CVE-2024-26874 drm/mediatek: Fix a null pointer crash in mtk_drm_crtc_finish_page_flip
A race condition in the Mediatek DRM driver causes a null pointer dereference, leading to a kernel crash and denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2024-26874?
CVE-2024-26874 is a medium-severity vulnerability in Debian Debian Linux, published on 17 Apr 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
drm/mediatek: Fix a null pointer crash in mtk_drm_crtc_finish_page_flip
It's possible that mtk_crtc->event is NULL in mtk_drm_crtc_finish_page_flip().
pending_needs_vblank value is set by mtk_crtc->event, but in mtk_drm_crtc_atomic_flush(), it's is not guarded by the same lock in mtk_drm_finish_page_flip(), thus a race condition happens.
Consider the following case:
CPU1 CPU2 step 1: mtk_drm_crtc_atomic_begin() mtk_crtc->event is not null, step 1: mtk_drm_crtc_atomic_flush: mtk_drm_crtc_update_config( !!mtk_crtc->event) step 2: mtk_crtc_ddp_irq -> mtk_drm_finish_page_flip: lock mtk_crtc->event set to null, pending_needs_vblank set to false unlock pending_needs_vblank set to true,
step 2: mtk_crtc_ddp_irq -> mtk_drm_finish_page_flip called again, pending_needs_vblank is still true //null pointer
Instead of guarding the entire mtk_drm_crtc_atomic_flush(), it's more efficient to just check if mtk_crtc->event is null before use.
Weakness: CWE-476
Which versions are affected by CVE-2024-26874?
It affects 2 products.
Products include Debian Debian Linux, Linux kernel.
How do I fix CVE-2024-26874?
Apply the vendor's patch.
Is CVE-2024-26874 being exploited?
There is no known exploitation of CVE-2024-26874 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as BELL-CVE-2024-26874, DEBIAN-CVE-2024-26874, GHSA-q342-fw2j-5cj8, UBUNTU-CVE-2024-26874.