[ovs-dev] [PATCH v3 23/28] datapath: backport: udp: prevent skbs lingering in tunnel socket queues

[Pravin B Shelar]

Upstream commit:
    commit e5aed006be918af163eb397e45aa5ea6cefd5e01
    Author: Hannes Frederic Sowa <hannes at stressinduktion.org>

    udp: prevent skbs lingering in tunnel socket queues

    In case we find a socket with encapsulation enabled we should call
    the encap_recv function even if just a udp header without payload is
    available. The callbacks are responsible for correctly verifying and
    dropping the packets.

    Also, in case the header validation fails for geneve and vxlan we
    shouldn't put the skb back into the socket queue, no one will pick
    them up there.  Instead we can simply discard them in the respective
    encap_recv functions.

    Signed-off-by: Hannes Frederic Sowa <hannes at stressinduktion.org>
    Signed-off-by: David S. Miller <davem at davemloft.net>

Signed-off-by: Pravin B Shelar <pshelar at ovn.org>
Acked-by: Jesse Gross <jesse at kernel.org>
---
 datapath/linux/compat/geneve.c | 10 +++-------
 datapath/linux/compat/vxlan.c  |  4 ++--
 2 files changed, 5 insertions(+), 9 deletions(-)

diff --git a/datapath/linux/compat/geneve.c b/datapath/linux/compat/geneve.c
index 6e1b759..6dff655 100644
--- a/datapath/linux/compat/geneve.c
+++ b/datapath/linux/compat/geneve.c
@@ -337,15 +337,15 @@ static int geneve_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
 
 	/* Need Geneve and inner Ethernet header to be present */
 	if (unlikely(!pskb_may_pull(skb, GENEVE_BASE_HLEN)))
-		goto error;
+		goto drop;
 
 	/* Return packets with reserved bits set */
 	geneveh = geneve_hdr(skb);
 	if (unlikely(geneveh->ver != GENEVE_VER))
-		goto error;
+		goto drop;
 
 	if (unlikely(geneveh->proto_type != htons(ETH_P_TEB)))
-		goto error;
+		goto drop;
 
 	gs = rcu_dereference_sk_user_data(sk);
 	if (!gs)
@@ -368,10 +368,6 @@ drop:
 	/* Consume bad packet */
 	kfree_skb(skb);
 	return 0;
-
-error:
-	/* Let the UDP layer deal with the skb */
-	return 1;
 }
 
 static struct socket *geneve_create_sock(struct net *net, bool ipv6,
diff --git a/datapath/linux/compat/vxlan.c b/datapath/linux/compat/vxlan.c
index ca33358..827f3e3 100644
--- a/datapath/linux/compat/vxlan.c
+++ b/datapath/linux/compat/vxlan.c
@@ -667,7 +667,7 @@ static int vxlan_rcv(struct sock *sk, struct sk_buff *skb)
 
 	/* Need UDP and VXLAN header to be present */
 	if (!pskb_may_pull(skb, VXLAN_HLEN))
-		return 1;
+		goto drop;
 
 	unparsed = *vxlan_hdr(skb);
 	/* VNI flag always required to be set */
@@ -676,7 +676,7 @@ static int vxlan_rcv(struct sock *sk, struct sk_buff *skb)
 			   ntohl(vxlan_hdr(skb)->vx_flags),
 			   ntohl(vxlan_hdr(skb)->vx_vni));
 		/* Return non vxlan pkt */
-		return 1;
+		goto drop;
 	}
 	unparsed.vx_flags &= ~VXLAN_HF_VNI;
 	unparsed.vx_vni &= ~VXLAN_VNI_MASK;
-- 
1.9.1