userns: user namespaces: convert several capable() calls

CAP_IPC_OWNER and CAP_IPC_LOCK can be checked against current_user_ns(),
because the resource comes from current's own ipc namespace.

setuid/setgid are to uids in own namespace, so again checks can be against
current_user_ns().

Changelog:
	Jan 11: Use task_ns_capable() in place of sched_capable().
	Jan 11: Use nsown_capable() as suggested by Bastian Blank.
	Jan 11: Clarify (hopefully) some logic in futex and sched.c
	Feb 15: use ns_capable for ipc, not nsown_capable
	Feb 23: let copy_ipcs handle setting ipc_ns->user_ns
	Feb 23: pass ns down rather than taking it from current

[akpm@linux-foundation.org: coding-style fixes]
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, 1 insertions, 6 deletions

diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index ac8a56e90bf8..a05d191ffdd9 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -75,16 +75,11 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
                 goto out_uts;
         }
 
-        new_nsp->ipc_ns = copy_ipcs(flags, tsk->nsproxy->ipc_ns);
+        new_nsp->ipc_ns = copy_ipcs(flags, tsk);
         if (IS_ERR(new_nsp->ipc_ns)) {
                 err = PTR_ERR(new_nsp->ipc_ns);
                 goto out_ipc;
         }
-        if (new_nsp->ipc_ns != tsk->nsproxy->ipc_ns) {
-                put_user_ns(new_nsp->ipc_ns->user_ns);
-                new_nsp->ipc_ns->user_ns = task_cred_xxx(tsk, user)->user_ns;
-                get_user_ns(new_nsp->ipc_ns->user_ns);
-        }
 
         new_nsp->pid_ns = copy_pid_ns(flags, task_active_pid_ns(tsk));
         if (IS_ERR(new_nsp->pid_ns)) {