/*-

 * Copyright (c) 2014 Michihiro NAKAJIMA

 * 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.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``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 AUTHOR(S) 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 "archive_platform.h"

__FBSDID("$FreeBSD$");

#ifdef HAVE_STDLIB_H

#include <stdlib.h>

#endif

#if !defined(HAVE_ARC4RANDOM_BUF) && (!defined(_WIN32) || defined(__CYGWIN__))

#ifdef HAVE_FCNTL

#include <fcntl.h>

#endif

#ifdef HAVE_LIMITS_H

#include <limits.h>

#endif

#ifdef HAVE_UNISTD_H

#include <unistd.h>

#endif

#ifdef HAVE_SYS_TYPES_H

#include <sys/types.h>

#endif

#ifdef HAVE_SYS_TIME_H

#include <sys/time.h>

#endif

#ifdef HAVE_PTHREAD_H

#include <pthread.h>

#endif

static void arc4random_buf(void *, size_t);

#endif /* HAVE_ARC4RANDOM_BUF */

#include "archive.h"

#include "archive_random_private.h"

#if defined(HAVE_WINCRYPT_H) && !defined(__CYGWIN__)

#include <wincrypt.h>

#endif

#ifndef O_CLOEXEC

#define O_CLOEXEC	0

#endif

/*

 * Random number generator function.

 * This simply calls arc4random_buf function if the platform provides it.

 */

int

archive_random(void *buf, size_t nbytes)

{

#if defined(_WIN32) && !defined(__CYGWIN__)

	HCRYPTPROV hProv;

	BOOL success;

	success = CryptAcquireContext(&hProv, NULL, NULL, PROV_RSA_FULL,

	    CRYPT_VERIFYCONTEXT);

	if (!success && GetLastError() == (DWORD)NTE_BAD_KEYSET) {

		success = CryptAcquireContext(&hProv, NULL, NULL,

		    PROV_RSA_FULL, CRYPT_NEWKEYSET);

	}

	if (success) {

		success = CryptGenRandom(hProv, (DWORD)nbytes, (BYTE*)buf);

		CryptReleaseContext(hProv, 0);

		if (success)

			return ARCHIVE_OK;

	}

	/* TODO: Does this case really happen? */

	return ARCHIVE_FAILED;

#else

	arc4random_buf(buf, nbytes);

	return ARCHIVE_OK;

#endif

}

#if !defined(HAVE_ARC4RANDOM_BUF) && (!defined(_WIN32) || defined(__CYGWIN__))

/*	$OpenBSD: arc4random.c,v 1.24 2013/06/11 16:59:50 deraadt Exp $	*/

/*

 * Copyright (c) 1996, David Mazieres <dm@uun.org>

 * Copyright (c) 2008, Damien Miller <djm@openbsd.org>

 *

 * Permission to use, copy, modify, and distribute this software for any

 * purpose with or without fee is hereby granted, provided that the above

 * copyright notice and this permission notice appear in all copies.

 *

 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES

 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF

 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR

 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES

 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN

 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF

 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

 */

/*

 * Arc4 random number generator for OpenBSD.

 *

 * This code is derived from section 17.1 of Applied Cryptography,

 * second edition, which describes a stream cipher allegedly

 * compatible with RSA Labs "RC4" cipher (the actual description of

 * which is a trade secret).  The same algorithm is used as a stream

 * cipher called "arcfour" in Tatu Ylonen's ssh package.

 *

 * RC4 is a registered trademark of RSA Laboratories.

 */

#ifdef __GNUC__

#define inline __inline

#else				/* !__GNUC__ */

#define inline

#endif				/* !__GNUC__ */

struct arc4_stream {

	uint8_t i;

	uint8_t j;

	uint8_t s[256];

};

#define	RANDOMDEV	"/dev/urandom"

#define	KEYSIZE		128

#ifdef HAVE_PTHREAD_H

static pthread_mutex_t	arc4random_mtx = PTHREAD_MUTEX_INITIALIZER;

#define	_ARC4_LOCK()	pthread_mutex_lock(&arc4random_mtx);

#define	_ARC4_UNLOCK()  pthread_mutex_unlock(&arc4random_mtx);

#else

#define	_ARC4_LOCK()

#define	_ARC4_UNLOCK()

#endif

static int rs_initialized;

static struct arc4_stream rs;

static pid_t arc4_stir_pid;

static int arc4_count;

static inline uint8_t arc4_getbyte(void);

static void arc4_stir(void);

static inline void

arc4_init(void)

{

	int     n;

	for (n = 0; n < 256; n++)

		rs.s[n] = n;

	rs.i = 0;

	rs.j = 0;

}

static inline void

arc4_addrandom(u_char *dat, int datlen)

{

	int     n;

	uint8_t si;

	rs.i--;

	for (n = 0; n < 256; n++) {

		rs.i = (rs.i + 1);

		si = rs.s[rs.i];

		rs.j = (rs.j + si + dat[n % datlen]);

		rs.s[rs.i] = rs.s[rs.j];

		rs.s[rs.j] = si;

	}

	rs.j = rs.i;

}

static void

arc4_stir(void)

{

	int done, fd, i;

	struct {

		struct timeval	tv;

		pid_t		pid;

		u_char	 	rnd[KEYSIZE];

	} rdat;

	if (!rs_initialized) {

		arc4_init();

		rs_initialized = 1;

	}

	done = 0;

	fd = open(RANDOMDEV, O_RDONLY | O_CLOEXEC, 0);

	if (fd >= 0) {

		if (read(fd, &rdat, KEYSIZE) == KEYSIZE)

			done = 1;

		(void)close(fd);

	}

	if (!done) {

		(void)gettimeofday(&rdat.tv, NULL);

		rdat.pid = getpid();

		/* We'll just take whatever was on the stack too... */

	}

	arc4_addrandom((u_char *)&rdat, KEYSIZE);

	/*

	 * Discard early keystream, as per recommendations in:

	 * "(Not So) Random Shuffles of RC4" by Ilya Mironov.

	 * As per the Network Operations Division, cryptographic requirements

	 * published on wikileaks on March 2017.

	 */

	for (i = 0; i < 3072; i++)

		(void)arc4_getbyte();

	arc4_count = 1600000;

}

static void

arc4_stir_if_needed(void)

{

	pid_t pid = getpid();

	if (arc4_count <= 0 || !rs_initialized || arc4_stir_pid != pid) {

		arc4_stir_pid = pid;

		arc4_stir();

	}

}

static inline uint8_t

arc4_getbyte(void)

{

	uint8_t si, sj;

	rs.i = (rs.i + 1);

	si = rs.s[rs.i];

	rs.j = (rs.j + si);

	sj = rs.s[rs.j];

	rs.s[rs.i] = sj;

	rs.s[rs.j] = si;

	return (rs.s[(si + sj) & 0xff]);

}

static void

arc4random_buf(void *_buf, size_t n)

{

	u_char *buf = (u_char *)_buf;

	_ARC4_LOCK();

	arc4_stir_if_needed();

	while (n--) {

		if (--arc4_count <= 0)

			arc4_stir();

		buf[n] = arc4_getbyte();

	}

	_ARC4_UNLOCK();

}

#endif /* !HAVE_ARC4RANDOM_BUF */