[PATCH 1/1] device_cgroup: remove can_attach

[Serge Hallyn]

[ Hi - the following patch has been applied to Tejun's
cgroup/for-3.13 branch.  It's needed for non-root users to be
able to create containers ]

It is really only wanting to duplicate a check which is already done by the
cgroup subsystem.

With this patch, user jdoe still cannot move pid 1 into a devices cgroup
he owns, but now he can move his own other tasks into devices cgroups.

Signed-off-by: Serge Hallyn <serge.hallyn at ubuntu.com>
Signed-off-by: Tejun Heo <tj at kernel.org>
Cc: Aristeu Rozanski <aris at redhat.com>
---
 security/device_cgroup.c |   11 -----------
 1 file changed, 11 deletions(-)

diff --git a/security/device_cgroup.c b/security/device_cgroup.c
index c123628..7c2a0a7 100644
--- a/security/device_cgroup.c
+++ b/security/device_cgroup.c
@@ -63,16 +63,6 @@ static inline struct dev_cgroup *task_devcgroup(struct task_struct *task)
 
 struct cgroup_subsys devices_subsys;
 
-static int devcgroup_can_attach(struct cgroup_subsys_state *new_css,
-				struct cgroup_taskset *set)
-{
-	struct task_struct *task = cgroup_taskset_first(set);
-
-	if (current != task && !capable(CAP_SYS_ADMIN))
-		return -EPERM;
-	return 0;
-}
-
 /*
  * called under devcgroup_mutex
  */
@@ -697,7 +687,6 @@ static struct cftype dev_cgroup_files[] = {
 
 struct cgroup_subsys devices_subsys = {
 	.name = "devices",
-	.can_attach = devcgroup_can_attach,
 	.css_alloc = devcgroup_css_alloc,
 	.css_free = devcgroup_css_free,
 	.css_online = devcgroup_online,
-- 
1.7.9.5