1 /* $OpenBSD: bcrypt.c,v 1.1 1997/02/13 16:31:16 provos Exp $ */ 2 /* 3 * Copyright 1997 Niels Provos <provos@physnet.uni-hamburg.de> 4 * 5 * Modification and redistribution in source and binary forms is 6 * permitted provided that due credit is given to the author and the 7 * OpenBSD project (for instance by leaving this copyright notice 8 * intact). 9 */ 10 11 /* This password hashing algorithm was designed by David Mazieres 12 * <dm@lcs.mit.edu> and works as follows: 13 * 14 * 1. state := InitState () 15 * 2. state := ExpandKey (state, salt, password) 3. 16 * REPEAT rounds: 17 * state := ExpandKey (state, 0, salt) 18 * state := ExpandKey(state, 0, password) 19 * 4. ctext := "OpenBSDbcrypthashfunc" 20 * 5. REPEAT 64: 21 * ctext := Encrypt_ECB (state, ctext); 22 * 6. RETURN Concatenate (salt, ctext); 23 * 24 */ 25 26 #ifdef TEST 27 #include <stdio.h> 28 #endif 29 30 #include <stdlib.h> 31 #include <time.h> 32 #include <sys/types.h> 33 #include <string.h> 34 #include <pwd.h> 35 #include <blf.h> 36 37 /* This implementation is adaptable to current computing power. 38 * You can have up to 2^31 rounds which should be enough for some 39 * time to come. 40 */ 41 42 #define BCRYPT_VERSION '2' 43 #define BCRYPT_MAXSALT 16 /* Precomputation is just so nice */ 44 #define BCRYPT_BLOCKS 6 /* Ciphertext blocks */ 45 #define BCRYPT_MINROUNDS 16 /* we have log2(rounds) in salt */ 46 47 char *bcrypt_gensalt __P((u_int8_t)); 48 49 static void encode_salt __P((char *, u_int8_t *, u_int16_t, u_int8_t)); 50 static void encode_base64 __P((u_int8_t *, u_int8_t *, u_int16_t)); 51 static void decode_base64 __P((u_int8_t *, u_int16_t, u_int8_t *)); 52 53 static char encrypted[_PASSWORD_LEN]; 54 static char gsalt[BCRYPT_MAXSALT * 4 / 3 + 1]; 55 static char error[] = ":"; 56 57 const static u_int8_t Base64Code[] = 58 "./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"; 59 60 const static u_int8_t index_64[128] = 61 { 62 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 63 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 64 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 65 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 66 255, 255, 255, 255, 255, 255, 0, 1, 54, 55, 67 56, 57, 58, 59, 60, 61, 62, 63, 255, 255, 68 255, 255, 255, 255, 255, 2, 3, 4, 5, 6, 69 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 70 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 71 255, 255, 255, 255, 255, 255, 28, 29, 30, 72 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 73 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 74 51, 52, 53, 255, 255, 255, 255, 255 75 }; 76 #define CHAR64(c) ( (c) > 127 ? 255 : index_64[(c)]) 77 78 static void 79 decode_base64(buffer, len, data) 80 u_int8_t *buffer; 81 u_int16_t len; 82 u_int8_t *data; 83 { 84 u_int8_t *bp = buffer; 85 u_int8_t *p = data; 86 u_int8_t c1, c2, c3, c4; 87 while (bp < buffer + len) { 88 c1 = CHAR64(*p); 89 c2 = CHAR64(*(p + 1)); 90 91 /* Invalid data */ 92 if (c1 == 255 || c2 == 255) 93 break; 94 95 *bp++ = (c1 << 2) | ((c2 & 0x30) >> 4); 96 if (bp >= buffer + len) 97 break; 98 99 c3 = CHAR64(*(p + 2)); 100 if (c3 == 255) 101 break; 102 103 *bp++ = ((c2 & 0x0f) << 4) | ((c3 & 0x3c) >> 2); 104 if (bp >= buffer + len) 105 break; 106 107 c4 = CHAR64(*(p + 3)); 108 if (c4 == 255) 109 break; 110 *bp++ = ((c3 & 0x03) << 6) | c4; 111 112 p += 4; 113 } 114 } 115 116 static void 117 encode_salt(salt, csalt, clen, logr) 118 char *salt; 119 u_int8_t *csalt; 120 u_int16_t clen; 121 u_int8_t logr; 122 { 123 salt[0] = '$'; 124 salt[1] = BCRYPT_VERSION; 125 salt[2] = '$'; 126 127 snprintf(salt + 3, 4, "%2.2u$", logr); 128 129 encode_base64((u_int8_t *) salt + 6, csalt, clen); 130 } 131 /* Generates a salt for this version of crypt. 132 Since versions may change. Keeping this here 133 seems sensible. 