crypt-blowfish.c revision 74106
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 * $FreeBSD: head/secure/lib/libcrypt/crypt-blowfish.c 74106 2001-03-11 16:05:43Z markm $ 31 */ 32 33/* This password hashing algorithm was designed by David Mazieres 34 * <dm@lcs.mit.edu> and works as follows: 35 * 36 * 1. state := InitState () 37 * 2. state := ExpandKey (state, salt, password) 3. 38 * REPEAT rounds: 39 * state := ExpandKey (state, 0, salt) 40 * state := ExpandKey(state, 0, password) 41 * 4. ctext := "OrpheanBeholderScryDoubt" 42 * 5. REPEAT 64: 43 * ctext := Encrypt_ECB (state, ctext); 44 * 6. RETURN Concatenate (salt, ctext); 45 * 46 */ 47 48/* 49 * FreeBSD implementation by Paul Herman <pherman@frenchfries.net> 50 */ 51 52#if 0 53#include <stdio.h> 54#endif 55 56#include <stdio.h> 57#include <stdlib.h> 58#include <sys/types.h> 59#include <string.h> 60#include <pwd.h> 61#include "blowfish.h" 62 63/* This implementation is adaptable to current computing power. 64 * You can have up to 2^31 rounds which should be enough for some 65 * time to come. 66 */ 67 68#define BCRYPT_VERSION '2' 69#define BCRYPT_MAXSALT 16 /* Precomputation is just so nice */ 70#define BCRYPT_BLOCKS 6 /* Ciphertext blocks */ 71#define BCRYPT_MINROUNDS 16 /* we have log2(rounds) in salt */ 72 73char *bcrypt_gensalt __P((u_int8_t)); 74 75static void encode_salt __P((char *, u_int8_t *, u_int16_t, u_int8_t)); 76static void encode_base64 __P((u_int8_t *, u_int8_t *, u_int16_t)); 77static void decode_base64 __P((u_int8_t *, u_int16_t, u_int8_t *)); 78 79static char encrypted[_PASSWORD_LEN]; 80static char gsalt[BCRYPT_MAXSALT * 4 / 3 + 1]; 81static char error[] = ":"; 82 83const static u_int8_t Base64Code[] = 84"./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"; 85 86const static u_int8_t index_64[128] = 87{ 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, 255, 255, 255, 255, 91 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 92 255, 255, 255, 255, 255, 255, 0, 1, 54, 55, 93 56, 57, 58, 59, 60, 61, 62, 63, 255, 255, 94 255, 255, 255, 255, 255, 2, 3, 4, 5, 6, 95 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 96 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 97 255, 255, 255, 255, 255, 255, 28, 29, 30, 98 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 99 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 100 51, 52, 53, 255, 255, 255, 255, 255 101}; 102#define CHAR64(c) ( (c) > 127 ? 255 : index_64[(c)]) 103 104#ifdef __STDC__ 105static void 106decode_base64(u_int8_t *buffer, u_int16_t len, u_int8_t *data) 107#else 108static void 109decode_base64(buffer, len, data) 110 u_int8_t *buffer; 111 u_int16_t len; 112 u_int8_t *data; 113#endif 114{ 115 u_int8_t *bp = buffer; 116 u_int8_t *p = data; 117 u_int8_t c1, c2, c3, c4; 118 while (bp < buffer + len) { 119 c1 = CHAR64(*p); 120 c2 = CHAR64(*(p + 1)); 121 122 /* Invalid data */ 123 if (c1 == 255 || c2 == 255) 124 break; 125 126 *bp++ = (c1 << 2) | ((c2 & 0x30) >> 