lib/krb5/salt-des.c

   1 /*
   2  * Copyright (c) 1997 - 2008 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. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include "krb5_locl.h"
  35
  36 #ifdef HEIM_WEAK_CRYPTO
  37
  38 #ifdef ENABLE_AFS_STRING_TO_KEY
  39
  40 /* This defines the Andrew string_to_key function.  It accepts a password
  41  * string as input and converts it via a one-way encryption algorithm to a DES
  42  * encryption key.  It is compatible with the original Andrew authentication
  43  * service password database.
  44  */
  45
  46 /*
  47  * Short passwords, i.e 8 characters or less.
  48  */
  49 static void
  50 krb5_DES_AFS3_CMU_string_to_key (krb5_data pw,
  51                                  krb5_data cell,
  52                                  DES_cblock *key)
  53 {
  54     char  password[8+1];        /* crypt is limited to 8 chars anyway */
  55     size_t   i;
  56
  57     for(i = 0; i < 8; i++) {
  58         char c = ((i < pw.length) ? ((char*)pw.data)[i] : 0) ^
  59             ((i < cell.length) ?
  60              tolower(((unsigned char*)cell.data)[i]) : 0);
  61         password[i] = c ? c : 'X';
  62     }
  63     password[8] = '\0';
  64
  65     memcpy(key, crypt(password, "p1") + 2, sizeof(DES_cblock));
  66
  67     /* parity is inserted into the LSB so left shift each byte up one
  68        bit. This allows ascii characters with a zero MSB to retain as
  69        much significance as possible. */
  70     for (i = 0; i < sizeof(DES_cblock); i++)
  71         ((unsigned char*)key)[i] <<= 1;
  72     DES_set_odd_parity (key);
  73 }
  74
  75 /*
  76  * Long passwords, i.e 9 characters or more.
  77  */
  78 static void
  79 krb5_DES_AFS3_Transarc_string_to_key (krb5_data pw,
  80                                       krb5_data cell,
  81                                       DES_cblock *key)
  82 {
  83     DES_key_schedule schedule;
  84     DES_cblock temp_key;
  85     DES_cblock ivec;
  86     char password[512];
  87     size_t passlen;
  88
  89     memcpy(password, pw.data, min(pw.length, sizeof(password)));
  90     if(pw.length < sizeof(password)) {
  91         int len = min(cell.length, sizeof(password) - pw.length);
  92         size_t i;
  93
  94         memcpy(password + pw.length, cell.data, len);
  95         for (i = pw.length; i < pw.length + len; ++i)
  96             password[i] = tolower((unsigned char)password[i]);
  97     }
  98     passlen = min(sizeof(password), pw.length + cell.length);
  99     memcpy(&ivec, "kerberos", 8);
 100     memcpy(&temp_key, "kerberos", 8);
 101     DES_set_odd_parity (&temp_key);
 102     DES_set_key_unchecked (&temp_key, &schedule);
 103     DES_cbc_cksum ((void*)password, &ivec, passlen, &schedule, &ivec);
 104
 105     memcpy(&temp_key, &ivec, 8);
 106     DES_set_odd_parity (&temp_key);
 107     DES_set_key_unchecked (&temp_key, &schedule);
 108     DES_cbc_cksum ((void*)password, key, passlen, &schedule, &ivec);
 109     memset(&schedule, 0, sizeof(schedule));
 110     memset(&temp_key, 0, sizeof(temp_key));
 111     memset(&ivec, 0, sizeof(ivec));
 112     memset(password, 0, sizeof(password));
 113
 114     DES_set_odd_parity (key);
 115 }
 116
 117 static krb5_error_code
 118 DES_AFS3_string_to_key(krb5_context context,
 119                        krb5_enctype enctype,
 120                        krb5_data password,
