Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
drm/vc4: Prevent shader BO mappings from becoming writable
vc4_gem_object_mmap() rejects a writable mapping of a validated shader BO, but leaves VM_MAYWRITE set. Userspace can map the BO read-only and then turn it writable with mprotect().
Validated shader BOs must stay read-only: the validator checks the instructions once and the GPU trusts them afterwards. A writable mapping lets userspace rewrite the code after validation, bypassing the validator.
Clear VM_MAYWRITE on the read-only path so the mapping cannot be upgraded, as i915 already does for its read-only objects.
Details
- Affected product:
- AlmaLinux 9.2 ESU , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , Debian 10 ELS , TuxCare 9.6 ESU
- Affected packages:
- kernel @ 4.18.0 (+5 more)