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Commit be33690d authored by Patrick McHardy's avatar Patrick McHardy Committed by David S. Miller
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[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: default avatarPatrick McHardy <kaber@trash.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 15d99e02

include/net/xfrm.h

+9 −1
Original line number Diff line number Diff line
@@ -1001,7 +1001,15 @@ static inline int xfrm_policy_id2dir(u32 index) 


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)

net/xfrm/xfrm_user.c

+11 −4
Original line number Diff line number Diff line
@@ -1947,12 +1947,15 @@ static struct xfrm_mgr netlink_mgr = { 


static int __init xfrm_user_init(void)

{

	struct sock *nlsk;



	printk(KERN_INFO "Initializing IPsec netlink socket\n");



	xfrm_nl = netlink_kernel_create(NETLINK_XFRM, XFRMNLGRP_MAX,

	nlsk = netlink_kernel_create(NETLINK_XFRM, XFRMNLGRP_MAX,

	                             xfrm_netlink_rcv, THIS_MODULE);

	if (xfrm_nl == NULL)

	if (nlsk == NULL)

		return -ENOMEM;

	rcu_assign_pointer(xfrm_nl, nlsk);



	xfrm_register_km(&netlink_mgr);
@@ -1961,8 +1964,12 @@ static int __init xfrm_user_init(void) 


static void __exit xfrm_user_exit(void)

{

	struct sock *nlsk = xfrm_nl;



	xfrm_unregister_km(&netlink_mgr);

	sock_release(xfrm_nl->sk_socket);

	rcu_assign_pointer(xfrm_nl, NULL);

	synchronize_rcu();

	sock_release(nlsk->sk_socket);

}



module_init(xfrm_user_init);