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/*
* authusekey - decode a key from ascii and use it
*/
#include <stdio.h>
#include <ctype.h>
#include "ntp_types.h"
#include "ntp_string.h"
#include "ntp_stdlib.h"
/*
* Types of ascii representations for keys. "Standard" means a 64 bit
* hex number in NBS format, i.e. with the low order bit of each byte
* a parity bit. "NTP" means a 64 bit key in NTP format, with the
* high order bit of each byte a parity bit. "Ascii" means a 1-to-8
* character string whose ascii representation is used as the key.
*/
#ifdef DES
#define KEY_TYPE_STD 1
#define KEY_TYPE_NTP 2
#define KEY_TYPE_ASCII 3
#define STD_PARITY_BITS 0x01010101
#endif
#ifdef MD5
#define KEY_TYPE_MD5 4
#endif
int
authusekey(keyno, keytype, str)
u_long keyno;
int keytype;
const char *str;
{
U_LONG key[2];
u_char keybytes[8];
const char *cp;
char *xdigit;
int len;
int i;
static char *hex = "0123456789abcdef";
cp = str;
len = strlen(cp);
if (len == 0)
return 0;
switch(keytype) {
#ifdef DES
case KEY_TYPE_STD:
case KEY_TYPE_NTP:
if (len != 16) /* Lazy. Should define constant */
return 0;
/*
* Decode hex key.
*/
key[0] = 0;
key[1] = 0;
for (i = 0; i < 16; i++) {
if (!isascii(*cp))
return 0;
xdigit = strchr(hex, isupper(*cp) ? tolower(*cp) : *cp);
cp++;
if (xdigit == 0)
return 0;
key[i>>3] <<= 4;
key[i>>3] |= (U_LONG)(xdigit - hex) & 0xf;
}
/*
* If this is an NTP format key, put it into NBS format
*/
if (keytype == KEY_TYPE_NTP) {
for (i = 0; i < 2; i++)
key[i] = ((key[i] << 1) & ~STD_PARITY_BITS)
| ((key[i] >> 7) & STD_PARITY_BITS);
}
/*
* Check the parity, reject the key if the check fails
*/
if (!DESauth_parity(key)) {
return 0;
}
/*
* We can't find a good reason not to use this key.
* So use it.
*/
DESauth_setkey(keyno, key);
break;
case KEY_TYPE_ASCII:
/*
* Make up key from ascii representation
*/
memset((char *) keybytes, 0, sizeof(keybytes));
for (i = 0; i < 8 && i < len; i++)
keybytes[i] = *cp++ << 1;
key[0] = (U_LONG)keybytes[0] << 24 | (U_LONG)keybytes[1] << 16
| (U_LONG)keybytes[2] << 8 | (U_LONG)keybytes[3];
key[1] = (U_LONG)keybytes[4] << 24 | (U_LONG)keybytes[5] << 16
| (U_LONG)keybytes[6] << 8 | (U_LONG)keybytes[7];
/*
* Set parity on key
*/
(void)DESauth_parity(key);
/*
* Now set key in.
*/
DESauth_setkey(keyno, key);
break;
#endif
#ifdef MD5
case KEY_TYPE_MD5:
/* XXX FIXME: MD5auth_setkey() casts arg2 back to (char *) */
MD5auth_setkey(keyno, (U_LONG *)str);
break;
#endif
default:
/* Oh, well */
return 0;
}
return 1;
}
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