vulkanoverlaycompositor: don't do a potential use after free

Removing a meta from a buffer means one doesn't have access to it
anymore.  Instead use the already reffed composition directly.

Fixes a use-after-free in the following pipeline:

... ! vulkanupload ! timeoverlay ! vulkanoverlaycompositor ! ...

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/4147>
This commit is contained in:
Matthew Waters 2023-03-10 16:47:17 +11:00 committed by Tim-Philipp Müller
parent d67aa49737
commit 7d2300efa1

View file

@ -729,6 +729,7 @@ gst_vulkan_overlay_compositor_transform_ip (GstBaseTransform * bt,
comp = gst_video_overlay_composition_ref (ometa->overlay);
gst_buffer_remove_meta (buffer, (GstMeta *) ometa);
ometa = NULL;
n = gst_video_overlay_composition_n_rectangles (comp);
if (n == 0) {
@ -765,7 +766,7 @@ gst_vulkan_overlay_compositor_transform_ip (GstBaseTransform * bt,
struct vk_overlay *over =
&g_array_index (vk_overlay->overlays, struct vk_overlay, i);
if (!overlay_in_rectangles (over, ometa->overlay)) {
if (!overlay_in_rectangles (over, comp)) {
g_array_remove_index (vk_overlay->overlays, i);
continue;
}