From 2c21d34ea44d38835f85b90de3cbbf54abb894be Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michaelni@gmx.at>
Date: Fri, 22 Feb 2013 20:30:52 +0100
Subject: [PATCH] avutil/mem: do a small set of checks for memalign hack before
freeing.
These can detect some kinds of memory and or pointer corruptions
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
---
libavutil/mem.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/libavutil/mem.c b/libavutil/mem.c
index 250b5f745ef..6d3efaabfa3 100644
--- a/libavutil/mem.c
+++ b/libavutil/mem.c
@@ -36,6 +36,7 @@
#include <malloc.h>
#endif
+#include "avassert.h"
#include "avutil.h"
#include "intreadwrite.h"
#include "mem.h"
@@ -148,6 +149,7 @@ void *av_realloc(void *ptr, size_t size)
if (!ptr)
return av_malloc(size);
diff = ((char *)ptr)[-1];
+ av_assert0(diff>0 && diff<=ALIGN);
ptr = realloc((char *)ptr - diff, size + diff);
if (ptr)
ptr = (char *)ptr + diff;
@@ -177,8 +179,11 @@ void *av_realloc_f(void *ptr, size_t nelem, size_t elsize)
void av_free(void *ptr)
{
#if CONFIG_MEMALIGN_HACK
- if (ptr)
- free((char *)ptr - ((char *)ptr)[-1]);
+ if (ptr) {
+ int v= ((char *)ptr)[-1];
+ av_assert0(v>0 && v<=ALIGN);
+ free((char *)ptr - v);
+ }
#elif HAVE_ALIGNED_MALLOC
_aligned_free(ptr);
#else
--
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