selinux: look for IPsec labels on both inbound and outbound packets

commit 817eff718dca4e54d5721211ddde0914428fbb7c upstream.

Previously selinux_skb_peerlbl_sid() would only check for labeled
IPsec security labels on inbound packets, this patch enables it to
check both inbound and outbound traffic for labeled IPsec security
labels.

Reported-by: Janak Desai <Janak.Desai@gtri.gatech.edu>
Signed-off-by: Paul Moore <pmoore@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/security/selinux/include/xfrm.h b/security/selinux/include/xfrm.h
index c220f31..d1c980c 100644
--- a/security/selinux/include/xfrm.h
+++ b/security/selinux/include/xfrm.h
@@ -47,6 +47,7 @@
 int selinux_xfrm_postroute_last(u32 isec_sid, struct sk_buff *skb,
 			struct common_audit_data *ad, u8 proto);
 int selinux_xfrm_decode_session(struct sk_buff *skb, u32 *sid, int ckall);
+int selinux_xfrm_skb_sid(struct sk_buff *skb, u32 *sid);
 
 static inline void selinux_xfrm_notify_policyload(void)
 {
@@ -79,12 +80,12 @@
 static inline void selinux_xfrm_notify_policyload(void)
 {
 }
-#endif
 
-static inline void selinux_skb_xfrm_sid(struct sk_buff *skb, u32 *sid)
+static inline int selinux_xfrm_skb_sid(struct sk_buff *skb, u32 *sid)
 {
-	int err = selinux_xfrm_decode_session(skb, sid, 0);
-	BUG_ON(err);
+	*sid = SECSID_NULL;
+	return 0;
 }
+#endif
 
 #endif /* _SELINUX_XFRM_H_ */