135 lines
2.6 KiB
C
135 lines
2.6 KiB
C
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/*
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* authusekey - decode a key from ascii and use it
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*/
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#include <stdio.h>
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#include <ctype.h>
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#include "ntp_types.h"
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#include "ntp_string.h"
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#include "ntp_stdlib.h"
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/*
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* Types of ascii representations for keys. "Standard" means a 64 bit
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* hex number in NBS format, i.e. with the low order bit of each byte
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* a parity bit. "NTP" means a 64 bit key in NTP format, with the
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* high order bit of each byte a parity bit. "Ascii" means a 1-to-8
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* character string whose ascii representation is used as the key.
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*/
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#ifdef DES
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#define KEY_TYPE_STD 1
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#define KEY_TYPE_NTP 2
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#define KEY_TYPE_ASCII 3
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#define STD_PARITY_BITS ((unsigned)0x01010101)
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#endif
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#ifdef MD5
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#define KEY_TYPE_MD5 4
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#endif
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int
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authusekey(
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u_long keyno,
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int keytype,
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const u_char *str
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)
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{
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#ifdef DES
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u_int32 key[2];
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u_char keybytes[8];
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char *xdigit;
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int i;
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static const char *hex = "0123456789abcdef";
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#endif
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const u_char *cp;
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int len;
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cp = str;
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len = strlen((const char *)cp);
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if (len == 0)
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return 0;
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switch(keytype) {
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#ifdef DES
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case KEY_TYPE_STD:
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case KEY_TYPE_NTP:
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if (len != 16) /* Lazy. Should define constant */
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return 0;
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/*
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* Decode hex key.
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*/
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key[0] = 0;
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key[1] = 0;
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for (i = 0; i < 16; i++) {
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if (!isascii(*cp))
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return 0;
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xdigit = strchr(hex, isupper(*cp) ? tolower(*cp) : *cp);
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cp++;
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if (xdigit == 0)
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return 0;
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key[i>>3] <<= 4;
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key[i>>3] |= (u_int32)(xdigit - hex) & 0xf;
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}
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/*
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* If this is an NTP format key, put it into NBS format
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*/
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if (keytype == KEY_TYPE_NTP) {
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for (i = 0; i < 2; i++)
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key[i] = ((key[i] << 1) & ~STD_PARITY_BITS)
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| ((key[i] >> 7) & STD_PARITY_BITS);
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}
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/*
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* Check the parity, reject the key if the check fails
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*/
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if (!DESauth_parity(key)) {
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return 0;
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}
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/*
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* We can't find a good reason not to use this key.
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* So use it.
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*/
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DESauth_setkey(keyno, key);
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break;
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case KEY_TYPE_ASCII:
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/*
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* Make up key from ascii representation
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*/
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memset((char *) keybytes, 0, sizeof(keybytes));
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for (i = 0; i < 8 && i < len; i++)
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keybytes[i] = *cp++ << 1;
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key[0] = (u_int32)keybytes[0] << 24 | (u_int32)keybytes[1] << 16
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| (u_int32)keybytes[2] << 8 | (u_int32)keybytes[3];
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key[1] = (u_int32)keybytes[4] << 24 | (u_int32)keybytes[5] << 16
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| (u_int32)keybytes[6] << 8 | (u_int32)keybytes[7];
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/*
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* Set parity on key
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*/
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(void)DESauth_parity(key);
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/*
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* Now set key in.
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*/
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DESauth_setkey(keyno, key);
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break;
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#endif
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#ifdef MD5
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case KEY_TYPE_MD5:
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MD5auth_setkey(keyno, str, (int)strlen((const char *)str));
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break;
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#endif
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default:
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/* Oh, well */
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return 0;
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}
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return 1;
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}
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