pidns: deny CLONE_PARENT|CLONE_NEWPID combination
CLONE_PARENT was used to implement an older threading model. For
consistency with the CLONE_THREAD check in copy_pid_ns(), disable
CLONE_PARENT with CLONE_NEWPID, at least until the required semantics of
pid namespaces are clear.
Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Acked-by: Roland McGrath <roland@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Oren Laadan <orenl@cs.columbia.edu>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index 821722a..86b3796 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -118,7 +118,7 @@
{
if (!(flags & CLONE_NEWPID))
return get_pid_ns(old_ns);
- if (flags & CLONE_THREAD)
+ if (flags & (CLONE_THREAD|CLONE_PARENT))
return ERR_PTR(-EINVAL);
return create_pid_namespace(old_ns);
}