diff options
| author | Eric W. Biederman | 2012-08-02 08:35:35 -0700 |
|---|---|---|
| committer | Eric W. Biederman | 2012-11-19 05:59:13 -0800 |
| commit | 225778d68d98e7cfe2579f8d8b2d7b76f8541b8b (patch) | |
| tree | d4bc4b78c3e19821eaaffacc5341d02328bcd3c9 | |
| parent | af4b8a83add95ef40716401395b44a1b579965f4 (diff) | |
pidns: Deny strange cases when creating pid namespaces.
task_active_pid_ns(current) != current->ns_proxy->pid_ns will
soon be allowed to support unshare and setns.
The definition of creating a child pid namespace when
task_active_pid_ns(current) != current->ns_proxy->pid_ns could be that
we create a child pid namespace of current->ns_proxy->pid_ns. However
that leads to strange cases like trying to have a single process be
init in multiple pid namespaces, which is racy and hard to think
about.
The definition of creating a child pid namespace when
task_active_pid_ns(current) != current->ns_proxy->pid_ns could be that
we create a child pid namespace of task_active_pid_ns(current). While
that seems less racy it does not provide any utility.
Therefore define the semantics of creating a child pid namespace when
task_active_pid_ns(current) != current->ns_proxy->pid_ns to be that the
pid namespace creation fails. That is easy to implement and easy
to think about.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
| -rw-r--r-- | kernel/pid_namespace.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c index 3cc29b830e9e..0dbbc66b6ec6 100644 --- a/kernel/pid_namespace.c +++ b/kernel/pid_namespace.c @@ -146,6 +146,8 @@ struct pid_namespace *copy_pid_ns(unsigned long flags, return get_pid_ns(old_ns); if (flags & (CLONE_THREAD|CLONE_PARENT)) return ERR_PTR(-EINVAL); + if (task_active_pid_ns(current) != old_ns) + return ERR_PTR(-EINVAL); return create_pid_namespace(user_ns, old_ns); } |