userns: Make create_new_namespaces take a user_ns parameter

Modify create_new_namespaces to explicitly take a user namespace
parameter, instead of implicitly through the task_struct.

This allows an implementation of unshare(CLONE_NEWUSER) where
the new user namespace is not stored onto the current task_struct
until after all of the namespaces are created.

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

1 files changed, 4 insertions, 5 deletions

diff --git a/kernel/utsname.c b/kernel/utsname.c
index 4a9362f9325d..fdc619eb61ef 100644
--- a/kernel/utsname.c
+++ b/kernel/utsname.c
@@ -32,7 +32,7 @@ static struct uts_namespace *create_uts_ns(void)
  * @old_ns: namespace to clone
  * Return NULL on error (failure to kmalloc), new ns otherwise
  */
-static struct uts_namespace *clone_uts_ns(struct task_struct *tsk,
+static struct uts_namespace *clone_uts_ns(struct user_namespace *user_ns,
                                           struct uts_namespace *old_ns)
 {
         struct uts_namespace *ns;
@@ -43,7 +43,7 @@ static struct uts_namespace *clone_uts_ns(struct task_struct *tsk,
 
         down_read(&uts_sem);
         memcpy(&ns->name, &old_ns->name, sizeof(ns->name));
-        ns->user_ns = get_user_ns(task_cred_xxx(tsk, user_ns));
+        ns->user_ns = get_user_ns(user_ns);
         up_read(&uts_sem);
         return ns;
 }
@@ -55,9 +55,8 @@ static struct uts_namespace *clone_uts_ns(struct task_struct *tsk,
  * versa.
  */
 struct uts_namespace *copy_utsname(unsigned long flags,
-                                   struct task_struct *tsk)
+        struct user_namespace *user_ns, struct uts_namespace *old_ns)
 {
-        struct uts_namespace *old_ns = tsk->nsproxy->uts_ns;
         struct uts_namespace *new_ns;
 
         BUG_ON(!old_ns);
@@ -66,7 +65,7 @@ struct uts_namespace *copy_utsname(unsigned long flags,
         if (!(flags & CLONE_NEWUTS))
                 return old_ns;
 
-        new_ns = clone_uts_ns(tsk, old_ns);
+        new_ns = clone_uts_ns(user_ns, old_ns);
 
         put_uts_ns(old_ns);
         return new_ns;