linux-kernel - [PATCH 4.9 81/97] macvlan: use skb_reset_mac_header() in macvlan_queue

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Date:   Wed, 22 Jan 2020 10:29:25 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Eric Dumazet <edumazet@...gle.com>,
        Jurgen Van Ham <juvanham@...il.com>,
        Matteo Croce <mcroce@...hat.com>,
        "David S. Miller" <davem@...emloft.net>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.9 81/97] macvlan: use skb_reset_mac_header() in macvlan_queue_xmit()

From: Eric Dumazet <edumazet@...gle.com>

[ Upstream commit 1712b2fff8c682d145c7889d2290696647d82dab ]

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@...gle.com>
Reported-by: Jurgen Van Ham <juvanham@...il.com>
Tested-by: Matteo Croce <mcroce@...hat.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/net/macvlan.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -234,7 +234,7 @@ 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;
@@ -487,10 +487,11 @@ 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;
 		}