Files
heimdal/lib/krb5/str2key.c
Johan Danielsson 7a8eeccb69 Fix DES3 string-to-key.
git-svn-id: svn://svn.h5l.se/heimdal/trunk/heimdal@4705 ec53bebd-3082-4978-b11e-865c3cabbd6b
1998-04-03 04:03:39 +00:00

463 lines
12 KiB
C

/*
* Copyright (c) 1997, 1998 Kungliga Tekniska Högskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Kungliga Tekniska
* Högskolan and its contributors.
*
* 4. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <krb5_locl.h>
RCSID("$Id$");
/*
* Reverse 8 bytes
*/
static void
reverse (unsigned char *s)
{
static const unsigned char tbl[] = {
0x0,
0x8,
0x4,
0xC,
0x2,
0xA,
0x6,
0xE,
0x1,
0x9,
0x5,
0xD,
0x3,
0xB,
0x7,
0xF
};
char tmp;
#define REVONE(str, i, j) \
do { tmp = str[i]; str[i] = str[j]; str[j] = tmp;} while(0)
REVONE(s,0,7);
REVONE(s,1,6);
REVONE(s,2,5);
REVONE(s,3,4);
#undef REVONE
#define REVTWO(q) \
q = (tbl[q & 0x0F] << 4) | (tbl[q >> 4])
REVTWO(s[0]);
REVTWO(s[1]);
REVTWO(s[2]);
REVTWO(s[3]);
REVTWO(s[4]);
REVTWO(s[5]);
REVTWO(s[6]);
REVTWO(s[7]);
#undef REVTWO
}
/*
* A = A xor B. A & B is 8 bytes.
*/
static void
xor (des_cblock *key, const unsigned char *b)
{
unsigned char *a = (unsigned char*)key;
a[0] ^= b[0];
a[1] ^= b[1];
a[2] ^= b[2];
a[3] ^= b[3];
a[4] ^= b[4];
a[5] ^= b[5];
a[6] ^= b[6];
a[7] ^= b[7];
}
/*
* Init a from b
*/
static void
init (unsigned char *a, const unsigned char *b)
{
a[0] = b[0] << 1;
a[1] = b[1] << 1;
a[2] = b[2] << 1;
a[3] = b[3] << 1;
a[4] = b[4] << 1;
a[5] = b[5] << 1;
a[6] = b[6] << 1;
a[7] = b[7] << 1;
}
static void
DES_string_to_key(const char *str, size_t len, des_cblock *key)
{
/* could use des_string_to_key here, but then `str' must be zero
terminated, and the final weak-key check has to be added */
int even, i;
des_key_schedule sched;
memset (key, 0, sizeof(des_cblock));
even = 0;
for (i = 0; i < len; i += 8) {
unsigned char tmp[8];
init (tmp, (const unsigned char*)(str + i));
if (even) {
reverse (tmp);
init (tmp, tmp);
}
even = !even;
xor (key, tmp);
}
des_set_odd_parity (key);
des_set_key (key, sched);
des_cbc_cksum ((des_cblock *)str, key, len, sched, key);
des_set_odd_parity (key);
if (des_is_weak_key (key))
xor (key, (unsigned char*)"\0\0\0\0\0\0\0\xf0");
}
static void
rr13(unsigned char *buf, size_t len)
{
int i;
/* assert(len >= 3); */
unsigned a = buf[0], b = buf[len-1];
#define F(A, B) ((((A) << 3) | ((B) >> 5)) & 0xff)
buf[0] = F(buf[len-2], buf[len-1]);
for(i = len - 3; i >= 1; i--)
buf[i + 2] = F(buf[i], buf[i+1]);
buf[2] = F(a, buf[1]);
buf[1] = F(b, a);
#undef F
}
/* Add `b' to `a', both beeing one's complement numbers. */
static void
add1(unsigned char *a, unsigned char *b, size_t len)
{
int i;
int carry = 0;
for(i = len - 1; i >= 0; i--){
int x = a[i] + b[i] + carry;
carry = x > 0xff;
a[i] = x & 0xff;
}
for(i = len - 1; carry && i >= 0; i--){
int x = a[i] + carry;
