audit: Use struct net not pid_t to remember the network namespce to reply in

In struct audit_netlink_list and audit_reply add a reference to the
network namespace of the caller and remove the userspace pid of the
caller.  This cleanly remembers the callers network namespace, and
removes a huge class of races and nasty failure modes that can occur
when attempting to relook up the callers network namespace from a
pid_t (including the caller's network namespace changing, pid
wraparound, and the pid simply not being present).

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index 14a78cca384e..a5e3d73d73e4 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -29,6 +29,7 @@
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/security.h>
+#include <net/net_namespace.h>
 #include "audit.h"
 
 /*
@@ -1083,8 +1084,8 @@ int audit_list_rules_send(__u32 portid, int seq)
 	dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
 	if (!dest)
 		return -ENOMEM;
+	dest->net = get_net(current->nsproxy->net_ns);
 	dest->portid = portid;
-	dest->pid = task_pid_vnr(current);
 	skb_queue_head_init(&dest->q);
 
 	mutex_lock(&audit_filter_mutex);