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freebsd/sys/vm/memguard.h
Matthew D Fleming e3813573bd Rework memguard(9) to reserve significantly more KVA to detect
use-after-free over a longer time.  Also release the backing pages of
a guarded allocation at free(9) time to reduce the overhead of using
memguard(9).  Allow setting and varying the malloc type at run-time.
Add knobs to allow:

 - randomly guarding memory
 - adding un-backed KVA guard pages to detect underflow and overflow
 - a lower limit on the size of allocations that are guarded

Reviewed by:    alc
Reviewed by:    brueffer, Ulrich Spörlein <uqs spoerlein net> (man page)
Silence from:   -arch
Approved by:    zml (mentor)
MFC after:      1 month
2010-08-11 22:10:37 +00:00

46 lines
1.9 KiB
C

/*-
* Copyright (c) 2005,
* Bosko Milekic <bmilekic@FreeBSD.org>. 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 unmodified, 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 ``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.
*
* $FreeBSD$
*/
#include "opt_vm.h"
#ifdef DEBUG_MEMGUARD
unsigned long memguard_fudge(unsigned long, unsigned long);
void memguard_init(struct vm_map *);
void *memguard_alloc(unsigned long, int);
void memguard_free(void *);
int memguard_cmp(struct malloc_type *, unsigned long);
int is_memguard_addr(void *);
#else
#define memguard_fudge(size, xxx) (size)
#define memguard_init(map) do { } while (0)
#define memguard_alloc(size, flags) NULL
#define memguard_free(addr) do { } while (0)
#define memguard_cmp(mtp, size) 0
#define is_memguard_addr(addr) 0
#endif