linux-kernel - [PATCH 4.4 188/312] flow_dissector: Check for IP fragmentation even if not using IPv4 address

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Date:   Fri,  8 May 2020 14:32:59 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Alexander Duyck <aduyck@...antis.com>,
        Tom Herbert <tom@...bertland.com>,
        "David S. Miller" <davem@...emloft.net>
Subject: [PATCH 4.4 188/312] flow_dissector: Check for IP fragmentation even if not using IPv4 address

From: Alexander Duyck <aduyck@...antis.com>

commit 918c023f29ab2dd8c63cfcc6a1239ee15933871a upstream.

This patch corrects the logic for the IPv4 parsing so that it is consistent
with how we handle IPv6.  Specifically if we do not have the flow key
indicating we want the addresses we still may need to take a look at the IP
fragmentation bits and to see if we should stop after we have recognized
the L3 header.

Fixes: 807e165dc44f ("flow_dissector: Add control/reporting of fragmentation")
Signed-off-by: Alexander Duyck <aduyck@...antis.com>
Acked-by: Tom Herbert <tom@...bertland.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 net/core/flow_dissector.c |   17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -178,15 +178,16 @@ ip:
 
 		ip_proto = iph->protocol;
 
-		if (!dissector_uses_key(flow_dissector,
-					FLOW_DISSECTOR_KEY_IPV4_ADDRS))
-			break;
+		if (dissector_uses_key(flow_dissector,
+				       FLOW_DISSECTOR_KEY_IPV4_ADDRS)) {
+			key_addrs = skb_flow_dissector_target(flow_dissector,
+							      FLOW_DISSECTOR_KEY_IPV4_ADDRS,
+							      target_container);
 
-		key_addrs = skb_flow_dissector_target(flow_dissector,
-			      FLOW_DISSECTOR_KEY_IPV4_ADDRS, target_container);
-		memcpy(&key_addrs->v4addrs, &iph->saddr,
-		       sizeof(key_addrs->v4addrs));
-		key_control->addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
+			memcpy(&key_addrs->v4addrs, &iph->saddr,
+			       sizeof(key_addrs->v4addrs));
+			key_control->addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
+		}
 
 		if (ip_is_fragment(iph)) {
 			key_control->flags |= FLOW_DIS_IS_FRAGMENT;