audit: Use struct net not pid_t to remember the network namespce to reply in
While reading through 3.14-rc1 I found a pretty siginficant mishandling
of network namespaces in the recent audit changes.
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>
Acked-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
diff --git a/kernel/audit.c b/kernel/audit.c
index 34c5a23..71fb41f 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -182,7 +182,7 @@
struct audit_reply {
__u32 portid;
- pid_t pid;
+ struct net *net;
struct sk_buff *skb;
};
@@ -500,7 +500,7 @@
{
struct audit_netlink_list *dest = _dest;
struct sk_buff *skb;
- struct net *net = get_net_ns_by_pid(dest->pid);
+ struct net *net = dest->net;
struct audit_net *aunet = net_generic(net, audit_net_id);
/* wait for parent to finish and send an ACK */
@@ -510,6 +510,7 @@
while ((skb = __skb_dequeue(&dest->q)) != NULL)
netlink_unicast(aunet->nlsk, skb, dest->portid, 0);
+ put_net(net);
kfree(dest);
return 0;
@@ -543,7 +544,7 @@
static int audit_send_reply_thread(void *arg)
{
struct audit_reply *reply = (struct audit_reply *)arg;
- struct net *net = get_net_ns_by_pid(reply->pid);
+ struct net *net = reply->net;
struct audit_net *aunet = net_generic(net, audit_net_id);
mutex_lock(&audit_cmd_mutex);
@@ -552,6 +553,7 @@
/* Ignore failure. It'll only happen if the sender goes away,
because our timeout is set to infinite. */
netlink_unicast(aunet->nlsk , reply->skb, reply->portid, 0);
+ put_net(net);
kfree(reply);
return 0;
}
@@ -583,8 +585,8 @@
if (!skb)
goto out;
+ reply->net = get_net(current->nsproxy->net_ns);
reply->portid = portid;
- reply->pid = task_pid_vnr(current);
reply->skb = skb;
tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");