS) 209 return error; 210 211 /* Discard num rounds + "$" identifier */ 212 salt += 3; 213 214 /* We dont want the base64 salt but the raw data */ 215 decode_base64(csalt, BCRYPT_MAXSALT, (u_int8_t *) salt); 216 salt_len = BCRYPT_MAXSALT; 217 key_len = strlen(key); 218 219 /* Setting up S-Boxes and Subkeys */ 220 Blowfish_initstate(&state); 221 Blowfish_expandstate(&state, csalt, salt_len, 222 (u_int8_t *) key, key_len); 223 for (k = 0; k < rounds; k++) { 224 Blowfish_expand0state(&state, (u_int8_t *) key, key_len); 225 Blowfish_expand0state(&state, csalt, salt_len); 226 } 227 228 /* This can be precomputed later */ 229 j = 0; 230 for (i = 0; i < BCRYPT_BLOCKS; i++) 231 cdata[i] = Blowfish_stream2word(ciphertext, 4 * BCRYPT_BLOCKS, &j); 232 233 /* Now do the encryption */ 234 for (k = 0; k < 64; k++) 235 blf_enc(&state, cdata, BCRYPT_BLOCKS / 2); 236 237 for (i = 0; i < BCRYPT_BLOCKS; i++) { 238 ciphertext[4 * i + 3] = cdata[i] & 0xff; 239 cdata[i] = cdata[i] >> 8; 240 ciphertext[4 * i + 2] = cdata[i] & 0xff; 241 cdata[i] = cdata[i] >> 8; 242 ciphertext[4 * i + 1] = cdata[i] & 0xff; 243 cdata[i] = cdata[i] >> 8; 244 ciphertext[4 * i + 0] = cdata[i] & 0xff; 245 } 246 247 248 encrypted[0] = '$'; 249 encrypted[1] = BCRYPT_VERSION; 250 encrypted[2] = '$'; 251 252 snprintf(encrypted + 3, 4, "%2.2u$", logr); 253 254 encode_base64((u_int8_t *) encrypted + 6, csalt, BCRYPT_MAXSALT); 255 encode_base64((u_int8_t *) encrypted + strlen(encrypted), ciphertext, 256 4 * BCRYPT_BLOCKS); 257 return encrypted; 258 } 259 260 static void 261 encode_base64(buffer, data, len) 262 u_int8_t *buffer; 263 u_int8_t *data; 264 u_int16_t len; 265 { 266 u_int8_t *bp = buffer; 267 u_int8_t *p = data; 268 u_int8_t c1, c2; 269 while (p < data + len) { 270 c1 = *p++; 271 *bp++ = Base64Code[(c1 >> 2)]; 272 c1 = (c1 & 0x03) << 4; 273 c2 = *p++; 274 if (p >= data + len) { 275 *bp++ = Base64Code[c1]; 276 break; 277 } 278 c1 |= (c2 >> 4) & 0x0f; 279 *bp++ = Base64Code[c1]; 280 c1 = (c2 & 0x0f) << 2; 281 c2 = *p++; 282 if (p >= data + len) { 283 *bp++ = Base64Code[c1]; 284 break; 285 } 286 c1 |= (c2 >> 6) & 0x03; 287 *bp++ = Base64Code[c1]; 288 *bp++ = Base64Code[c2 & 0x3f]; 289 } 290 *bp = '\0'; 291 } 292 #ifdef TEST 293 void 294 main() 295 { 296 char blubber[73]; 297 char salt[100]; 298 char *p; 299 salt[0] = '$'; 300 salt[1] = BCRYPT_VERSION; 301 salt[2] = '$'; 302 303 snprintf(salt + 3, 4, "%2.2u$", 5); 304 305 printf("24 bytes of salt: "); 306 fgets(salt + 6, 94, stdin); 307 salt[99] = 0; 308 printf("72 bytes of password: "); 309 fpurge(stdin); 310 fgets(blubber, 73, stdin); 311 blubber[72] = 0; 312 313 p = crypt(blubber, salt); 314 printf("Passwd entry: %s\n\n", p); 315 316 p = bcrypt_gensalt(5); 317 printf("Generated salt: %s\n", p); 318 p = crypt(blubber, p); 319 printf("Passwd entry: %s\n", p); 320 } 321 #endif 322