In the Linux kernel, the following vulnerability has been resolved:
drm/xe/hdcp: Add NULL check for media_gt in intel_hdcp_gsc_check_status()
When media GT is disabled via configfs, there is no allocation for media_gt, which is kept as NULL. In such scenario, intel_hdcp_gsc_check_status() results in a kernel pagefault error due to >->uc.gsc being evaluated as an invalid memory address.
Fix that by introducing a NULL check on media_gt and bailing out early if so.
While at it, also drop the NULL check for gsc, since it can't be NULL if media_gt is not NULL.
v2:
- Get address for gsc only after checking that gt is not NULL.
- Drop the NULL check for gsc. (Shuicheng)
- Add "Fixes" and "Cc: " tags. (Matt)
(cherry picked from commit bfaf87e84ca3ca3f6e275f9ae56da47a8b55ffd1)