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      1 /*	$NetBSD: salt-des.c,v 1.4 2023/06/19 21:41:44 christos Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1997 - 2008 Kungliga Tekniska Hgskolan
      5  * (Royal Institute of Technology, Stockholm, Sweden).
      6  * All rights reserved.
      7  *
      8  * Redistribution and use in source and binary forms, with or without
      9  * modification, are permitted provided that the following conditions
     10  * are met:
     11  *
     12  * 1. Redistributions of source code must retain the above copyright
     13  *    notice, this list of conditions and the following disclaimer.
     14  *
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * 3. Neither the name of the Institute nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #include "krb5_locl.h"
     37 
     38 #ifdef HEIM_WEAK_CRYPTO
     39 
     40 #ifdef ENABLE_AFS_STRING_TO_KEY
     41 
     42 /* This defines the Andrew string_to_key function.  It accepts a password
     43  * string as input and converts it via a one-way encryption algorithm to a DES
     44  * encryption key.  It is compatible with the original Andrew authentication
     45  * service password database.
     46  */
     47 
     48 /*
     49  * Short passwords, i.e 8 characters or less.
     50  */
     51 static void
     52 krb5_DES_AFS3_CMU_string_to_key (krb5_data pw,
     53 				 krb5_data cell,
     54 				 DES_cblock *key)
     55 {
     56     char  password[8+1];	/* crypt is limited to 8 chars anyway */
     57     size_t   i;
     58 
     59     for(i = 0; i < 8; i++) {
     60 	char c = ((i < pw.length) ? ((char*)pw.data)[i] : 0) ^
     61 	    ((i < cell.length) ?
     62 	     tolower(((unsigned char*)cell.data)[i]) : 0);
     63 	password[i] = c ? c : 'X';
     64     }
     65     password[8] = '\0';
     66 
     67     memcpy(key, crypt(password, "p1") + 2, sizeof(DES_cblock));
     68 
     69     /* parity is inserted into the LSB so left shift each byte up one
     70        bit. This allows ascii characters with a zero MSB to retain as
     71        much significance as possible. */
     72     for (i = 0; i < sizeof(DES_cblock); i++)
     73 	((unsigned char*)key)[i] <<= 1;
     74     DES_set_odd_parity (key);
     75 }
     76 
     77 /*
     78  * Long passwords, i.e 9 characters or more.
     79  */
     80 static void
     81 krb5_DES_AFS3_Transarc_string_to_key (krb5_data pw,
     82 				      krb5_data cell,
     83 				      DES_cblock *key)
     84 {
     85     DES_key_schedule schedule;
     86     DES_cblock temp_key;
     87     DES_cblock ivec;
     88     char password[512];
     89     size_t passlen;
     90 
     91     memcpy(password, pw.data, min(pw.length, sizeof(password)));
     92     if(pw.length < sizeof(password)) {
     93 	int len = min(cell.length, sizeof(password) - pw.length);
     94 	size_t i;
     95 
     96 	memcpy(password + pw.length, cell.data, len);
     97 	for (i = pw.length; i < pw.length + len; ++i)
     98 	    password[i] = tolower((unsigned char)password[i]);
     99     }
    100     passlen = min(sizeof(password), pw.length + cell.length);
    101     memcpy(&ivec, "kerberos", 8);
    102     memcpy(&temp_key, "kerberos", 8);
    103     DES_set_odd_parity (&temp_key);
    104     DES_set_key_unchecked (&temp_key, &schedule);
    105     DES_cbc_cksum ((void*)password, &ivec, passlen, &schedule, &ivec);
    106 
    107     memcpy(&temp_key, &ivec, 8);
    108     DES_set_odd_parity (&temp_key);
    109     DES_set_key_unchecked (&temp_key, &schedule);
    110     DES_cbc_cksum ((void*)password, key, passlen, &schedule, &ivec);
    111     memset(&schedule, 0, sizeof(schedule));
    112     memset(&temp_key, 0, sizeof(temp_key));
