We were allowing any users to create a high priority group without any
permission checks. As a result, this was allowing possible denial of
service.
We now only allow the DRM master or users with the CAP_SYS_NICE
capability to set higher priorities than PANTHOR_GROUP_PRIORITY_MEDIUM.
As the sole user of that uAPI lives in Mesa and hardcode a value of
MEDIUM [1], this should be safe to do.
Additionally, as those checks are performed at the ioctl level,
panthor_group_create now only check for priority level validity.
[1]f390835074/src/gallium/drivers/panfrost/pan_csf.c (L1038)
Signed-off-by: Mary Guillemard <mary.guillemard@collabora.com>
Fixes: de85488138 ("drm/panthor: Add the scheduler logical block")
Cc: stable@vger.kernel.org
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240903144955.144278-2-mary.guillemard@collabora.com
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