netdev - [PATCH V2 net 2/2] openvswitch: Clear the L4 portion of the key for "later" fragments.

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Date:   Mon, 26 Aug 2019 13:45:59 -0700
From:   Greg Rose <gvrose8192@...il.com>
To:     netdev@...r.kernel.org, pshelar@....org
Cc:     joe@...d.net.nz, Justin Pettit <jpettit@....org>
Subject: [PATCH V2 net 2/2] openvswitch: Clear the L4 portion of the key for "later" fragments.

From: Justin Pettit <jpettit@....org>

Only the first fragment in a datagram contains the L4 headers.  When the
Open vSwitch module parses a packet, it always sets the IP protocol
field in the key, but can only set the L4 fields on the first fragment.
The original behavior would not clear the L4 portion of the key, so
garbage values would be sent in the key for "later" fragments.  This
patch clears the L4 fields in that circumstance to prevent sending those
garbage values as part of the upcall.

Signed-off-by: Justin Pettit <jpettit@....org>
---
 net/openvswitch/flow.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/net/openvswitch/flow.c b/net/openvswitch/flow.c
index ea12ee6..22fd55f 100644
--- a/net/openvswitch/flow.c
+++ b/net/openvswitch/flow.c
@@ -560,6 +560,7 @@ static int key_extract_l3l4(struct sk_buff *skb, struct sw_flow_key *key)
 		offset = nh->frag_off & htons(IP_OFFSET);
 		if (offset) {
 			key->ip.frag = OVS_FRAG_TYPE_LATER;
+			memset(&key->tp, 0, sizeof(key->tp));
 			return 0;
 		}
 		if (nh->frag_off & htons(IP_MF) ||
@@ -677,8 +678,10 @@ static int key_extract_l3l4(struct sk_buff *skb, struct sw_flow_key *key)
 			return error;
 		}

-		if (key->ip.frag == OVS_FRAG_TYPE_LATER)
+		if (key->ip.frag == OVS_FRAG_TYPE_LATER) {
+			memset(&key->tp, 0, sizeof(key->tp));
 			return 0;
+		}
 		if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
 			key->ip.frag = OVS_FRAG_TYPE_FIRST;

-- 
1.8.3.1