1 /* $NetBSD: bcrypt.c,v 1.3 2003/08/06 08:34:32 jdolecek 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 <sys/cdefs.h> 54 __RCSID("$NetBSD: bcrypt.c,v 1.3 2003/08/06 08:34:32 jdolecek Exp $"); 55 56 #include <stdio.h> 57 #include <stdlib.h> 58 #include <sys/types.h> 59 #include <string.h> 60 #include <pwd.h> 61 62 #include "blowfish.c" 63 64 /* This implementation is adaptable to current computing power. 65 * You can have up to 2^31 rounds which should be enough for some 66 * time to come. 67 */ 68 69 #define BCRYPT_VERSION '2' 70 #define BCRYPT_MAXSALT 16 /* Precomputation is just so nice */ 71 #define BCRYPT_BLOCKS 6 /* Ciphertext blocks */ 72 #define BCRYPT_MINROUNDS 16 /* we have log2(rounds) in salt */ 73 74 static void encode_salt(char *, u_int8_t *, u_int16_t, u_int8_t); 75 static void encode_base64(u_int8_t *, u_int8_t *, u_int16_t); 76 static void decode_base64(u_int8_t *, u_int16_t, u_int8_t *); 77 78 char *__bcrypt(const char *, const char *); /* XXX */ 79 80 static char encrypted[_PASSWORD_LEN]; 81 static char gsalt[BCRYPT_MAXSALT * 4 / 3 + 1]; 82 static char error[] = ":"; 83 84 const static u_int8_t Base64Code[] = 85 "./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"; 86 87 const static u_int8_t index_64[128] = 88 { 89 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 90 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 91 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 92 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 93 255, 255, 255, 255, 255, 255, 0, 1, 54, 55, 94 56, 57, 58, 59, 60, 61, 62, 63, 255, 255, 95 255, 255, 255, 255, 255, 2, 3, 4, 5, 6, 96 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 97 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 98 255, 255, 255, 255, 255, 255, 28, 29, 30, 99 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 100 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 101 51, 52, 53, 255, 255, 255, 255, 255 102 }; 103 #define CHAR64(c) ( (c) > 127 ? 255 : index_64[(c)]) 104 105 static void 106 decode_base64(u_int8_t *buffer, u_int16_t len, u_int8_t *data) 107 { 108 u_int8_t *bp = buffer; 109 u_int8_t *p = data; 110 u_int8_t c1, c2, c3, c4; 111 while (bp < buffer + len) { 112 c1 = CHAR64(*p); 113 c2 = CHAR64(*(p + 1)); 114 115 /* Invalid data */ 116 if (c1 == 255 || c2 == 255) 117 break; 118 119 *bp++ = (c1 << 2) | ((c2 & 0x30) >> 4); 120 if (bp >= buffer + len) 121 break; 122 123 c3 = CHAR64(*(p + 2)); 124 if (c3 == 255) 125 break; 126 127 *bp++ = ((c2 & 0x0f) << 4) | ((c3 & 0x3c) >> 2); 128 if (bp >= buffer + len) 129 break; 130 131 c4 = CHAR64(*(p + 3)); 132 if (c4 == 255) 133 break; 134 *bp++ = ((c3 & 0x03) << 6) | c4; 135 136 p += 4; 137 } 138 } 139 140 static void 141 encode_salt(char *salt, u_int8_t *csalt, u_int16_t clen, u_int8_t logr) 142 { 143 salt[0] = '$'; 144 salt[1] = BCRYPT_VERSION; 145 salt[2] = 'a'; 146 salt[3] = '$'; 147 148 snprintf(salt + 4, 4, "%2.2u$", logr); 149 150 encode_base64((u_int8_t *) salt + 7, csalt, clen); 151 } 152 153 /* Generates a salt for this version of crypt. 154 Since versions may change. Keeping this here 155 seems sensible. 