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From 529a388ebb1b4e9d6ad8a1bb61dd8211833a5976 Mon Sep 17 00:00:00 2001
From: Denis Lisov <dennis.lissov@gmail.com>
Date: Sat, 19 Dec 2015 19:13:58 +0300
Subject: [PATCH] libsandbox: fix old_malloc_size check on realloc
Realloc uses SB_MALLOC_TO_SIZE assuming it returns the usable size,
while it is really the mmap size, which is greater. Thus it may fail
to reallocate even if required.
URL: https://bugs.gentoo.org/568714
Signed-off-by: Denis Lisov <dennis.lissov@gmail.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
---
libsandbox/memory.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/libsandbox/memory.c b/libsandbox/memory.c
index 8581128..a2d69a2 100644
--- a/libsandbox/memory.c
+++ b/libsandbox/memory.c
@@ -40,7 +40,8 @@ static int sb_munmap(void *addr, size_t length)
#define SB_MALLOC_TO_MMAP(ptr) ((void*)((uintptr_t)(ptr) - MIN_ALIGN))
#define SB_MMAP_TO_MALLOC(ptr) ((void*)((uintptr_t)(ptr) + MIN_ALIGN))
-#define SB_MALLOC_TO_SIZE(ptr) (*((size_t*)SB_MALLOC_TO_MMAP(ptr)))
+#define SB_MALLOC_TO_MMAP_SIZE(ptr) (*((size_t*)SB_MALLOC_TO_MMAP(ptr)))
+#define SB_MALLOC_TO_SIZE(ptr) (SB_MALLOC_TO_MMAP_SIZE(ptr) - MIN_ALIGN)
void *malloc(size_t size)
{
@@ -57,7 +58,7 @@ void free(void *ptr)
{
if (ptr == NULL)
return;
- if (munmap(SB_MALLOC_TO_MMAP(ptr), SB_MALLOC_TO_SIZE(ptr)))
+ if (munmap(SB_MALLOC_TO_MMAP(ptr), SB_MALLOC_TO_MMAP_SIZE(ptr)))
sb_ebort("sandbox memory corruption with free(%p): %s\n",
ptr, strerror(errno));
}
--
2.6.2
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