carry = x > 0xff;
a[i] = carry & 0xff;
}
}
/* key should point to a buffer of at least size (24) bytes */
static void
fold(const unsigned char *str, size_t len, unsigned char *key)
{
const int size = 24;
/* if len < size we need at most N * len bytes, ie < 2 * size;
if len > size we need at most 2 * len */
size_t maxlen = 2 * max(size, len);
size_t l = 0;
unsigned char *tmp = malloc(maxlen);
unsigned char *buf = malloc(len);
memcpy(buf, str, len);
memset(key, 0, size);
do {
memcpy(tmp + l, buf, len);
l += len;
rr13(buf, len);
while(l >= size) {
add1(key, tmp, size);
l -= size;
if(l == 0)
break;
memmove(tmp, tmp + size, l);
}
} while(l != 0);
memset(buf, 0, len);
free(buf);
memset(tmp, 0, maxlen);
free(tmp);
}
static void
DES3_string_to_key(const unsigned char *str, size_t len, des_cblock *keys)
{
unsigned char tmp[24];
des_cblock ivec;
des_key_schedule s[3];
int i;
fold(str, len, tmp);
for(i = 0; i < 3; i++){
memcpy(keys + i, tmp + 8 * i, 8);
des_set_odd_parity(keys + i);
if(des_is_weak_key(keys + i))
xor(keys + i, (unsigned char*)"\0\0\0\0\0\0\0\xf0");
des_set_key(keys + i, s[i]);
}
memset(&ivec, 0, sizeof(ivec));
des_ede3_cbc_encrypt((void*)tmp, (void*)tmp, sizeof(tmp),
s[0], s[1], s[2], &ivec, 1);
memset(s, 0, sizeof(s));
for(i = 0; i < 3; i++){
memcpy(keys + i, tmp + 8 * i, 8);
des_set_odd_parity(keys + i);
if(des_is_weak_key(keys + i))
xor(keys + i, (unsigned char*)"\0\0\0\0\0\0\0\xf0");
}
memset(tmp, 0, sizeof(tmp));
}
/* This defines the Andrew string_to_key function. It accepts a password
* string as input and converts its via a one-way encryption algorithm to a DES
* encryption key. It is compatible with the original Andrew authentication
* service password database.
*/
/*
* Short passwords, i.e 8 characters or less.
*/
static void
afs_cmu_StringToKey (const char *pw, size_t pw_len,
const char *cell, size_t cell_len,
des_cblock *key)
{
char password[8+1]; /* crypt is limited to 8 chars anyway */
int i;
memset (password, 0, sizeof(password));
if(cell_len > 8) cell_len = 8;
strncpy (password, cell, cell_len);
if(pw_len > 8) pw_len = 8;
for (i=0; i < pw_len; i++)
password[i] ^= pw[i];
for (i=0; i<8; i++)
if (password[i] == '\0') password[i] = 'X';
/* crypt only considers the first 8 characters of password but for some
reason returns eleven characters of result (plus the two salt chars). */
strncpy((char *)key, (char *)crypt(password, "#~") + 2, sizeof(des_cblock));
/* parity is inserted into the LSB so leftshift each byte up one bit. This
allows ascii characters with a zero MSB to retain as much significance
as possible. */
{ char *keybytes = (char *)key;
unsigned int temp;
for (i = 0; i < 8; i++) {
temp = (unsigned int) keybytes[i];
keybytes[i] = (unsigned char) (temp << 1);
}
}
des_fixup_key_parity (key);
}
/*
* Long passwords, i.e 9 characters or more.
