userns: Convert cgroup permission checks to use uid_eq

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

2 files changed, 3 insertions, 4 deletions

diff --git a/init/Kconfig b/init/Kconfig
index 7a5ccb2e9e0f..d24cc75caf65 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -865,7 +865,6 @@ config UIDGID_CONVERTED
 
         # List of kernel pieces that need user namespace work
         # Features
-        depends on CGROUPS = n
         depends on MIGRATION = n
         depends on NUMA = n
         depends on SYSVIPC = n
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index ed64ccac67c9..c8329b0c2576 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -2160,9 +2160,9 @@ retry_find_task:
                  * only need to check permissions on one of them.
                  */
                 tcred = __task_cred(tsk);
-                if (cred->euid &&
-                    cred->euid != tcred->uid &&
-                    cred->euid != tcred->suid) {
+                if (!uid_eq(cred->euid, GLOBAL_ROOT_UID) &&
+                    !uid_eq(cred->euid, tcred->uid) &&
+                    !uid_eq(cred->euid, tcred->suid)) {
                         rcu_read_unlock();
                         ret = -EACCES;
                         goto out_unlock_cgroup;