lib/krb5/str2key.c

   1 /*
   2  * Copyright (c) 1997 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  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  *
  17  * 3. All advertising materials mentioning features or use of this software
  18  *    must display the following acknowledgement:
  19  *      This product includes software developed by Kungliga Tekniska
  20  *      Högskolan and its contributors.
  21  *
  22  * 4. Neither the name of the Institute nor the names of its contributors
  23  *    may be used to endorse or promote products derived from this software
  24  *    without specific prior written permission.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  36  * SUCH DAMAGE.
  37  */
  38
  39 #include <krb5_locl.h>
  40
  41 RCSID("$Id$");
  42
  43 /*
  44  * Reverse 8 bytes
  45  */
  46
  47 static void
  48 reverse (unsigned char *s)
  49 {
  50      static const unsigned char tbl[] = {
  51           0x0,
  52           0x8,
  53           0x4,
  54           0xC,
  55           0x2,
  56           0xA,
  57           0x6,
  58           0xE,
  59           0x1,
  60           0x9,
  61           0x5,
  62           0xD,
  63           0x3,
  64           0xB,
  65           0x7,
  66           0xF
  67      };
  68
  69      char tmp;
  70
  71 #define REVONE(str, i, j) \
  72 do { tmp = str[i]; str[i] = str[j]; str[j] = tmp;} while(0)
  73
  74      REVONE(s,0,7);
  75      REVONE(s,1,6);
  76      REVONE(s,2,5);
  77      REVONE(s,3,4);
  78 #undef REVONE
  79
  80 #define REVTWO(q) \
  81 q = (tbl[q & 0x0F] << 4) | (tbl[q >> 4])
  82
  83      REVTWO(s[0]);
  84      REVTWO(s[1]);
  85      REVTWO(s[2]);
  86      REVTWO(s[3]);
  87      REVTWO(s[4]);
  88      REVTWO(s[5]);
  89      REVTWO(s[6]);
  90      REVTWO(s[7]);
  91
  92 #undef REVTWO
  93 }
  94
  95 /*
  96  * A = A xor B. A & B is 8 bytes.
  97  */
  98
  99 static void
 100 xor (des_cblock *key, unsigned char *b)
 101 {
 102     unsigned char *a = (unsigned char*)key;
 103     a[0] ^= b[0];
 104     a[1] ^= b[1];
 105     a[2] ^= b[2];
 106     a[3] ^= b[3];
 107     a[4] ^= b[4];
 108     a[5] ^= b[5];
 109     a[6] ^= b[6];
 110     a[7] ^= b[7];
 111 }
 112
 113 /*
 114  * Init a from b
 115  */
 116
 117 static void
 118 init (unsigned char *a, unsigned char *b)
 119 {
 120      a[0] = b[0] << 1;
 121      a[1] = b[1] << 1;
 122      a[2] = b[2] << 1;
 123      a[3] = b[3] << 1;
 124      a[4] = b[4] << 1;
 125      a[5] = b[5] << 1;
 126      a[6] = b[6] << 1;
 127      a[7] = b[7] << 1;
 128 }
 129
 130 static void
 131 DES_string_to_key(const unsigned char *str, size_t len, des_cblock *key)
 132 {
 133     int odd, i;
 134     des_key_schedule sched;
 135
 136     memset (key, 0, sizeof(des_cblock));
 137
 138     odd = 1;
 139     for (i = 0; i < len; i += 8) {
 140         unsigned char tmp[8];
 141
 142         init (tmp, (unsigned char*)&str[i]);
 143
 144         if (odd == 0) {
 145             odd = 1;
 146             reverse (tmp);
 147             init (tmp, tmp);
 148         } else
 149             odd = 0;
 150         xor (key, tmp);
 151     }
 152     des_set_odd_parity (key);
 153     des_set_key (key, sched);
 154     des_cbc_cksum ((des_cblock *)str, key, len, sched, key);
 155     des_set_odd_parity (key);
 156     if (des_is_weak_key (key))
 157         xor (key, (unsigned char*)"\0\0\0\0\0\0\0\xf0");
 158 }
 159
 160 static int
 161 gcd(int a, int b)
 162 {
 163     do{
 164         int r = a % b;
 165         a = b;
 166         b = r;
 167     }while(b);
 168     return a;
 169 }
 170
 171
 172 static void
 173 rr13(unsigned char *buf, size_t len)
 174 {
 175     unsigned char *tmp = malloc(len);
 176     int i;
 177     for(i = 0; i < len; i++){
 178         int x = (buf[i] << 8) | buf[(i + 1) % len];
 179         x >>= 5;
 180         tmp[(i + 2) % len] = x & 0xff;
 181     }
 182     memcpy(buf, tmp, len);
 183     free(tmp);
 184 }
 185
 186 static void
 187 add1(unsigned char *a, unsigned char *b, size_t len)
 188 {
 189     int i;
 190     int carry = 0;
 191     for(i = len - 1; i >= 0; i--){
 192         int x = a[i] + b[i];
 193         carry = x > 0xff;
 194         a[i] = x & 0xff;
 195     }
 196     for(i = len - 1; carry && i >= 0; i--){
 197         int x = a[i] + carry;
 198         carry = x > 0xff;
 199         a[i] = carry & 0xff;
 200     }
 201 }
 202
 203 static void
 204 fold(const unsigned char *str, size_t len, unsigned char *out)
 205 {
 206     const int size = 24;
 207     unsigned char key[24];
 208     int num = 0;
 209     int i;
