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From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org, Denis Kirjanov <kda@linux-powerpc.org>,
        "Matteo Croce" <mcroce@redhat.com>,
        "Eric Dumazet" <edumazet@google.com>,
        "Jurgen Van Ham" <juvanham@gmail.com>,
        "David S. Miller" <davem@davemloft.net>
Date:   Fri, 24 Apr 2020 00:06:57 +0100
Message-ID: <lsq.1587683028.236720981@decadent.org.uk>
Subject: [PATCH 3.16 190/245] macvlan: use skb_reset_mac_header() in
 macvlan_queue_xmit()
In-Reply-To: <lsq.1587683027.831233700@decadent.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

3.16.83-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Eric Dumazet <edumazet@google.com>

commit 1712b2fff8c682d145c7889d2290696647d82dab upstream.

I missed the fact that macvlan_broadcast() can be used both
in RX and TX.

skb_eth_hdr() makes only sense in TX paths, so we can not
use it blindly in macvlan_broadcast()

Fixes: 96cc4b69581d ("macvlan: do not assume mac_header is set in macvlan_broadcast()")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Jurgen Van Ham <juvanham@gmail.com>
Tested-by: Matteo Croce <mcroce@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 drivers/net/macvlan.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -162,7 +162,7 @@ static void macvlan_broadcast(struct sk_
 			      struct net_device *src,
 			      enum macvlan_mode mode)
 {
-	const struct ethhdr *eth = skb_eth_hdr(skb);
+	const struct ethhdr *eth = eth_hdr(skb);
 	const struct macvlan_dev *vlan;
 	struct sk_buff *nskb;
 	unsigned int i;
@@ -345,10 +345,11 @@ static int macvlan_queue_xmit(struct sk_
 	const struct macvlan_dev *dest;
 
 	if (vlan->mode == MACVLAN_MODE_BRIDGE) {
-		const struct ethhdr *eth = (void *)skb->data;
+		const struct ethhdr *eth = skb_eth_hdr(skb);
 
 		/* send to other bridge ports directly */
 		if (is_multicast_ether_addr(eth->h_dest)) {
+			skb_reset_mac_header(skb);
 			macvlan_broadcast(skb, port, dev, MACVLAN_MODE_BRIDGE);
 			goto xmit_world;
 		}