CVE-2024-26721 drm/i915/dsc: Fix the macro that calculates DSCC_/DSCA_ PPS reg address
Incorrect register address calculation in the Linux kernel i915 driver causes Display Stream Compression corruption, requiring a kernel patch.
- 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-2024-26721?
CVE-2024-26721 is a medium-severity vulnerability in Linux kernel, published on 3 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/i915/dsc: Fix the macro that calculates DSCC_/DSCA_ PPS reg address
Commit bd077259d0a9 ("drm/i915/vdsc: Add function to read any PPS register") defines a new macro to calculate the DSC PPS register addresses with PPS number as an input. This macro correctly calculates the addresses till PPS 11 since the addresses increment by 4. So in that case the following macro works correctly to give correct register address:
_MMIO(_DSCA_PPS_0 + (pps) * 4)
However after PPS 11, the register address for PPS 12 increments by 12 because of RC Buffer memory allocation in between. Because of this discontinuity in the address space, the macro calculates wrong addresses for PPS 12 - 16 resulting into incorrect DSC PPS parameter value read/writes causing DSC corruption.
This fixes it by correcting this macro to add the offset of 12 for PPS >=12.
v3: Add correct paranthesis for pps argument (Jani Nikula)
(cherry picked from commit 6074be620c31dc2ae11af96a1a5ea95580976fb5)
Weakness: CWE-131
Which versions are affected by CVE-2024-26721?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2024-26721?
Apply the vendor's patch.
Is CVE-2024-26721 being exploited?
There is no known exploitation of CVE-2024-26721 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2024-26721, DEBIAN-CVE-2024-26721, GHSA-wr7h-84qc-v963, UBUNTU-CVE-2024-26721.