134 lines
2.8 KiB
C
134 lines
2.8 KiB
C
/*
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* Copyright (C) 2005-2008 Martin Willi
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* Copyright (C) 2005 Jan Hutter
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* Hochschule fuer Technik Rapperswil
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*
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* This program is free software; you can redistribute it and/or modify it
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* 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. See <http://www.fsf.org/copyleft/gpl.txt>.
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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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#include <string.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <errno.h>
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#include <debug.h>
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#include "random_rng.h"
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#ifndef DEV_RANDOM
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# define DEV_RANDOM "/dev/random"
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#endif
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#ifndef DEV_URANDOM
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# define DEV_URANDOM "/dev/urandom"
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#endif
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typedef struct private_random_rng_t private_random_rng_t;
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/**
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* Private data of an random_rng_t object.
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*/
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struct private_random_rng_t {
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/**
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* Public random_rng_t interface.
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*/
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random_rng_t public;
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/**
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* random device, depends on quality
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*/
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int dev;
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/**
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* file we read random bytes from
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*/
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char *file;
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};
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/**
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* Implementation of random_rng_t.get_bytes.
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*/
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static void get_bytes(private_random_rng_t *this, size_t bytes,
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u_int8_t *buffer)
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{
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size_t done;
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ssize_t got;
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done = 0;
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while (done < bytes)
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{
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got = read(this->dev, buffer + done, bytes - done);
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if (got <= 0)
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{
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DBG1("reading from \"%s\" failed: %s, retrying...",
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this->file, strerror(errno));
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close(this->dev);
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sleep(1);
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this->dev = open(this->file, 0);
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}
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done += got;
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}
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}
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/**
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* Implementation of random_rng_t.allocate_bytes.
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*/
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static void allocate_bytes(private_random_rng_t *this, size_t bytes,
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chunk_t *chunk)
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{
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*chunk = chunk_alloc(bytes);
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get_bytes(this, chunk->len, chunk->ptr);
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}
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/**
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* Implementation of random_rng_t.destroy.
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*/
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static void destroy(private_random_rng_t *this)
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{
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close(this->dev);
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free(this);
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}
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/*
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* Described in header.
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*/
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random_rng_t *random_rng_create(rng_quality_t quality)
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{
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private_random_rng_t *this = malloc_thing(private_random_rng_t);
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/* public functions */
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this->public.rng.get_bytes = (void (*) (rng_t *, size_t, u_int8_t*)) get_bytes;
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this->public.rng.allocate_bytes = (void (*) (rng_t *, size_t, chunk_t*)) allocate_bytes;
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this->public.rng.destroy = (void (*) (rng_t *))destroy;
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if (quality == RNG_TRUE)
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{
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this->file = DEV_RANDOM;
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}
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else
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{
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this->file = DEV_URANDOM;
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}
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this->dev = open(this->file, 0);
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if (this->dev < 0)
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{
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DBG1("opening \"%s\" failed: %s", this->file, strerror(errno));
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free(this);
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return NULL;
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}
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return &this->public;
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}
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