[XFRM]: Fix aevent related crash
When xfrm_user isn't loaded xfrm_nl is NULL, which makes IPsec crash because
xfrm_aevent_is_on passes the NULL pointer to netlink_has_listeners as socket.
A second problem is that the xfrm_nl pointer is not cleared when the socket
is releases at module unload time.
Protect references of xfrm_nl from outside of xfrm_user by RCU, check
that the socket is present in xfrm_aevent_is_on and set it to NULL
when unloading xfrm_user.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 7863713..61b7504 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -1001,7 +1001,15 @@
static inline int xfrm_aevent_is_on(void)
{
- return netlink_has_listeners(xfrm_nl,XFRMNLGRP_AEVENTS);
+ struct sock *nlsk;
+ int ret = 0;
+
+ rcu_read_lock();
+ nlsk = rcu_dereference(xfrm_nl);
+ if (nlsk)
+ ret = netlink_has_listeners(nlsk, XFRMNLGRP_AEVENTS);
+ rcu_read_unlock();
+ return ret;
}
static inline void xfrm_aevent_doreplay(struct xfrm_state *x)