freebsd-src/lib/libc/secure/memcpy_chk.c
Kyle Evans c10d567ea0 include: de-macro __ssp_overlap(), improve semantics and checking
Switch away from pointer arithmetic to provide more obvious semantics
for checking overlap on pointer ranges.  This lets us remove some casts
that need not exist and removes some possible fragility in its use.

While we're here, check for overflow just in case; sometimes we use a
caller-supplied size if __builtin_object_size(3) can't deduce the buffer
size, and we should fail the check if the size is nonsensical for the
provided buffers.

Reviewed by:	markj
Sponsored by:	Klara, Inc.
Sponsored by:	Stormshield
2024-07-13 00:16:23 -05:00

52 lines
1.9 KiB
C

/*-
*
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (c) 2006 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Christos Zoulas.
*
* 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 NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``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 FOUNDATION OR CONTRIBUTORS
* 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>
__RCSID("$NetBSD: memcpy_chk.c,v 1.7 2015/05/13 19:57:16 joerg Exp $");
#include <string.h>
#include <ssp/string.h>
#undef memcpy
void *
__memcpy_chk(void * __restrict dst, const void * __restrict src, size_t len,
size_t slen)
{
if (len > slen)
__chk_fail();
if (__ssp_overlap(src, dst, len))
__chk_fail();
return (memcpy(dst, src, len));
}