device_cgroup: remove can_attach

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@ubuntu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Aristeu Rozanski <aris@redhat.com>

diff --git a/security/device_cgroup.c b/security/device_cgroup.c
index c123628..7c2a0a7 100644 (file)
--- 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,