1 files changed, 13 insertions, 4 deletions

diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index d8c30db06c5b..9064b919a406 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -62,6 +62,9 @@ int create_user_ns(struct cred *new)
         kgid_t group = new->egid;
         int ret;
 
+        if (parent_ns->level > 32)
+                return -EUSERS;
+
         /*
          * Verify that we can not violate the policy of which files
          * may be accessed that is specified by the root directory,
@@ -92,6 +95,7 @@ int create_user_ns(struct cred *new)
         atomic_set(&ns->count, 1);
         /* Leave the new->user_ns reference with the new user namespace. */
         ns->parent = parent_ns;
+        ns->level = parent_ns->level + 1;
         ns->owner = owner;
         ns->group = group;
 
@@ -105,16 +109,21 @@ int create_user_ns(struct cred *new)
 int unshare_userns(unsigned long unshare_flags, struct cred **new_cred)
 {
         struct cred *cred;
+        int err = -ENOMEM;
 
         if (!(unshare_flags & CLONE_NEWUSER))
                 return 0;
 
         cred = prepare_creds();
-        if (!cred)
-                return -ENOMEM;
+        if (cred) {
+                err = create_user_ns(cred);
+                if (err)
+                        put_cred(cred);
+                else
+                        *new_cred = cred;
+        }
 
-        *new_cred = cred;
-        return create_user_ns(cred);
+        return err;
 }
 
 void free_user_ns(struct user_namespace *ns)