CVE-2024-42118

What it actually does

The resource_stream_to_stream_idx helper can return -1 when a stream is not found; using this negative value as an array index enables out-of-bounds access and negative-return defects.

Why it matters to the business

Unpatched kernels on systems with AMD GPUs risk display driver crashes or memory corruption that can cause system instability or denial of service; widespread Linux deployments increase exposure.

How an attack unfolds

An attacker supplies display configuration or resource-mapping input that causes resource_stream_to_stream_idx to fail to locate a stream, resulting in a -1 return value that is subsequently used as an array index and triggers an overrun.

How to fix it

Apply the upstream fix in commit a76fa9c4f0fc0aa6f517da3fa7d7c23e8a32c7d0 or later; rebuild and deploy the updated kernel image on all affected AMD GPU systems.

How to confirm the fix worked

Confirm the running kernel contains commit a76fa9c4f0fc0aa6f517da3fa7d7c23e8a32c7d0; verify absence of Coverity OVERRUN/NEGATIVE_RETURNS reports on the fixed function.

Typical attack path

1. Trigger AMD display resource allocation or stream mapping path
2. Cause resource_stream_to_stream_idx lookup to fail
3. Use returned -1 value as array index
4. Induce overrun or negative-return condition

How to detect it

Review kernel logs for ASSERT failures or crashes originating from drm/amd/display resource stream handling; correlate with display reconfiguration events.

What your security team should do

• Prioritize kernel update to the fixed commit within standard patch windows
• Monitor AMD display driver stability metrics after deployment
• Include the change in next automated kernel rebuild pipeline