156 */ 157 char * 158 bcrypt_gensalt(u_int8_t log_rounds) 159 { 160 u_int8_t csalt[BCRYPT_MAXSALT]; 161 u_int16_t i; 162 u_int32_t seed = 0; 163 164 for (i = 0; i < BCRYPT_MAXSALT; i++) { 165 if (i % 4 == 0) 166 seed = arc4random(); 167 csalt[i] = seed & 0xff; 168 seed = seed >> 8; 169 } 170 171 if (log_rounds < 4) 172 log_rounds = 4; 173 174 encode_salt(gsalt, csalt, BCRYPT_MAXSALT, log_rounds); 175 return gsalt; 176 } 177 178 /* We handle $Vers$log2(NumRounds)$salt+passwd$ 179 i.e. $2$04$iwouldntknowwhattosayetKdJ6iFtacBqJdKe6aW7ou */ 180 181 char * 182 __bcrypt(key, salt) 183 const char *key; 184 const 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, minor; 190 u_int8_t ciphertext[4 * BCRYPT_BLOCKS] = "OrpheanBeholderScryDoubt"; 191 u_int8_t csalt[BCRYPT_MAXSALT]; 192 u_int32_t cdata[BCRYPT_BLOCKS]; 193 194 /* Discard "$" identifier */ 195 salt++; 196 197 if (*salt > BCRYPT_VERSION) { 198 /* How do I handle errors ? Return ':' */ 199 return error; 200 } 201 202 /* Check for minor versions */ 203 if (salt[1] != '$') { 204 switch (salt[1]) { 205 case 'a': 206 /* 'ab' should not yield the same as 'abab' */ 207 minor = salt[1]; 208 salt++; 209 break; 210 default: 211 return error; 212 } 213 } else 214 minor = 0; 215 216 /* Discard version + "$" identifier */ 217 salt += 2; 218 219 if (salt[2] != '$') 220 /* Out of sync with passwd entry */ 221 return error; 222 223 /* Computer power doesn't increase linear, 2^x should be fine */ 224 if ((rounds = (u_int32_t) 1 << (logr = atoi(salt))) < BCRYPT_MINROUNDS) 225 return error; 226 227 /* Discard num rounds + "$" identifier */ 228 salt += 3; 229 230 if (strlen(salt) * 3 / 4 < BCRYPT_MAXSALT) 231 return error; 232 233 /* We dont want the base64 salt but the raw data */ 234 decode_base64(csalt, BCRYPT_MAXSALT, (u_int8_t *) salt); 235 salt_len = BCRYPT_MAXSALT; 236 key_len = strlen(key) + (minor >= 'a' ? 1 : 0); 237 238 /* Setting up S-Boxes and Subkeys */ 239 Blowfish_initstate(&state); 240 Blowfish_expandstate(&state, csalt, salt_len, 241 (u_int8_t *) key, key_len); 242 for (k = 0; k < rounds; k++) { 243 Blowfish_expand0state(&state, (u_int8_t *) key, key_len); 244 Blowfish_expand0state(&state, csalt, salt_len); 245 } 246 247 /* This can be precomputed later */ 248 j = 0; 249 for (i = 0; i < BCRYPT_BLOCKS; i++) 250 cdata[i] = Blowfish_stream2word(ciphertext, 4 * BCRYPT_BLOCKS, &j); 251 252 /* Now do the encryption */ 253 for (k = 0; k < 64; k++) 254 blf_enc(&state, cdata, BCRYPT_BLOCKS / 2); 255 256 for (i = 0; i < BCRYPT_BLOCKS; i++) { 257 ciphertext[4 * i + 3] = cdata[i] & 0xff; 258 cdata[i] = cdata[i] >> 8; 259 ciphertext[4 * i + 2] = cdata[i] & 0xff; 260 cdata[i] = cdata[i] >> 8; 261 ciphertext[4 * i + 1] = cdata[i] & 0xff; 262 cdata[i] = cdata[i] >> 8; 263 ciphertext[4 * i + 0] = cdata[i] & 0xff; 264 } 265 266 267 i = 0; 268 encrypted[i++] = '$'; 269 encrypted[i++] = BCRYPT_VERSION; 270 if (minor) 271 encrypted[i++] = minor; 272 encrypted[i++] = '$'; 273 274 snprintf(encrypted + i, 4, "%2.2u$", logr); 275 276 encode_base64((u_int8_t *) encrypted + i + 3, csalt, BCRYPT_MAXSALT); 277 encode_base64((u_int8_t *) encrypted + strlen(encrypted), ciphertext, 278 4 * BCRYPT_BLOCKS - 1); 279 return encrypted; 280 } 281 282 static void 283 encode_base64(u_int8_t *buffer, u_int8_t *data, u_int16_t len) 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 if (p >= data + len) { 293 *bp++ = Base64Code[c1]; 294 break; 295 } 296 c2 = *p++; 297 c1 |= (c2 >> 4) & 0x0f; 298 *bp++ = Base64Code[c1]; 299 c1 = (c2 & 0x0f) << 2; 300 if (p >= data + len) { 301 *bp++ = Base64Code[c1]; 302 break; 303 } 304 c2 = *p++; 305 c1 |= (c2 >> 6) & 0x03; 306 *bp++ = Base64Code[c1]; 307 *bp++ = Base64Code[c2 & 0x3f]; 308 } 309 *bp = '\0'; 310 } 311 #if 0 312 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