CVE-2024-56777

What it actually does

Failure to validate the return value from drm_atomic_get_crtc_state() allows an error pointer to be dereferenced inside sti_gdp_atomic_check, resulting in invalid memory access.

Why it matters to the business

Potential system crashes or denial-of-service on Linux systems using the STI DRM driver; low exploitation likelihood reduces immediate operational risk despite presence in older distributions.

How an attack unfolds

An attacker with local access crafts graphics or atomic state operations that trigger drm_atomic_get_crtc_state failure; the unchecked error pointer is then used, leading to a kernel fault. Threat actors noted in broader Linux kernel out-of-bounds campaigns could attempt similar local triggers.

How to fix it

Update the Linux kernel to a version containing the fix for the STI driver error-pointer check; for the listed chromium-browser packages on Ubuntu 14.04 LTS apply version 53.0.2785.143-0ubuntu0.14.04.1.1142 or newer.

How to confirm the fix worked

Confirm the patched kernel source contains the added return-value check after drm_atomic_get_crtc_state; verify package version matches the fixed release and test atomic DRM operations do not crash.

Typical attack path

1. Obtain local code execution on target system
2. Trigger DRM atomic state operations that cause drm_atomic_get_crtc_state to return an error
3. Force subsequent dereference of the unchecked error pointer
4. Induce kernel panic or memory corruption

How to detect it

Review kernel logs for oops or panic messages referencing sti_gdp_atomic_check or drm_atomic_get_crtc_state; correlate with process activity attempting DRM atomic operations.

What your security team should do

• Apply the kernel or chromium update immediately on affected systems
• Monitor for kernel oops or panic logs related to sti_gdp_atomic_check
• Restrict local unprivileged access until patches are deployed