 210     int lcm = size * len / gcd(size, len);
 211     unsigned char *tmp = malloc(lcm);
 212     unsigned char *buf = malloc(len);
 213     memcpy(buf, str, len);
 214     for(; num < lcm; num += len){
 215         memcpy(tmp + num, buf, len);
 216         rr13(buf, len);
 217     }
 218     free(buf);
 219     memset(key, 0, sizeof(key));
 220     for(i = 0; i < lcm; i += size)
 221         add1(key, tmp + i, size);
 222
 223     memcpy(out, key, size);
 224 }
 225
 226 static void
 227 DES3_string_to_key(const unsigned char *str, size_t len, des_cblock *keys)
 228 {
 229     unsigned char tmp[24];
 230     des_cblock ivec;
 231     des_key_schedule s[3];
 232     int i;
 233
 234     fold(str, len, tmp);
 235     for(i = 0; i < 3; i++){
 236         memcpy(keys + i, tmp + 8 * i, 8);
 237         des_set_odd_parity(keys + i);
 238         if(des_is_weak_key(keys + i))
 239             xor(keys + i, (unsigned char*)"\0\0\0\0\0\0\0\xf0");
 240         des_set_key(keys + i, s[i]);
 241     }
 242     memset(&ivec, 0, sizeof(ivec));
 243     des_ede3_cbc_encrypt((void*)tmp, (void*)tmp, sizeof(tmp),
 244                          s[0], s[1], s[2], &ivec, 1);
 245     memset(s, 0, sizeof(s));
 246     for(i = 0; i < 3; i++){
 247         memcpy(keys + i, tmp + 8 * i, 8);
 248         des_set_odd_parity(keys + i);
 249         if(des_is_weak_key(keys + i))
 250             xor(keys + i, (unsigned char*)"\0\0\0\0\0\0\0\xf0");
 251     }
 252     memset(tmp, 0, sizeof(tmp));
 253 }
 254
 255
 256 static krb5_error_code
 257 string_to_key_internal (const unsigned char *str,
 258                         size_t str_len,
 259                         krb5_data *salt,
 260                         krb5_keytype ktype,
 261                         krb5_keyblock *key)
 262 {
 263      size_t len;
 264      unsigned char *s, *p;
 265      krb5_error_code ret;
 266
 267      len = str_len + salt->length;
 268 #if 1
 269      len = (len + 7) / 8 * 8;
 270 #endif
 271      p = s = malloc (len);
 272      if (p == NULL)
 273           return ENOMEM;
 274      memset (s, 0, len);
 275      strncpy ((char *)p, (char *)str, str_len);
 276      p += str_len;
 277      memcpy (p, salt->data, salt->length);
 278
 279      switch(ktype){
 280      case KEYTYPE_DES:{
 281          des_cblock tmpkey;
 282          DES_string_to_key(s, len, &tmpkey);
 283          ret = krb5_data_copy(&key->keyvalue, tmpkey, sizeof(des_cblock));
 284          memset(&tmpkey, 0, sizeof(tmpkey));
 285          break;
 286      }
 287      case KEYTYPE_DES3:{
 288          des_cblock keys[3];
 289          DES3_string_to_key(s, len, keys);
 290          ret = krb5_data_copy(&key->keyvalue, keys, sizeof(keys));
 291          memset(keys, 0, sizeof(keys));
 292          break;
 293      }
 294      default:
 295          ret = KRB5_PROG_KEYTYPE_NOSUPP;
 296          break;
 297      }
 298      memset(s, 0, len);
 299      free(s);
 300      if(ret)
 301          return ret;
 302      key->keytype = ktype;
 303      return 0;
 304 }
 305
 306 krb5_error_code
 307 krb5_string_to_key (const char *str,
 308                     krb5_data *salt,
 309                     krb5_keytype ktype,
 310                     krb5_keyblock *key)
 311 {
 312     return string_to_key_internal ((const unsigned char *)str,
 313                                    strlen(str), salt, ktype, key);
 314 }
 315
 316 krb5_error_code
 317 krb5_string_to_key_data (krb5_data *str,
 318                          krb5_data *salt,
 319                          krb5_keytype ktype,
 320                          krb5_keyblock *key)
 321 {
 322     return string_to_key_internal (str->data, str->length, salt, ktype, key);
 323 }
 324
 325 krb5_error_code
 326 krb5_get_salt (krb5_principal princ,
 327                krb5_data *salt)
 328 {
 329     size_t len;
 330     int i;
 331     krb5_error_code err;
 332     char *p;
 333
 334     len = strlen(princ->realm);
 335     for (i = 0; i < princ->name.name_string.len; ++i)
 336         len += strlen(princ->name.name_string.val[i]);
 337     err = krb5_data_alloc (salt, len);
 338     if (err)
 339         return err;
 340     p = salt->data;
 341     strncpy (p, princ->realm, strlen(princ->realm));
 342     p += strlen(princ->realm);
 343     for (i = 0; i < princ->name.name_string.len; ++i) {
 344         strncpy (p,
 345                  princ->name.name_string.val[i],
 346                  strlen(princ->name.name_string.val[i]));
 347         p += strlen(princ->name.name_string.val[i]);
 348     }
 349     return 0;
 350 }
 351