*/
static void
afs_transarc_StringToKey (const char *pw, size_t pw_len,
const char *cell, size_t cell_len,
des_cblock *key)
{
des_key_schedule schedule;
des_cblock temp_key;
des_cblock ivec;
char password[512];
size_t passlen;
memcpy(password, pw, min(pw_len, sizeof(password)));
if(pw_len < sizeof(password))
memcpy(password + pw_len, cell, min(cell_len,
sizeof(password) - pw_len));
passlen = min(sizeof(password), pw_len + cell_len);
memcpy(&ivec, "kerberos", 8);
memcpy(&temp_key, "kerberos", 8);
des_fixup_key_parity (&temp_key);
des_key_sched (&temp_key, schedule);
des_cbc_cksum ((des_cblock *)password, &ivec, passlen, schedule, &ivec);
memcpy(&temp_key, &ivec, 8);
des_fixup_key_parity (&temp_key);
des_key_sched (&temp_key, schedule);
des_cbc_cksum ((des_cblock *)password, key, passlen, schedule, &ivec);
memset(&schedule, 0, sizeof(schedule));
memset(&temp_key, 0, sizeof(temp_key));
memset(&ivec, 0, sizeof(ivec));
memset(password, 0, sizeof(password));
des_fixup_key_parity (key);
}
static void
AFS3_string_to_key(const char *pw, size_t pw_len,
const char *cell, size_t cell_len,
des_cblock *key)
{
if(pw_len > 8)
afs_transarc_StringToKey (pw, pw_len, cell, cell_len, key);
else
afs_cmu_StringToKey (pw, pw_len, cell, cell_len, key);
}
static void *
get_str(const void *pw, size_t pw_len, const void *salt, size_t salt_len,
size_t *ret_len)
{
char *p;
size_t len = pw_len + salt_len;
len = (len + 7) & ~7;
p = calloc(len, 1);
if(p == NULL)
return NULL;
memcpy(p, pw, pw_len);
memcpy(p + pw_len, salt, salt_len);
*ret_len = len;
return p;
}
static krb5_error_code
string_to_key_internal (const unsigned char *str,
size_t str_len,
krb5_data *salt,
krb5_keytype ktype,
krb5_keyblock *key)
{
size_t len;
unsigned char *s = NULL;
krb5_error_code ret;
switch(ktype & KEYTYPE_KEYTYPE_MASK){
case KEYTYPE_DES:{
des_cblock tmpkey;
if(ktype & KEYTYPE_USE_AFS3_SALT)
AFS3_string_to_key(str, str_len, salt->data, salt->length, &tmpkey);
else{
s = get_str(str, str_len, salt->data, salt->length, &len);
if(s == NULL)
return ENOMEM;
DES_string_to_key(s, len, &tmpkey);
}
ret = krb5_data_copy(&key->keyvalue, tmpkey, sizeof(des_cblock));
memset(&tmpkey, 0, sizeof(tmpkey));
break;
}
case KEYTYPE_DES3:{
des_cblock keys[3];
s = get_str(str, str_len, salt->data, salt->length, &len);
if(s == NULL)
return ENOMEM;
/* only des should pad to 8 */
DES3_string_to_key(s, str_len + salt->length, keys);
ret = krb5_data_copy(&key->keyvalue, keys, sizeof(keys));
memset(keys, 0, sizeof(keys));
break;
}
default:
ret = KRB5_PROG_KEYTYPE_NOSUPP;
break;
}
if(s){
memset(s, 0, len);
free(s);
}
if(ret)
return ret;
key->keytype = ktype & KEYTYPE_KEYTYPE_MASK;
return 0;
}
krb5_error_code
krb5_string_to_key (const char *str,
krb5_data *salt,
krb5_keytype ktype,
krb5_keyblock *key)
{
return string_to_key_internal ((const unsigned char *)str,
strlen(str), salt, ktype, key);
}
krb5_error_code
krb5_string_to_key_data (krb5_data *str,
krb5_data *salt,
krb5_keytype ktype,
krb5_keyblock *key)
{
return string_to_key_internal (str->data, str->length, salt, ktype, key);
}
krb5_error_code
krb5_get_salt (krb5_principal princ,
krb5_data *salt)
{
size_t len;
int i;
krb5_error_code err;
char *p;
len = strlen(princ->realm);
for (i = 0; i < princ->name.name_string.len; ++i)
len += strlen(princ->name.name_string.val[i]);
err = krb5_data_alloc (salt, len);
if (err)
return err;
p = salt->data;
strncpy (p, princ->realm, strlen(princ->realm));
p += strlen(princ->realm);
for (i = 0; i < princ->name.name_string.len; ++i) {
strncpy (p,
princ->name.name_string.val[i],
strlen(princ->name.name_string.val[i]));
p += strlen(princ->name.name_string.val[i]);
}
return 0;
}