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Revision 1.3, Tue Oct 12 15:25:39 2021 UTC (7 weeks, 1 day ago) by nia
Branch: MAIN
CVS Tags: HEAD
Changes since 1.2: +18 -3 lines

crypt(3): match the Argon2 reference implementation's Base64 exactly

There are too many minor variations regarding padding and exact alphabet
to safely use the implementation in libc or an existing implementation
in libcrypt.

/*	$NetBSD: util.c,v 1.3 2021/10/12 15:25:39 nia Exp $	*/
/*
 * Copyright 1997 Niels Provos <provos@physnet.uni-hamburg.de>
 * 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by Niels Provos.
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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 <sys/cdefs.h>
#if !defined(lint)
__RCSID("$NetBSD: util.c,v 1.3 2021/10/12 15:25:39 nia Exp $");
#endif /* not lint */

#include <sys/types.h>
#include <errno.h>
#include <limits.h>
#include <stddef.h>
#include <stdlib.h>

#include "crypt.h"

/* traditional unix "B64" encoding */
static const unsigned char itoa64[] =		/* 0 ... 63 => ascii - 64 */
	"./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";

/* standard base64 encoding, used by Argon2 */
static const unsigned char itoabase64[] =
	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

crypt_private int
getnum(const char *str, size_t *num)
{
	char *ep;
	unsigned long rv;

	if (str == NULL) {
		*num = 0;
		return 0;
	}

	rv = strtoul(str, &ep, 0);

	if (str == ep || *ep) {
		errno = EINVAL;
		return -1;
	}

	if (errno == ERANGE && rv == ULONG_MAX)
		return -1;
	*num = (size_t)rv;
	return 0;
}

crypt_private void
__crypt_to64(char *s, uint32_t v, int n)
{

	while (--n >= 0) {
		*s++ = itoa64[v & 0x3f];
		v >>= 6;
	}
}

crypt_private void
__crypt_tobase64(char *s, uint32_t v, int n)
{

	while (--n >= 0) {
		*s++ = itoabase64[v & 0x3f];
		v >>= 6;
	}
}