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[3.8.y.z,extended,stable] Patch "selinux: process labeled IPsec TCP SYN-ACK packets properly in" has been added to staging queue

Message ID 1388790902-3859-1-git-send-email-kamal@canonical.com
State New
Headers show

Commit Message

Kamal Mostafa Jan. 3, 2014, 11:15 p.m. UTC
This is a note to let you know that I have just added a patch titled

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

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.16.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

From 2b86e4610d59a6dc51c13b7b386442e526d3a693 Mon Sep 17 00:00:00 2001
From: Paul Moore <pmoore@redhat.com>
Date: Thu, 19 Dec 2013 18:27:25 -0500
Subject: selinux: process labeled IPsec TCP SYN-ACK packets properly in
 selinux_ip_postroute()

commit c0828e50485932b7e019df377a6b0a8d1ebd3080 upstream.

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@gtri.gatech.edu>
[ Paul: backported to 3.4 kernel ]
Signed-off-by: Paul Moore <pmoore@redhat.com>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
 security/selinux/hooks.c | 43 ++++++++++++++++++++++++++++++++++++-------
 1 file changed, 36 insertions(+), 7 deletions(-)

--
1.8.3.2
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Patch

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 1fd031b..9e8bcf3 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -4691,22 +4691,32 @@  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
@@ -4734,6 +4744,25 @@  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;