Subject: [PATCH AUTOSEL 4.19 025/205] wil6210: drop Rx multicast packets that are looped-back to STA

From: Sasha Levin <[email-masked]>
Date: Fri, 8 Nov 2019 06:34:52 -0500

From: Dedy Lansky <[email-masked]>

[ Upstream commit 9a65064abdf82934e0ed4744125f9f466f421f57 ]

Delivering a looped-back multicast packet to network stack can cause
higher layer protocols to fail like for example IPv6 DAD.
In STA mode, upon receiving Rx multicast packet, check if the source
MAC address is equal to our own MAC address and if so drop the packet.

Signed-off-by: Dedy Lansky <[email-masked]>
Signed-off-by: Maya Erez <[email-masked]>
Signed-off-by: Kalle Valo <[email-masked]>
Signed-off-by: Sasha Levin <[email-masked]>
---
 drivers/net/wireless/ath/wil6210/txrx.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/ath/wil6210/txrx.c b/drivers/net/wireless/ath/wil6210/txrx.c
index 1b1b58e0129a3..25a65ca424c84 100644
--- a/drivers/net/wireless/ath/wil6210/txrx.c
+++ b/drivers/net/wireless/ath/wil6210/txrx.c
@@ -766,7 +766,14 @@ void wil_netif_rx_any(struct sk_buff *skb, struct net_device *ndev)
 		return;
 	}
 
-	if (wdev->iftype == NL80211_IFTYPE_AP && !vif->ap_isolate) {
+	if (wdev->iftype == NL80211_IFTYPE_STATION) {
+		if (mcast && ether_addr_equal(eth->h_source, ndev->dev_addr)) {
+			/* mcast packet looped back to us */
+			rc = GRO_DROP;
+			dev_kfree_skb(skb);
+			goto stats;
+		}
+	} else if (wdev->iftype == NL80211_IFTYPE_AP && !vif->ap_isolate) {
 		if (mcast) {
 			/* send multicast frames both to higher layers in
 			 * local net stack and back to the wireless medium
-- 
2.20.1