 121                        krb5_salt salt,
 122                        krb5_data opaque,
 123                        krb5_keyblock *key)
 124 {
 125     DES_cblock tmp;
 126     if(password.length > 8)
 127         krb5_DES_AFS3_Transarc_string_to_key(password, salt.saltvalue, &tmp);
 128     else
 129         krb5_DES_AFS3_CMU_string_to_key(password, salt.saltvalue, &tmp);
 130     key->keytype = enctype;
 131     krb5_data_copy(&key->keyvalue, tmp, sizeof(tmp));
 132     memset(&key, 0, sizeof(key));
 133     return 0;
 134 }
 135 #endif /* ENABLE_AFS_STRING_TO_KEY */
 136
 137 static void
 138 DES_string_to_key_int(unsigned char *data, size_t length, DES_cblock *key)
 139 {
 140     DES_key_schedule schedule;
 141     size_t i;
 142     int reverse = 0;
 143     unsigned char *p;
 144
 145     unsigned char swap[] = { 0x0, 0x8, 0x4, 0xc, 0x2, 0xa, 0x6, 0xe,
 146                              0x1, 0x9, 0x5, 0xd, 0x3, 0xb, 0x7, 0xf };
 147     memset(key, 0, 8);
 148
 149     p = (unsigned char*)key;
 150     for (i = 0; i < length; i++) {
 151         unsigned char tmp = data[i];
 152         if (!reverse)
 153             *p++ ^= (tmp << 1);
 154         else
 155             *--p ^= (swap[tmp & 0xf] << 4) | swap[(tmp & 0xf0) >> 4];
 156         if((i % 8) == 7)
 157             reverse = !reverse;
 158     }
 159     DES_set_odd_parity(key);
 160     if(DES_is_weak_key(key))
 161         (*key)[7] ^= 0xF0;
 162     DES_set_key_unchecked(key, &schedule);
 163     DES_cbc_cksum((void*)data, key, length, &schedule, key);
 164     memset(&schedule, 0, sizeof(schedule));
 165     DES_set_odd_parity(key);
 166     if(DES_is_weak_key(key))
 167         (*key)[7] ^= 0xF0;
 168 }
 169
 170 static krb5_error_code
 171 krb5_DES_string_to_key(krb5_context context,
 172                        krb5_enctype enctype,
 173                        krb5_data password,
 174                        krb5_salt salt,
 175                        krb5_data opaque,
 176                        krb5_keyblock *key)
 177 {
 178     unsigned char *s;
 179     size_t len;
 180     DES_cblock tmp;
 181
 182 #ifdef ENABLE_AFS_STRING_TO_KEY
 183     if (opaque.length == 1) {
 184         unsigned long v;
 185         _krb5_get_int(opaque.data, &v, 1);
 186         if (v == 1)
 187             return DES_AFS3_string_to_key(context, enctype, password,
 188                                           salt, opaque, key);
 189     }
 190 #endif
 191
 192     len = password.length + salt.saltvalue.length;
 193     s = malloc(len);
 194     if (len > 0 && s == NULL)
 195         return krb5_enomem(context);
 196     memcpy(s, password.data, password.length);
 197     memcpy(s + password.length, salt.saltvalue.data, salt.saltvalue.length);
 198     DES_string_to_key_int(s, len, &tmp);
 199     key->keytype = enctype;
 200     krb5_data_copy(&key->keyvalue, tmp, sizeof(tmp));
 201     memset(&tmp, 0, sizeof(tmp));
 202     memset(s, 0, len);
 203     free(s);
 204     return 0;
 205 }
 206
 207 struct salt_type _krb5_des_salt[] = {
 208     {
 209         KRB5_PW_SALT,
 210         "pw-salt",
 211         krb5_DES_string_to_key
 212     },
 213 #ifdef ENABLE_AFS_STRING_TO_KEY
 214     {
 215         KRB5_AFS3_SALT,
 216         "afs3-salt",
 217         DES_AFS3_string_to_key
 218     },
 219 #endif
 220     { 0, NULL, NULL }
 221 };
 222 #endif