[PATCH stable 2/2] Resubmitting to stable as a backport, backported based on the 3.4 stable

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queue but should apply to the other stable kernels >=3.4.

Original commit description is shown below.

	commit c0828e50485932b7e019df377a6b0a8d1ebd3080
	Author: Paul Moore <pmoore@xxxxxxxxxx>
	Date:   Tue Dec 10 14:58:01 2013 -0500

	selinux: process labeled IPsec TCP SYN-ACK packets properly in selinux_ip_postroute()

	Due to difficulty in arriving at the proper security label for
	TCP SYN-ACK packets in selinux_ip_postroute(), we need to check packets
	while/before they are undergoing XFRM transforms instead of waiting
	until afterwards so that we can determine the correct security label.

	Reported-by: Janak Desai <Janak.Desai@xxxxxxxxxxxxxxx>
	Cc: stable@xxxxxxxxxxxxxxx
	Signed-off-by: Paul Moore <pmoore@xxxxxxxxxx>
---
 security/selinux/hooks.c |   43 ++++++++++++++++++++++++++++++++++++-------
 1 file changed, 36 insertions(+), 7 deletions(-)

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 96e64e9..1f13d2b 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -4727,22 +4727,32 @@ static unsigned int selinux_ip_postroute(struct sk_buff *skb, int ifindex,
 	 * as fast and as clean as possible. */
 	if (!selinux_policycap_netpeer)
 		return selinux_ip_postroute_compat(skb, ifindex, family);
+
+	secmark_active = selinux_secmark_enabled();
+	peerlbl_active = netlbl_enabled() || selinux_xfrm_enabled();
+	if (!secmark_active && !peerlbl_active)
+		return NF_ACCEPT;
+
+	sk = skb->sk;
+
 #ifdef CONFIG_XFRM
 	/* If skb->dst->xfrm is non-NULL then the packet is undergoing an IPsec
 	 * packet transformation so allow the packet to pass without any checks
 	 * since we'll have another chance to perform access control checks
 	 * when the packet is on it's final way out.
 	 * NOTE: there appear to be some IPv6 multicast cases where skb->dst
-	 *       is NULL, in this case go ahead and apply access control. */
-	if (skb_dst(skb) != NULL && skb_dst(skb)->xfrm != NULL)
+	 *       is NULL, in this case go ahead and apply access control.
+	 *       is NULL, in this case go ahead and apply access control.
+	 * NOTE: if this is a local socket (skb->sk != NULL) that is in the
+	 *       TCP listening state we cannot wait until the XFRM processing
+	 *       is done as we will miss out on the SA label if we do;
+	 *       unfortunately, this means more work, but it is only once per
+	 *       connection. */
+	if (skb_dst(skb) != NULL && skb_dst(skb)->xfrm != NULL &&
+	    !(sk != NULL && sk->sk_state == TCP_LISTEN))
 		return NF_ACCEPT;
 #endif
-	secmark_active = selinux_secmark_enabled();
-	peerlbl_active = netlbl_enabled() || selinux_xfrm_enabled();
-	if (!secmark_active && !peerlbl_active)
-		return NF_ACCEPT;
 
-	sk = skb->sk;
 	if (sk == NULL) {
 		/* Without an associated socket the packet is either coming
 		 * from the kernel or it is being forwarded; check the packet
@@ -4770,6 +4780,25 @@ static unsigned int selinux_ip_postroute(struct sk_buff *skb, int ifindex,
 		struct sk_security_struct *sksec = sk->sk_security;
 		if (selinux_skb_peerlbl_sid(skb, family, &skb_sid))
 			return NF_DROP;
+		/* At this point, if the returned skb peerlbl is SECSID_NULL
+		 * and the packet has been through at least one XFRM
+		 * transformation then we must be dealing with the "final"
+		 * form of labeled IPsec packet; since we've already applied
+		 * all of our access controls on this packet we can safely
+		 * pass the packet. */
+		if (skb_sid == SECSID_NULL) {
+			switch (family) {
+			case PF_INET:
+				if (IPCB(skb)->flags & IPSKB_XFRM_TRANSFORMED)
+					return NF_ACCEPT;
+				break;
+			case PF_INET6:
+				if (IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED)
+					return NF_ACCEPT;
+			default:
+				return NF_DROP_ERR(-ECONNREFUSED);
+			}
+		}
 		if (selinux_conn_sid(sksec->sid, skb_sid, &peer_sid))
 			return NF_DROP;
 		secmark_perm = PACKET__SEND;

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