Re: [PATCH] fpga: dfl: afu: prevent read-only port mappings from becoming writable

[Dinh Nguyen]

On 8/19/26 03:42, Abdifatah Suruur wrote:
> afu_mmap() rejects writable mappings of port regions without the WRITE
> flag, but leaves VM_MAYWRITE set.  Userspace can map such a region
> read-only and then upgrade the mapping to writable with mprotect(),
> writing to FPGA port control/status registers the host owns.  A guest
> assigned an AFU can use this to reconfigure or reset the port and
> interfere with other tenants on the same FPGA.
>
> Clear VM_MAYWRITE for regions without the WRITE flag, as i915 does for
> its read-only objects and as fixed in drm/vc4 (CVE-2026-68445) and
> drm/panthor (CVE-2024-53071) and ptp: vmclock (commit
> a5edadbae57e2298a56cf7a4e774a027905a331f).
>
> Fixes: 1a1527cf5ddac ("fpga: dfl: add FPGA Accelerated Function Unit driver basic framework")

Please used exactly 12 characters for the hash ID.

Dinh