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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: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Patrick McHardy 2006-03-20 22:40:54 -08:00 committed by David S. Miller
parent 15d99e02ba
commit be33690d8f
2 changed files with 20 additions and 5 deletions
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10
include/net/xfrm.h
View File

@ -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)

15
net/xfrm/xfrm_user.c
View File

@ -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,
xfrm_netlink_rcv, THIS_MODULE);
if (xfrm_nl == NULL)
nlsk = netlink_kernel_create(NETLINK_XFRM, XFRMNLGRP_MAX,
xfrm_netlink_rcv, THIS_MODULE);
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);