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102 lines
2.3 KiB
C
102 lines
2.3 KiB
C
/*
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* Copyright (C) 2004 Mike Wray <mike.wray@hp.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free software Foundation, Inc.,
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* 59 Temple Place, suite 330, Boston, MA 02111-1307 USA
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*
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*/
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#include <linux/config.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/sched.h>
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#include <linux/random.h>
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#include "hash_table.h"
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#define MODULE_NAME "RANDOM"
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#define DEBUG 1
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#undef DEBUG
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#include "debug.h"
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/** @file
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* Source of randomness.
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* Current implementation is not enough.
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* Needs to be cryptographically strong.
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*/
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static unsigned long seed = 0;
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static unsigned long count = 0;
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static unsigned long stir(unsigned long *a, unsigned long b){
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pseudo_des(a, &b);
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return b;
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}
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/** Get one random byte.
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*
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* @return random byte
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*/
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int get_random_byte(void){
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return stir(&seed, ++count);
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}
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#if 0
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/* Get some random bytes.
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*
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* @param dst destination for the bytes
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* @param dst_n number of bytes to get
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*/
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void get_random_bytes(void *dst, int dst_n){
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int i;
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char *p = (char *)dst;
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for(i = 0; i < dst_n; i++){
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*p++ = get_random_byte();
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}
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}
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#endif
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/** Contribute a random byte.
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*
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* @param b byte to contribute
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*/
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void add_random_byte(int b){
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stir(&seed, ++count);
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stir(&seed, b);
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}
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/** Contribute some random bytes.
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*
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* @param src bytes to contribute
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* @param src_n number of bytes
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*/
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void add_random_bytes(const void *src, int src_n){
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int i;
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char *p = (char *)src;
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for(i = 0; i < src_n; i++){
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add_random_byte(*p++);
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}
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}
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int __init random_module_init(void){
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int dummy;
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int tmp = jiffies;
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seed = (unsigned long)&dummy;
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add_random_byte(tmp);
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return 0;
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}
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void __exit random_module_exit(void){
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}
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