secure/lib/libcrypt/crypt-blowfish.c

   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: src/secure/lib/libcrypt/crypt-blowfish.c,v 1.1.2.1 2001/05/24 12:20:03 markm Exp $
  31  * $DragonFly: src/secure/lib/libcrypt/crypt-blowfish.c,v 1.3 2003/11/14 03:54:32 dillon Exp $
  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 /*
  50  * FreeBSD implementation by Paul Herman <pherman@frenchfries.net>
  51  */
  52
  53 #if 0
  54 #include <stdio.h>
  55 #endif
  56
  57 #include <stdio.h>
  58 #include <stdlib.h>
  59 #include <sys/types.h>
  60 #include <string.h>
  61 #include <pwd.h>
  62 #include "blowfish.h"
  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 char   *bcrypt_gensalt (u_int8_t);
  75
  76 static void encode_salt (char *, u_int8_t *, u_int16_t, u_int8_t);
  77 static void encode_base64 (u_int8_t *, u_int8_t *, u_int16_t);
  78 static void decode_base64 (u_int8_t *, u_int16_t, u_int8_t *);
  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 #ifdef __STDC__
 106 static void
 107 decode_base64(u_int8_t *buffer, u_int16_t len, u_int8_t *data)
 108 #else
 109 static void
 110 decode_base64(buffer, len, data)
 111         u_int8_t *buffer;
 112         u_int16_t len;
 113         u_int8_t *data;
 114 #endif
 115 {
 116         u_int8_t *bp = buffer;
 117         u_int8_t *p = data;
 118         u_int8_t c1, c2, c3, c4;
 119         while (bp < buffer + len) {
 120                 c1 = CHAR64(*p);
 121                 c2 = CHAR64(*(p + 1));
 122
 123                 /* Invalid data */
 124                 if (c1 == 255 || c2 == 255)
 125                         break;
 126
 127                 *bp++ = (c1 << 2) | ((c2 & 0x30) >> 4);
 128                 if (bp >= buffer + len)
 129                         break;
 130
 131                 c3 = CHAR64(*(p + 2));
 132                 if (c3 == 255)
 133                         break;
 134
 135                 *bp++ = ((c2 & 0x0f) << 4) | ((c3 & 0x3c) >> 2);
 136                 if (bp >= buffer + len)
 137                         break;
 138
 139                 c4 = CHAR64(*(p + 3));
 140                 if (c4 == 255)
 141                         break;
 142                 *bp++ = ((c3 & 0x03) << 6) | c4;
 143
 144                 p += 4;
 145         }
 146 }
 147
 148 #ifdef __STDC__
 149 static void
 150 encode_salt(char *salt, u_int8_t *csalt, u_int16_t clen, u_int8_t logr)
 151 #else
 152 static void
 153 encode_salt(salt, csalt, clen, logr)
 154         char   *salt;
 155         u_int8_t *csalt;
 156         u_int16_t clen;
 157         u_int8_t logr;
 158 #endif
 159 {
 160         salt[0] = '$';
 161         salt[1] = BCRYPT_VERSION;
 162         salt[2] = 'a';
 163         salt[3] = '$';
 164
 165         snprintf(salt + 4, 4, "%2.2u$", logr);
 166
 167         encode_base64((u_int8_t *) salt + 7, csalt, clen);
 168 }
 169 /* Generates a salt for this version of crypt.
 170    Since versions may change. Keeping this here
 171    seems sensible.
 172  */
 173
 174 #ifdef __STDC__
 175 char *
 176 bcrypt_gensalt(u_int8_t log_rounds)
 177 #else
 178 char *
 179 bcrypt_gensalt(log_rounds)
 180         u_int8_t log_rounds;
 181 #endif
 182 {
 183         u_int8_t csalt[BCRYPT_MAXSALT];
 184         u_int16_t i;
 185         u_int32_t seed = 0;
 186
 187         for (i = 0; i < BCRYPT_MAXSALT; i++) {
 188                 if (i % 4 == 0)
 189                         seed = arc4random();
 190                 csalt[i] = seed & 0xff;
 191                 seed = seed >> 8;
 192         }
 193
 194         if (log_rounds < 4)
 195                 log_rounds = 4;
 196
 197         encode_salt(gsalt, csalt, BCRYPT_MAXSALT, log_rounds);
 198         return gsalt;
 199 }
 200 /* We handle $Vers$log2(NumRounds)$salt+passwd$
 201    i.e. $2$04$iwouldntknowwhattosayetKdJ6iFtacBqJdKe6aW7ou */
 202
 203 char   *
 204 crypt_blowfish(key, salt)
 205         const char   *key;
 206         const char   *salt;
 207 {
 208         blf_ctx state;
 209         u_int32_t rounds, i, k;
 210         u_int16_t j;
 211         u_int8_t key_len, salt_len, logr, minor;
 212         u_int8_t ciphertext[4 * BCRYPT_BLOCKS] = "OrpheanBeholderScryDoubt";
 213         u_int8_t csalt[BCRYPT_MAXSALT];
 214         u_int32_t cdata[BCRYPT_BLOCKS];
 215         static char     *magic = "$2a$04$";
 216
 217                 /* Defaults */
 218         minor = 'a';
 219         logr = 4;
 220         rounds = 1 << logr;
 221
 222         /* If it starts with the magic string, then skip that */
 223         if(!strncmp(salt, magic, strlen(magic))) {
 224                 salt += strlen(magic);
 225         }
 226         else if (*salt == '$') {
 227
 228                 /* Discard "$" identifier */
 229                 salt++;
 230
 231                 if (*salt > BCRYPT_VERSION) {
 232                         /* How do I handle errors ? Return ':' */
 233                         return error;
 234                 }
 235
 236                 /* Check for minor versions */
 237                 if (salt[1] != '$') {
 238                          switch (salt[1]) {
