| Message ID | 20250304083927.37681-1-gerben@altlinux.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | block/qed: fix use-after-free by nullifying timer pointer after free | expand |
On Tue, Mar 04, 2025 at 11:39:10AM +0300, gerben@altlinux.org wrote: > From: Denis Rastyogin <gerben@altlinux.org> > > This error was discovered by fuzzing qemu-img. > > In the QED block driver, the need_check_timer timer is freed in > bdrv_qed_detach_aio_context, but the pointer to the timer is not > set to NULL. This can lead to a use-after-free scenario > in bdrv_qed_drain_begin(). > > The need_check_timer pointer is set to NULL after freeing the timer. > Which helps catch this condition when checking in bdrv_qed_drain_begin(). > > Closes: https://gitlab.com/qemu-project/qemu/-/issues/2852 > Signed-off-by: Denis Rastyogin <gerben@altlinux.org> > --- > block/qed.c | 1 + > 1 file changed, 1 insertion(+) Thanks, applied to my block tree: https://gitlab.com/stefanha/qemu/commits/block Stefan
diff --git a/block/qed.c b/block/qed.c index 382c9e5335..ac24449ffb 100644 --- a/block/qed.c +++ b/block/qed.c @@ -353,6 +353,7 @@ static void bdrv_qed_detach_aio_context(BlockDriverState *bs) qed_cancel_need_check_timer(s); timer_free(s->need_check_timer); + s->need_check_timer = NULL; } static void bdrv_qed_attach_aio_context(BlockDriverState *bs,