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wl_array: Set data to invalid address after free

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Explicitly set the data member to an invalid memory address during
wl_array_release, such that re-using a freed wl_array without re-initializing
causes a crash. In addition, this pointer assignment makes wl_array_release
testable.

Define a constant for the invalid memory address, and add documentation about
this behavior, starting at libwayland version 1.13.

See https://lists.freedesktop.org/archives/wayland-devel/2016-September/031116.html

Signed-off-by: Yong Bakos <ybakos@humanoriented.com>
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>
[Pekka: remove the doc about crashing]
Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
This commit is contained in:
Yong Bakos 2016-09-27 13:03:48 -05:00 • committed by Pekka Paalanen
parent db61796026
commit e8ad23266f
2 changed files with 4 additions and 0 deletions
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3
src/wayland-private.h
View file

@ -36,6 +36,9 @@
#include "wayland-util.h"
/* Invalid memory address */
#define WL_ARRAY_POISON_PTR (void *) 4
#define ARRAY_LENGTH(a) (sizeof (a) / sizeof (a)[0])
#define container_of(ptr, type, member) ({ \

1
src/wayland-util.c
View file

@ -102,6 +102,7 @@ WL_EXPORT void
wl_array_release(struct wl_array *array)
{
free(array->data);
array->data = WL_ARRAY_POISON_PTR;
}
WL_EXPORT void *