userns: Convert sched_set_affinity and sched_set_scheduler's permission checks

- Compare kuids with uid_eq
- kuid are uniuqe across all user namespaces so there is no longer the
  need for a user_namespace comparison.

Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

1 files changed, 2 insertions, 5 deletions

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 96bff855b86..b189fecaef9 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -4042,11 +4042,8 @@ static bool check_same_owner(struct task_struct *p)
 
         rcu_read_lock();
         pcred = __task_cred(p);
-        if (cred->user_ns == pcred->user_ns)
-                match = (cred->euid == pcred->euid ||
-                         cred->euid == pcred->uid);
-        else
-                match = false;
+        match = (uid_eq(cred->euid, pcred->euid) ||
+                 uid_eq(cred->euid, pcred->uid));
         rcu_read_unlock();
         return match;
 }