    113     memset(&ivec, 0, sizeof(ivec));
    114     memset_s(password, sizeof(password), 0, sizeof(password));
    115 
    116     DES_set_odd_parity (key);
    117 }
    118 
    119 static krb5_error_code
    120 DES_AFS3_string_to_key(krb5_context context,
    121 		       krb5_enctype enctype,
    122 		       krb5_data password,
    123 		       krb5_salt salt,
    124 		       krb5_data opaque,
    125 		       krb5_keyblock *key)
    126 {
    127     DES_cblock tmp;
    128     if(password.length > 8)
    129 	krb5_DES_AFS3_Transarc_string_to_key(password, salt.saltvalue, &tmp);
    130     else
    131 	krb5_DES_AFS3_CMU_string_to_key(password, salt.saltvalue, &tmp);
    132     key->keytype = enctype;
    133     krb5_data_copy(&key->keyvalue, tmp, sizeof(tmp));
    134     memset(&key, 0, sizeof(key));
    135     return 0;
    136 }
    137 #endif /* ENABLE_AFS_STRING_TO_KEY */
    138 
    139 static void
    140 DES_string_to_key_int(unsigned char *data, size_t length, DES_cblock *key)
    141 {
    142     DES_key_schedule schedule;
    143     size_t i;
    144     int reverse = 0;
    145     unsigned char *p;
    146 
    147     unsigned char swap[] = { 0x0, 0x8, 0x4, 0xc, 0x2, 0xa, 0x6, 0xe,
    148 			     0x1, 0x9, 0x5, 0xd, 0x3, 0xb, 0x7, 0xf };
    149     memset(key, 0, 8);
    150 
    151     p = (unsigned char*)key;
    152     for (i = 0; i < length; i++) {
    153 	unsigned char tmp = data[i];
    154 	if (!reverse)
    155 	    *p++ ^= (tmp << 1);
    156 	else
    157 	    *--p ^= (swap[tmp & 0xf] << 4) | swap[(tmp & 0xf0) >> 4];
    158 	if((i % 8) == 7)
    159 	    reverse = !reverse;
    160     }
    161     DES_set_odd_parity(key);
    162     if(DES_is_weak_key(key))
    163 	(*key)[7] ^= 0xF0;
    164     DES_set_key_unchecked(key, &schedule);
    165     DES_cbc_cksum((void*)data, key, length, &schedule, key);
    166     memset(&schedule, 0, sizeof(schedule));
    167     DES_set_odd_parity(key);
    168     if(DES_is_weak_key(key))
    169 	(*key)[7] ^= 0xF0;
    170 }
    171 
    172 static krb5_error_code
    173 krb5_DES_string_to_key(krb5_context context,
    174 		       krb5_enctype enctype,
    175 		       krb5_data password,
    176 		       krb5_salt salt,
    177 		       krb5_data opaque,
    178 		       krb5_keyblock *key)
    179 {
    180     unsigned char *s;
    181     size_t len;
    182     DES_cblock tmp;
    183 
    184 #ifdef ENABLE_AFS_STRING_TO_KEY
    185     if (opaque.length == 1) {
    186 	unsigned long v;
    187 	_krb5_get_int(opaque.data, &v, 1);
    188 	if (v == 1)
    189 	    return DES_AFS3_string_to_key(context, enctype, password,
    190 					  salt, opaque, key);
    191     }
    192 #endif
    193 
    194     len = password.length + salt.saltvalue.length;
    195     s = malloc(len);
    196     if (len > 0 && s == NULL)
    197 	return krb5_enomem(context);
    198     memcpy(s, password.data, password.length);
    199     if (salt.saltvalue.length)
    200         memcpy(s + password.length, salt.saltvalue.data, salt.saltvalue.length);
    201     DES_string_to_key_int(s, len, &tmp);
    202     key->keytype = enctype;
    203     krb5_data_copy(&key->keyvalue, tmp, sizeof(tmp));
    204     memset(&tmp, 0, sizeof(tmp));
    205     memset(s, 0, len);
    206     free(s);
    207     return 0;
    208 }
    209 
    210 struct salt_type _krb5_des_salt[] = {
    211     {
    212 	KRB5_PW_SALT,
    213 	"pw-salt",
    214 	krb5_DES_string_to_key
    215     },
    216 #ifdef ENABLE_AFS_STRING_TO_KEY
    217     {
    218 	KRB5_AFS3_SALT,
    219 	"afs3-salt",
    220 	DES_AFS3_string_to_key
    221     },
    222 #endif
    223     { 0, NULL, NULL }
    224 };
    225 #endif
    226