1 files changed, 21 insertions, 0 deletions

diff --git a/fs/namespace.c b/fs/namespace.c
index 968d4c5eae03..d581e45c0a9f 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -2763,6 +2763,27 @@ bool current_chrooted(void)
         return chrooted;
 }
 
+void update_mnt_policy(struct user_namespace *userns)
+{
+        struct mnt_namespace *ns = current->nsproxy->mnt_ns;
+        struct mount *mnt;
+
+        down_read(&namespace_sem);
+        list_for_each_entry(mnt, &ns->list, mnt_list) {
+                switch (mnt->mnt.mnt_sb->s_magic) {
+                case SYSFS_MAGIC:
+                        userns->may_mount_sysfs = true;
+                        break;
+                case PROC_SUPER_MAGIC:
+                        userns->may_mount_proc = true;
+                        break;
+                }
+                if (userns->may_mount_sysfs && userns->may_mount_proc)
+                        break;
+        }
+        up_read(&namespace_sem);
+}
+
 static void *mntns_get(struct task_struct *task)
 {
         struct mnt_namespace *ns = NULL;