src/libs/crypt/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
  31 #include <sys/cdefs.h>
  32 __FBSDID("$FreeBSD: src/secure/lib/libcrypt/crypt-blowfish.c,v 1.4 2003/06/02 19:17:24 markm Exp $");
  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 #include <stdio.h>
  54 #include <stdlib.h>
  55 #include <sys/types.h>
  56 #include <string.h>
  57 #include <pwd.h>
  58 #include "blowfish.h"
  59 #include "crypt.h"
  60
  61 /* This implementation is adaptable to current computing power.
  62  * You can have up to 2^31 rounds which should be enough for some
  63  * time to come.
  64  */
  65
  66 #define BCRYPT_VERSION '2'
  67 #define BCRYPT_MAXSALT 16       /* Precomputation is just so nice */
  68 #define BCRYPT_BLOCKS 6         /* Ciphertext blocks */
  69 #define BCRYPT_MINROUNDS 16     /* we have log2(rounds) in salt */
  70
  71 static void encode_base64(u_int8_t *, u_int8_t *, u_int16_t);
  72 static void decode_base64(u_int8_t *, u_int16_t, const u_int8_t *);
  73
  74 static char    encrypted[_PASSWORD_LEN];
  75 static char    error[] = ":";
  76
  77 static const u_int8_t Base64Code[] =
  78 "./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
  79
  80 static const u_int8_t index_64[128] =
  81 {
  82         255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
  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, 0, 1, 54, 55,
  87         56, 57, 58, 59, 60, 61, 62, 63, 255, 255,
  88         255, 255, 255, 255, 255, 2, 3, 4, 5, 6,
  89         7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
  90         17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27,
  91         255, 255, 255, 255, 255, 255, 28, 29, 30,
  92         31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
  93         41, 42, 43, 44, 45, 46, 47, 48, 49, 50,
  94         51, 52, 53, 255, 255, 255, 255, 255
  95 };
  96 #define CHAR64(c)  ( (c) > 127 ? 255 : index_64[(c)])
  97
  98 static void
  99 decode_base64(u_int8_t *buffer, u_int16_t len, const u_int8_t *data)
 100 {
 101         u_int8_t *bp = buffer;
 102         const u_int8_t *p = data;
 103         u_int8_t c1, c2, c3, c4;
 104         while (bp < buffer + len) {
 105                 c1 = CHAR64(*p);
 106                 c2 = CHAR64(*(p + 1));
 107
 108                 /* Invalid data */
 109                 if (c1 == 255 || c2 == 255)
 110                         break;
 111
 112                 *bp++ = (u_int8_t)((c1 << 2) | ((c2 & 0x30) >> 4));
 113                 if (bp >= buffer + len)
 114                         break;
 115
 116                 c3 = CHAR64(*(p + 2));
 117                 if (c3 == 255)
 118                         break;
 119
 120                 *bp++ = ((c2 & 0x0f) << 4) | ((c3 & 0x3c) >> 2);
 121                 if (bp >= buffer + len)
 122                         break;
 123
 124                 c4 = CHAR64(*(p + 3));
 125                 if (c4 == 255)
 126                         break;
 127                 *bp++ = ((c3 & 0x03) << 6) | c4;
 128
 129                 p += 4;
 130         }
 131 }
 132
 133 /* We handle $Vers$log2(NumRounds)$salt+passwd$
 134    i.e. $2$04$iwouldntknowwhattosayetKdJ6iFtacBqJdKe6aW7ou */
 135
 136 char   *
 137 crypt_blowfish(const char *key, const char *salt)
 138 {
 139         blf_ctx state;
 140         u_int32_t rounds, i, k;
 141         u_int16_t j;
 142         u_int8_t key_len, salt_len, logr, minr;
 143         u_int8_t ciphertext[4 * BCRYPT_BLOCKS] = "OrpheanBeholderScryDoubt";
 144         u_int8_t csalt[BCRYPT_MAXSALT];
 145         u_int32_t cdata[BCRYPT_BLOCKS];
 146         static const char     *magic = "$2a$04$";
 147
 148                 /* Defaults */
 149         minr = 'a';
 150         logr = 4;
 151         rounds = 1 << logr;
 152
 153         /* If it starts with the magic string, then skip that */
 154         if(!strncmp(salt, magic, strlen(magic))) {
 155                 salt += strlen(magic);
 156         }
 157         else if (*salt == '$') {
 158
 159                 /* Discard "$" identifier */
 160                 salt++;
 161
 162                 if (*salt > BCRYPT_VERSION) {
 163                         /* How do I handle errors ? Return ':' */
 164                         return error;
 165                 }
 166
 167                 /* Check for minor versions */
 168                 if (salt[1] != '$') {
 169                          switch (salt[1]) {
 170                          case 'a':
 171                                  /* 'ab' should not yield the same as 'abab' */
 172                                  minr = (u_int8_t)salt[1];
 173                                  salt++;
 174                                  break;
 175                          default:
