Description

In the Linux kernel, the following vulnerability has been resolved:

drm/mediatek: Set private->all_drm_private[i]->drm to NULL if mtk_drm_bind returns err

The pointer need to be set to NULL, otherwise KASAN complains about
use-after-free. Because in mtk_drm_bind, all private's drm are set
as follows.

private->all_drm_private[i]->drm = drm;

And drm will be released by drm_dev_put in case mtk_drm_kms_init returns
failure. However, the shutdown path still accesses the previous allocated
memory in drm_atomic_helper_shutdown.

[ 84.874820] watchdog: watchdog0: watchdog did not stop!
[ 86.512054] ==================================================================
[ 86.513162] BUG: KASAN: use-after-free in drm_atomic_helper_shutdown+0x33c/0x378
[ 86.514258] Read of size 8 at addr ffff0000d46fc068 by task shutdown/1
[ 86.515213]
[ 86.515455] CPU: 1 UID: 0 PID: 1 Comm: shutdown Not tainted 6.13.0-rc1-mtk+gfa1a78e5d24b-dirty #55
[ 86.516752] Hardware name: Unknown Product/Unknown Product, BIOS 2022.10 10/01/2022
[ 86.517960] Call trace:
[ 86.518333] show_stack+0x20/0x38 (C)
[ 86.518891] dump_stack_lvl+0x90/0xd0
[ 86.519443] print_report+0xf8/0x5b0
[ 86.519985] kasan_report+0xb4/0x100
[ 86.520526] __asan_report_load8_noabort+0x20/0x30
[ 86.521240] drm_atomic_helper_shutdown+0x33c/0x378
[ 86.521966] mtk_drm_shutdown+0x54/0x80
[ 86.522546] platform_shutdown+0x64/0x90
[ 86.523137] device_shutdown+0x260/0x5b8
[ 86.523728] kernel_restart+0x...

Classification

CVE ID: CVE-2024-57926

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.04% (probability of being exploited)

EPSS Percentile: 5.03% (scored less or equal to compared to others)

EPSS Date: 2025-02-17 (when was this score calculated)

References

https://git.kernel.org/stable/c/7083b93e9755d60f0c2bcaa9d064308108280534
https://git.kernel.org/stable/c/078b2ff7da200b7532398e668eef723ad40fb516
https://git.kernel.org/stable/c/36684e9d88a2e2401ae26715a2e217cb4295cea7

Timeline