userns: allow sethostname in a container

Changelog:
	Feb 23: let clone_uts_ns() handle setting uts->user_ns
		To do so we need to pass in the task_struct who'll
		get the utsname, so we can get its user_ns.
	Feb 23: As per Oleg's coment, just pass in tsk, instead of two
		of its members.

Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Daniel Lezcano <daniel.lezcano@free.fr>
Acked-by: David Howells <dhowells@redhat.com>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/include/linux/utsname.h b/include/linux/utsname.h
index 2c3c0f543705..4e5b0213fdc1 100644
--- a/include/linux/utsname.h
+++ b/include/linux/utsname.h
@@ -54,7 +54,7 @@ static inline void get_uts_ns(struct uts_namespace *ns)
 }
 
 extern struct uts_namespace *copy_utsname(unsigned long flags,
-                                        struct uts_namespace *ns);
+                                          struct task_struct *tsk);
 extern void free_uts_ns(struct kref *kref);
 
 static inline void put_uts_ns(struct uts_namespace *ns)
@@ -71,12 +71,12 @@ static inline void put_uts_ns(struct uts_namespace *ns)
 }
 
 static inline struct uts_namespace *copy_utsname(unsigned long flags,
-                                        struct uts_namespace *ns)
+                                                 struct task_struct *tsk)
 {
         if (flags & CLONE_NEWUTS)
                 return ERR_PTR(-EINVAL);
 
-        return ns;
+        return tsk->nsproxy->uts_ns;
 }
 #endif