4); 127 if (bp >= buffer + len) 128 break; 129 130 c3 = CHAR64(*(p + 2)); 131 if (c3 == 255) 132 break; 133 134 *bp++ = ((c2 & 0x0f) << 4) | ((c3 & 0x3c) >> 2); 135 if (bp >= buffer + len) 136 break; 137 138 c4 = CHAR64(*(p + 3)); 139 if (c4 == 255) 140 break; 141 *bp++ = ((c3 & 0x03) << 6) | c4; 142 143 p += 4; 144 } 145} 146 147#ifdef __STDC__ 148static void 149encode_salt(char *salt, u_int8_t *csalt, u_int16_t clen, u_int8_t logr) 150#else 151static void 152encode_salt(salt, csalt, clen, logr) 153 char *salt; 154 u_int8_t *csalt; 155 u_int16_t clen; 156 u_int8_t logr; 157#endif 158{ 159 salt[0] = '$'; 160 salt[1] = BCRYPT_VERSION; 161 salt[2] = 'a'; 162 salt[3] = '$'; 163 164 snprintf(salt + 4, 4, "%2.2u$", logr); 165 166 encode_base64((u_int8_t *) salt + 7, csalt, clen); 167} 168/* Generates a salt for this version of crypt. 169 Since versions may change. Keeping this here 170 seems sensible. 171 */ 172 173#ifdef __STDC__ 174char * 175bcrypt_gensalt(u_int8_t log_rounds) 176#else 177char * 178bcrypt_gensalt(log_rounds) 179 u_int8_t log_rounds; 180#endif 181{ 182 u_int8_t csalt[BCRYPT_MAXSALT]; 183 u_int16_t i; 184 u_int32_t seed = 0; 185 186 for (i = 0; i < BCRYPT_MAXSALT; i++) { 187 if (i % 4 == 0) 188 seed = arc4random(); 189 csalt[i] = seed & 0xff; 190 seed = seed >> 8; 191 } 192 193 if (log_rounds < 4) 194 log_rounds = 4; 195 196 encode_salt(gsalt, csalt, BCRYPT_MAXSALT, log_rounds); 197 return gsalt; 198} 199/* We handle $Vers$log2(NumRounds)$salt+passwd$ 200 i.e. $2$04$iwouldntknowwhattosayetKdJ6iFtacBqJdKe6aW7ou */ 201 202char * 203crypt_blowfish(key, salt) 204 const char *key; 205 const char *salt; 206{ 207 blf_ctx state; 208 u_int32_t rounds, i, k; 209 u_int16_t j; 210 u_int8_t key_len, salt_len, logr, minor; 211 u_int8_t ciphertext[4 * BCRYPT_BLOCKS] = "OrpheanBeholderScryDoubt"; 212 u_int8_t csalt[BCRYPT_MAXSALT]; 213 u_int32_t cdata[BCRYPT_BLOCKS]; 214 static char *magic = "$2a$04$"; 215 216 /* Defaults */ 217 minor = 'a'; 218 logr = 4; 219 rounds = 1 << logr; 220 221 /* If it starts with the magic string, then skip that */ 222 if(!strncmp(salt, magic, strlen(magic))) { 223 salt += strlen(magic); 224 } 225 else if (*salt == '$') { 226 227 /* Discard "$" identifier */ 228 salt++; 229 230 if (*salt > BCRYPT_VERSION) { 231 /* How do I handle errors ? Return ':' */ 232 return error; 233 } 234 235 /* Check for minor versions */ 236 if (salt[1] != '$') { 237 switch (salt[1]) { 238 case 'a': 239 /* 'ab' should not yield the same as 'abab' */ 240 minor = salt[1]; 241 salt++; 242 break; 243 default: 244 return error; 245 } 246 } else 247 minor = 0; 248 249 /* Discard version + "$" identifier */ 250 salt += 2; 251 252 if (salt[2] != '$') 253 /* Out of sync with passwd entry */ 254 return error; 255 256 /* Computer power doesnt increase linear, 2^x should be fine */ 257 if ((rounds = (u_int32_t) 1 << (logr = atoi(salt))) < BCRYPT_MINROUNDS) 258 return error; 259 260 /* Discard num rounds + "$" identifier */ 261 salt += 3; 262 } 263 264 265 /* We dont want the base64 salt but the raw data */ 266 decode_base64(csalt, BCRYPT_MAXSALT, (u_int8_t *) salt); 267 salt_len = BCRYPT_MAXSALT; 268 key_len = strlen(key) + (minor >= 'a' ? 