CVE-2024-26874

medium

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.

References

https://lists.debian.org/debian-lts-announce/2024/06/msg00020.html

https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html

https://git.kernel.org/stable/c/dfde84cc6c589f2a9f820f12426d97365670b731

https://git.kernel.org/stable/c/d2bd30c710475b2e29288827d2c91f9e6e2b91d7

https://git.kernel.org/stable/c/c958e86e9cc1b48cac004a6e245154dfba8e163b

https://git.kernel.org/stable/c/accdac6b71d5a2b84040c3d2234f53a60edc398e

https://git.kernel.org/stable/c/a3dd12b64ae8373a41a216a0b621df224210860a

https://git.kernel.org/stable/c/9beec711a17245b853d64488fd5b739031612340

https://git.kernel.org/stable/c/9acee29a38b4d4b70f1f583e5ef9a245db4db710

https://git.kernel.org/stable/c/4688be96d20ffa49d2186523ee84f475f316fd49

https://git.kernel.org/stable/c/3fc88b246a2fc16014e374040fc15af1d3752535

Details

Source: Mitre, NVD

Published: 2024-04-17

Updated: 2024-06-27

Risk Information

CVSS v2

Base Score: 4.6

Vector: CVSS2#AV:L/AC:L/Au:S/C:N/I:N/A:C

Severity: Medium

CVSS v3

Base Score: 5.5

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Severity: Medium