 239                          case 'a':
 240                                  /* 'ab' should not yield the same as 'abab' */
 241                                  minor = salt[1];
 242                                  salt++;
 243                                  break;
 244                          default:
 245                                  return error;
 246                          }
 247                 } else
 248                          minor = 0;
 249
 250                 /* Discard version + "$" identifier */
 251                 salt += 2;
 252
 253                 if (salt[2] != '$')
 254                         /* Out of sync with passwd entry */
 255                         return error;
 256
 257                 /* Computer power doesnt increase linear, 2^x should be fine */
 258                 if ((rounds = (u_int32_t) 1 << (logr = atoi(salt))) < BCRYPT_MINROUNDS)
 259                         return error;
 260
 261                 /* Discard num rounds + "$" identifier */
 262                 salt += 3;
 263         }
 264
 265
 266         /* We dont want the base64 salt but the raw data */
 267         decode_base64(csalt, BCRYPT_MAXSALT, (u_int8_t *) salt);
 268         salt_len = BCRYPT_MAXSALT;
 269         key_len = strlen(key) + (minor >= 'a' ? 1 : 0);
 270
 271         /* Setting up S-Boxes and Subkeys */
 272         Blowfish_initstate(&state);
 273         Blowfish_expandstate(&state, csalt, salt_len,
 274             (u_int8_t *) key, key_len);
 275         for (k = 0; k < rounds; k++) {
 276                 Blowfish_expand0state(&state, (u_int8_t *) key, key_len);
 277                 Blowfish_expand0state(&state, csalt, salt_len);
 278         }
 279
 280         /* This can be precomputed later */
 281         j = 0;
 282         for (i = 0; i < BCRYPT_BLOCKS; i++)
 283                 cdata[i] = Blowfish_stream2word(ciphertext, 4 * BCRYPT_BLOCKS, &j);
 284
 285         /* Now do the encryption */
 286         for (k = 0; k < 64; k++)
 287                 blf_enc(&state, cdata, BCRYPT_BLOCKS / 2);
 288
 289         for (i = 0; i < BCRYPT_BLOCKS; i++) {
 290                 ciphertext[4 * i + 3] = cdata[i] & 0xff;
 291                 cdata[i] = cdata[i] >> 8;
 292                 ciphertext[4 * i + 2] = cdata[i] & 0xff;
 293                 cdata[i] = cdata[i] >> 8;
 294                 ciphertext[4 * i + 1] = cdata[i] & 0xff;
 295                 cdata[i] = cdata[i] >> 8;
 296                 ciphertext[4 * i + 0] = cdata[i] & 0xff;
 297         }
 298
 299
 300         i = 0;
 301         encrypted[i++] = '$';
 302         encrypted[i++] = BCRYPT_VERSION;
 303         if (minor)
 304                 encrypted[i++] = minor;
 305         encrypted[i++] = '$';
 306
 307         snprintf(encrypted + i, 4, "%2.2u$", logr);
 308
 309         encode_base64((u_int8_t *) encrypted + i + 3, csalt, BCRYPT_MAXSALT);
 310         encode_base64((u_int8_t *) encrypted + strlen(encrypted), ciphertext,
 311             4 * BCRYPT_BLOCKS - 1);
 312         return encrypted;
 313 }
 314
 315 #ifdef __STDC__
 316 static void
 317 encode_base64(u_int8_t *buffer, u_int8_t *data, u_int16_t len)
 318 #else
 319 static void
 320 encode_base64(buffer, data, len)
 321         u_int8_t *buffer;
 322         u_int8_t *data;
 323         u_int16_t len;
 324 #endif
 325 {
 326         u_int8_t *bp = buffer;
 327         u_int8_t *p = data;
 328         u_int8_t c1, c2;
 329         while (p < data + len) {
 330                 c1 = *p++;
 331                 *bp++ = Base64Code[(c1 >> 2)];
 332                 c1 = (c1 & 0x03) << 4;
 333                 if (p >= data + len) {
 334                         *bp++ = Base64Code[c1];
 335                         break;
 336                 }
 337                 c2 = *p++;
 338                 c1 |= (c2 >> 4) & 0x0f;
 339                 *bp++ = Base64Code[c1];
 340                 c1 = (c2 & 0x0f) << 2;
 341                 if (p >= data + len) {
 342                         *bp++ = Base64Code[c1];
 343                         break;
 344                 }
 345                 c2 = *p++;
 346                 c1 |= (c2 >> 6) & 0x03;
 347                 *bp++ = Base64Code[c1];
 348                 *bp++ = Base64Code[c2 & 0x3f];
 349         }
 350         *bp = '\0';
 351 }
 352 #if 0
 353 void
 354 main()
 355 {
 356         char    blubber[73];
 357         char    salt[100];
 358         char   *p;
 359         salt[0] = '$';
 360         salt[1] = BCRYPT_VERSION;
 361         salt[2] = '$';
 362
 363         snprintf(salt + 3, 4, "%2.2u$", 5);
 364
 365         printf("24 bytes of salt: ");
 366         fgets(salt + 6, 94, stdin);
 367         salt[99] = 0;
 368         printf("72 bytes of password: ");
 369         fpurge(stdin);
 370         fgets(blubber, 73, stdin);
 371         blubber[72] = 0;
 372
 373         p = crypt(blubber, salt);
 374         printf("Passwd entry: %s\n\n", p);
 375
 376         p = bcrypt_gensalt(5);
 377         printf("Generated salt: %s\n", p);
 378         p = crypt(blubber, p);
 379         printf("Passwd entry: %s\n", p);
 380 }
 381 #endif