1 : 0); 269 270 /* Setting up S-Boxes and Subkeys */ 271 Blowfish_initstate(&state); 272 Blowfish_expandstate(&state, csalt, salt_len, 273 (u_int8_t *) key, key_len); 274 for (k = 0; k < rounds; k++) { 275 Blowfish_expand0state(&state, (u_int8_t *) key, key_len); 276 Blowfish_expand0state(&state, csalt, salt_len); 277 } 278 279 /* This can be precomputed later */ 280 j = 0; 281 for (i = 0; i < BCRYPT_BLOCKS; i++) 282 cdata[i] = Blowfish_stream2word(ciphertext, 4 * BCRYPT_BLOCKS, &j); 283 284 /* Now do the encryption */ 285 for (k = 0; k < 64; k++) 286 blf_enc(&state, cdata, BCRYPT_BLOCKS / 2); 287 288 for (i = 0; i < BCRYPT_BLOCKS; i++) { 289 ciphertext[4 * i + 3] = cdata[i] & 0xff; 290 cdata[i] = cdata[i] >> 8; 291 ciphertext[4 * i + 2] = cdata[i] & 0xff; 292 cdata[i] = cdata[i] >> 8; 293 ciphertext[4 * i + 1] = cdata[i] & 0xff; 294 cdata[i] = cdata[i] >> 8; 295 ciphertext[4 * i + 0] = cdata[i] & 0xff; 296 } 297 298 299 i = 0; 300 encrypted[i++] = '$'; 301 encrypted[i++] = BCRYPT_VERSION; 302 if (minor) 303 encrypted[i++] = minor; 304 encrypted[i++] = '$'; 305 306 snprintf(encrypted + i, 4, "%2.2u$", logr); 307 308 encode_base64((u_int8_t *) encrypted + i + 3, csalt, BCRYPT_MAXSALT); 309 encode_base64((u_int8_t *) encrypted + strlen(encrypted), ciphertext, 310 4 * BCRYPT_BLOCKS - 1); 311 return encrypted; 312} 313 314#ifdef __STDC__ 315static void 316encode_base64(u_int8_t *buffer, u_int8_t *data, u_int16_t len) 317#else 318static void 319encode_base64(buffer, data, len) 320 u_int8_t *buffer; 321 u_int8_t *data; 322 u_int16_t len; 323#endif 324{ 325 u_int8_t *bp = buffer; 326 u_int8_t *p = data; 327 u_int8_t c1, c2; 328 while (p < data + len) { 329 c1 = *p++; 330 *bp++ = Base64Code[(c1 >> 2)]; 331 c1 = (c1 & 0x03) << 4; 332 if (p >= data + len) { 333 *bp++ = Base64Code[c1]; 334 break; 335 } 336 c2 = *p++; 337 c1 |= (c2 >> 4) & 0x0f; 338 *bp++ = Base64Code[c1]; 339 c1 = (c2 & 0x0f) << 2; 340 if (p >= data + len) { 341 *bp++ = Base64Code[c1]; 342 break; 343 } 344 c2 = *p++; 345 c1 |= (c2 >> 6) & 0x03; 346 *bp++ = Base64Code[c1]; 347 *bp++ = Base64Code[c2 & 0x3f]; 348 } 349 *bp = '\0'; 350} 351#if 0 352void 353main() 354{ 355 char blubber[73]; 356 char salt[100]; 357 char *p; 358 salt[0] = '$'; 359 salt[1] = BCRYPT_VERSION; 360 salt[2] = '$'; 361 362 snprintf(salt + 3, 4, "%2.2u$", 5); 363 364 printf("24 bytes of salt: "); 365 fgets(salt + 6, 94, stdin); 366 salt[99] = 0; 367 printf("72 bytes of password: "); 368 fpurge(stdin); 369 fgets(blubber, 73, stdin); 370 blubber[72] = 0; 371 372 p = crypt(blubber, salt); 373 printf("Passwd entry: %s\n\n", p); 374 375 p = bcrypt_gensalt(5); 376 printf("Generated salt: %s\n", p); 377 p = crypt(blubber, p); 378 printf("Passwd entry: %s\n", p); 379} 380#endif 381