Commit 1a80dade authored Dec 28, 2018 by Matthew Wilcox Committed by Linus Torvalds Dec 28, 2018

Fix failure path in alloc_pid()



The failure path removes the allocated PIDs from the wrong namespace.
This could lead to us inadvertently reusing PIDs in the leaf namespace
and leaking PIDs in parent namespaces.

Fixes: 95846ecf ("pid: replace pid bitmap implementation with IDR API")
Cc: <stable@vger.kernel.org>
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 00c569b5

kernel/pid.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -233,8 +233,10 @@ struct pid alloc_pid(struct pid_namespace ns)

		out_free:
		spin_lock_irq(&pidmap_lock);
		while (++i <= ns->level)
		idr_remove(&ns->idr, (pid->numbers + i)->nr);
		while (++i <= ns->level) {
		upid = pid->numbers + i;
		idr_remove(&upid->ns->idr, upid->nr);
		}

		/* On failure to allocate the first pid, reset the state */
		if (ns->pid_allocated == PIDNS_ADDING)