134 */ 135 136 char * 137 bcrypt_gensalt(log_rounds) 138 u_int8_t log_rounds; 139 { 140 u_int8_t csalt[BCRYPT_MAXSALT]; 141 u_int16_t i; 142 u_int32_t seed = 0; 143 (void) srandom((int) time((time_t *) NULL)); 144 for (i = 0; i < BCRYPT_MAXSALT; i++) { 145 if (i % 4 == 0) 146 seed = random(); 147 csalt[i] = seed & 0xff; 148 seed = seed >> 8; 149 } 150 151 if (log_rounds < 4) 152 log_rounds = 4; 153 154 encode_salt(gsalt, csalt, BCRYPT_MAXSALT, log_rounds); 155 return gsalt; 156 } 157 /* We handle $Vers$log2(NumRounds)$salt+passwd$ 158 i.e. $2$04$iwouldntknowwhattosayetKdJ6iFtacBqJdKe6aW7ou */ 159 160 char * 161 bcrypt(key, salt) 162 char *key; 163 char *salt; 164 { 165 blf_ctx state; 166 u_int32_t rounds, i, k; 167 u_int16_t j; 168 u_int8_t key_len, salt_len, logr; 169 u_int8_t ciphertext[4 * BCRYPT_BLOCKS] = "OpenBSDbcrypthashfunc"; 170 u_int8_t csalt[BCRYPT_MAXSALT]; 171 u_int32_t cdata[BCRYPT_BLOCKS]; 172 /* Discard "$" identifier */ 173 salt++; 174 175 if (*salt > BCRYPT_VERSION) { 176 /* How do I handle errors ? Return ':' */ 177 return error; 178 } 179 /* Discard version + "$" identifier */ 180 salt += 2; 181 182 if (*(salt + 2) != '$') 183 /* Out of sync with passwd entry */ 184 return error; 185 186 /* Computer power doesnt increase linear, 2^x should be fine */ 187 if ((rounds = (u_int32_t) 1 << (logr = atoi(salt))) < BCRYPT_MINROUNDS) 188 return error; 189 190 /* Discard num rounds + "$" identifier */ 191 salt += 3; 192 193 /* We dont want the base64 salt but the raw data */ 194 decode_base64(csalt, BCRYPT_MAXSALT, (u_int8_t *) salt); 195 salt_len = BCRYPT_MAXSALT; 196 key_len = strlen(key); 197 198 /* Setting up S-Boxes and Subkeys */ 199 Blowfish_initstate(&state); 200 Blowfish_expandstate(&state, csalt, salt_len, 201 (u_int8_t *) key, key_len); 202 for (k = 0; k < rounds; k++) { 203 Blowfish_expand0state(&state, (u_int8_t *) key, key_len); 204 Blowfish_expand0state(&state, csalt, salt_len); 205 } 206 207 /* This can be precomputed later */ 208 j = 0; 209 for (i = 0; i < BCRYPT_BLOCKS; i++) 210 cdata[i] = Blowfish_stream2word(ciphertext, 4 * BCRYPT_BLOCKS, &j); 211 212 /* Now do the encryption */ 213 for (k = 0; k < 64; k++) 214 blf_enc(&state, cdata, BCRYPT_BLOCKS / 2); 215 216 for (i = 0; i < BCRYPT_BLOCKS; i++) { 217 ciphertext[4 * i + 3] = cdata[i] & 0xff; 218 cdata[i] = cdata[i] >> 8; 219 ciphertext[4 * i + 2] = cdata[i] & 0xff; 220 cdata[i] = cdata[i] >> 8; 221 ciphertext[4 * i + 1] = cdata[i] & 0xff; 222 cdata[i] = cdata[i] >> 8; 223 ciphertext[4 * i + 0] = cdata[i] & 0xff; 224 } 225 226 227 encrypted[0] = '$'; 228 encrypted[1] = BCRYPT_VERSION; 229 encrypted[2] = '$'; 230 231 snprintf(encrypted + 3, 4, "%2.2u$", logr); 232 233 encode_base64((u_int8_t *) encrypted + 6, csalt, BCRYPT_MAXSALT); 234 encode_base64((u_int8_t *) encrypted + strlen(encrypted), ciphertext, 235 4 * BCRYPT_BLOCKS); 236 return encrypted; 237 } 238 239 static void 240 encode_base64(buffer, data, len) 241 u_int8_t *buffer; 242 u_int8_t *data; 243 u_int16_t len; 244 { 245 u_int8_t *bp = buffer; 246 u_int8_t *p = data; 247 u_int8_t c1, c2; 248 while (p < data + len) { 249 c1 = *p++; 250 *bp++ = Base64Code[(c1 >> 2)]; 251 c1 = (c1 & 0x03) << 4; 252 c2 = *p++; 253 if (p >= data + len) { 254 *bp++ = Base64Code[c1]; 255 break; 256 } 257 c1 |= (c2 >> 4) & 0x0f; 258 *bp++ = Base64Code[c1]; 259 c1 = (c2 & 0x0f) << 2; 260 c2 = *p++; 261 if (p >= data + len) { 262 *bp++ = Base64Code[c1]; 263 break; 264 } 265 c1 |= (c2 >> 6) & 0x03; 266 *bp++ = Base64Code[c1]; 267 *bp++ = Base64Code[c2 & 0x3f]; 268 } 269 *bp = '\0'; 270 } 271 #ifdef TEST 272 void 273 main() 274 { 275 char blubber[73]; 276 char salt[100]; 277 char *p; 278 salt[0] = '$'; 279 salt[1] = BCRYPT_VERSION; 280 salt[2] = '$'; 281 282 snprintf(salt + 3, 4, "%2.2u$", 5); 283 284 printf("24 bytes of salt: "); 285 fgets(salt + 6, 94, stdin); 286 salt[99] = 0; 287 printf("72 bytes of password: "); 288 fpurge(stdin); 289 fgets(blubber, 73, stdin); 290 blubber[72] = 0; 291 292 p = crypt(blubber, salt); 293 printf("Passwd entry: %s\n\n", p); 294 295 p = bcrypt_gensalt(5); 296 printf("Generated salt: %s\n", p); 297 p = crypt(blubber, p); 298 printf("Passwd entry: %s\n", p); 299 } 300 #endif 301