sudo/lib/util/arc4random_buf.c

71 lines
1.7 KiB
C

/*
* SPDX-License-Identifier: ISC
*
* Copyright (c) 2020 Todd C. Miller <Todd.Miller@sudo.ws>
*
* 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.
*/
/*
* This is an open source non-commercial project. Dear PVS-Studio, please check it.
* PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
*/
#include <config.h>
#ifndef HAVE_ARC4RANDOM_BUF
#include <stdlib.h>
#if defined(HAVE_STDINT_H)
# include <stdint.h>
#elif defined(HAVE_INTTYPES_H)
# include <inttypes.h>
#endif
#include <sudo_compat.h>
#include <sudo_rand.h>
#define minimum(a, b) ((a) < (b) ? (a) : (b))
/*
* Call arc4random() repeatedly to fill buf with n bytes of random data.
*/
void
sudo_arc4random_buf(void *buf, size_t n)
{
char *cp = buf;
while (n != 0) {
size_t m = minimum(n, 4);
uint32_t val = arc4random();
switch (m) {
case 4:
*cp++ = (val >> 24) & 0xff;
FALLTHROUGH;
case 3:
*cp++ = (val >> 16) & 0xff;
FALLTHROUGH;
case 2:
*cp++ = (val >> 8) & 0xff;
FALLTHROUGH;
case 1:
*cp++ = val & 0xff;
break;
}
n -= m;
}
}
#endif /* HAVE_ARC4RANDOM_BUF */