netdev - [PATCH net 2/3] vxlan: only migrate dynamic FDB entries

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 17 Jun 2013 12:09:58 -0700
From:	Stephen Hemminger <stephen@...workplumber.org>
To:	davem@...emloft.net
Cc:	netdev@...r.kernel.org,
	Stephen Hemminger <stephen@...workplumber.org>
Subject: [PATCH net 2/3] vxlan: only migrate dynamic FDB entries

Only migrate dynamic forwarding table entries, don't modify
static entries. If packet received from incorrect source IP address
assume it is an imposter and drop it.

This patch applies only to -net, a different patch would be needed for earlier
kernels since the NTF_SELF flag was introduced with 3.10.

Signed-off-by: Stephen Hemminger <stephen@...workplumber.org>
---
 drivers/net/vxlan.c |   16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index 577a069..15a73ec 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -565,8 +565,9 @@ skip:
 
 /* Watch incoming packets to learn mapping between Ethernet address
  * and Tunnel endpoint.
+ * Return true if packet is bogus and should be droppped.
  */
-static void vxlan_snoop(struct net_device *dev,
+static bool vxlan_snoop(struct net_device *dev,
 			__be32 src_ip, const u8 *src_mac)
 {
 	struct vxlan_dev *vxlan = netdev_priv(dev);
@@ -575,7 +576,11 @@ static void vxlan_snoop(struct net_device *dev,
 	f = vxlan_find_mac(vxlan, src_mac);
 	if (likely(f)) {
 		if (likely(f->remote.remote_ip == src_ip))
-			return;
+			return false;
+
+		/* Don't migrate static entries, drop packets */
+		if (!(f->flags & NTF_SELF))
+			return true;
 
 		if (net_ratelimit())
 			netdev_info(dev,
@@ -598,6 +603,8 @@ static void vxlan_snoop(struct net_device *dev,
 					 0, NTF_SELF);
 		spin_unlock(&vxlan->hash_lock);
 	}
+
+	return false;
 }
 
 
@@ -729,8 +736,9 @@ static int vxlan_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
 			       vxlan->dev->dev_addr) == 0)
 		goto drop;
 
-	if (vxlan->flags & VXLAN_F_LEARN)
-		vxlan_snoop(skb->dev, oip->saddr, eth_hdr(skb)->h_source);
+	if ((vxlan->flags & VXLAN_F_LEARN) &&
+	    vxlan_snoop(skb->dev, oip->saddr, eth_hdr(skb)->h_source))
+		goto drop;
 
 	__skb_tunnel_rx(skb, vxlan->dev);
 	skb_reset_network_header(skb);
-- 
1.7.10.4

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html