 176                                  return error;
 177                          }
 178                 } else
 179                          minr = 0;
 180
 181                 /* Discard version + "$" identifier */
 182                 salt += 2;
 183
 184                 if (salt[2] != '$')
 185                         /* Out of sync with passwd entry */
 186                         return error;
 187
 188                 /* Computer power doesnt increase linear, 2^x should be fine */
 189                 logr = (u_int8_t)atoi(salt);
 190                 rounds = 1 << logr;
 191                 if (rounds < BCRYPT_MINROUNDS)
 192                         return error;
 193
 194                 /* Discard num rounds + "$" identifier */
 195                 salt += 3;
 196         }
 197
 198
 199         /* We dont want the base64 salt but the raw data */
 200         decode_base64(csalt, BCRYPT_MAXSALT, (const u_int8_t *)salt);
 201         salt_len = BCRYPT_MAXSALT;
 202         key_len = (u_int8_t)(strlen(key) + (minr >= 'a' ? 1 : 0));
 203
 204         /* Setting up S-Boxes and Subkeys */
 205         Blowfish_initstate(&state);
 206         Blowfish_expandstate(&state, csalt, salt_len,
 207             (const u_int8_t *) key, key_len);
 208         for (k = 0; k < rounds; k++) {
 209                 Blowfish_expand0state(&state, (const u_int8_t *) key, key_len);
 210                 Blowfish_expand0state(&state, csalt, salt_len);
 211         }
 212
 213         /* This can be precomputed later */
 214         j = 0;
 215         for (i = 0; i < BCRYPT_BLOCKS; i++)
 216                 cdata[i] = Blowfish_stream2word(ciphertext, 4 * BCRYPT_BLOCKS, &j);
 217
 218         /* Now do the encryption */
 219         for (k = 0; k < 64; k++)
 220                 blf_enc(&state, cdata, BCRYPT_BLOCKS / 2);
 221
 222         for (i = 0; i < BCRYPT_BLOCKS; i++) {
 223                 ciphertext[4 * i + 3] = cdata[i] & 0xff;
 224                 cdata[i] = cdata[i] >> 8;
 225                 ciphertext[4 * i + 2] = cdata[i] & 0xff;
 226                 cdata[i] = cdata[i] >> 8;
 227                 ciphertext[4 * i + 1] = cdata[i] & 0xff;
 228                 cdata[i] = cdata[i] >> 8;
 229                 ciphertext[4 * i + 0] = cdata[i] & 0xff;
 230         }
 231
 232
 233         i = 0;
 234         encrypted[i++] = '$';
 235         encrypted[i++] = BCRYPT_VERSION;
 236         if (minr)
 237                 encrypted[i++] = (int8_t)minr;
 238         encrypted[i++] = '$';
 239
 240         snprintf(encrypted + i, 4, "%2.2u$", logr);
 241
 242         encode_base64((u_int8_t *) encrypted + i + 3, csalt, BCRYPT_MAXSALT);
 243         encode_base64((u_int8_t *) encrypted + strlen(encrypted), ciphertext,
 244             4 * BCRYPT_BLOCKS - 1);
 245         return encrypted;
 246 }
 247
 248 static void
 249 encode_base64(u_int8_t *buffer, u_int8_t *data, u_int16_t len)
 250 {
 251         u_int8_t *bp = buffer;
 252         u_int8_t *p = data;
 253         u_int8_t c1, c2;
 254         while (p < data + len) {
 255                 c1 = *p++;
 256                 *bp++ = Base64Code[(c1 >> 2)];
 257                 c1 = (c1 & 0x03) << 4;
 258                 if (p >= data + len) {
 259                         *bp++ = Base64Code[c1];
 260                         break;
 261                 }
 262                 c2 = *p++;
 263                 c1 |= (c2 >> 4) & 0x0f;
 264                 *bp++ = Base64Code[c1];
 265                 c1 = (c2 & 0x0f) << 2;
 266                 if (p >= data + len) {
 267                         *bp++ = Base64Code[c1];
 268                         break;
 269                 }
 270                 c2 = *p++;
 271                 c1 |= (c2 >> 6) & 0x03;
 272                 *bp++ = Base64Code[c1];
 273                 *bp++ = Base64Code[c2 & 0x3f];
 274         }
 275         *bp = '\0';
 276 }
 277
 278 #if 0
 279 void
 280 main()
 281 {
 282         char    blubber[73];
 283         char    salt[100];
 284         char   *p;
 285         salt[0] = '$';
 286         salt[1] = BCRYPT_VERSION;
 287         salt[2] = '$';
 288
 289         snprintf(salt + 3, 4, "%2.2u$", 5);
 290
 291         printf("24 bytes of salt: ");
 292         fgets(salt + 6, 94, stdin);
 293         salt[99] = 0;
 294         printf("72 bytes of password: ");
 295         fpurge(stdin);
 296         fgets(blubber, 73, stdin);
 297         blubber[72] = 0;
 298
 299         p = crypt(blubber, salt);
 300         printf("Passwd entry: %s\n\n", p);
 301
 302         p = bcrypt_gensalt(5);
 303         printf("Generated salt: %s\n", p);
 304         p = crypt(blubber, p);
 305         printf("Passwd entry: %s\n", p);
 306 }
 307 #endif