device_cgroup: Cleanup cgroup eBPF device filter code

Original cgroup v2 eBPF code for filtering device access made it
possible to compile with CONFIG_CGROUP_DEVICE=n and still use the eBPF
filtering. Change
commit 4b7d4d453f ("device_cgroup: Export devcgroup_check_permission")
reverted this, making it required to set it to y.

Since the device filtering (and all the docs) for cgroup v2 is no longer
a "device controller" like it was in v1, someone might compile their
kernel with CONFIG_CGROUP_DEVICE=n. Then (for linux 5.5+) the eBPF
filter will not be invoked, and all processes will be allowed access
to all devices, no matter what the eBPF filter says.

Signed-off-by: Odin Ugedal <odin@ugedal.com>
Acked-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Odin Ugedal
2020-04-03 19:55:28 +02:00
committed by Tejun Heo
parent 772b314066
commit eec8fd0277
4 changed files with 23 additions and 14 deletions

View File

@ -1050,7 +1050,7 @@ void kfd_dec_compute_active(struct kfd_dev *dev);
/* Check with device cgroup if @kfd device is accessible */
static inline int kfd_devcgroup_check_permission(struct kfd_dev *kfd)
{
#if defined(CONFIG_CGROUP_DEVICE)
#if defined(CONFIG_CGROUP_DEVICE) || defined(CONFIG_CGROUP_BPF)
struct drm_device *ddev = kfd->ddev;
return devcgroup_check_permission(DEVCG_DEV_CHAR, ddev->driver->major,