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From:   Ming Chen <ming032217@gmail.com>
To:     Johannes Berg <johannes@sipsolutions.net>
Cc:     linux-wireless@vger.kernel.org,
        Ming Chen <ming.chen@watchguard.com>
Subject: [PATCH v2] mac80211: Drop the packets whose source or destination mac address is empty
Date:   Thu, 14 Nov 2019 11:57:12 -0800
Message-Id: <20191114195712.101568-1-ming.chen@watchguard.com>
Sender: linux-wireless-owner@vger.kernel.org
Precedence: bulk

We occasionally found ath9k could receive some packets from Linux IP stack
with empty source and destination mac address,which will result in the
driver cannot find the station node in TX complete. And thus, the driver
will complete this buffer but without updating the block ack window.

To fix this issue, we should drop this kind of error packet before it
goes into the driver.
---

According to review feedback, use the is_zero_ether_addr to check if the
mac address is empty.

Signed-off-by: Ming Chen <ming.chen@watchguard.com>
---
 net/mac80211/tx.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index db38be1b75fa..b18745a3f6b0 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -2489,6 +2489,13 @@ static struct sk_buff *ieee80211_build_hdr(struct ieee80211_sub_if_data *sdata,
 	if (IS_ERR(sta))
 		sta = NULL;
 
+	/* drop this skb when source mac or destination mac is empty */
+	if (is_zero_ether_addr(skb->data) ||
+	    is_zero_ether_addr(skb->data + ETH_ALEN)) {
+		ret = -ENOTCONN;
+		goto free;
+	}
+
 #ifdef CONFIG_MAC80211_DEBUGFS
 	if (local->force_tx_status)
 		info_flags |= IEEE80211_TX_CTL_REQ_TX_STATUS;
@@ -3435,6 +3442,11 @@ static bool ieee80211_xmit_fast(struct ieee80211_sub_if_data *sdata,
 	if (skb->sk && skb_shinfo(skb)->tx_flags & SKBTX_WIFI_STATUS)
 		return false;
 
+	/* drop this skb when source mac or destination mac is empty */
+	if (is_zero_ether_addr(skb->data) ||
+	    is_zero_ether_addr(skb->data + ETH_ALEN))
+		return false;
+
 	if (hdr->frame_control & cpu_to_le16(IEEE80211_STYPE_QOS_DATA)) {
 		tid = skb->priority & IEEE80211_QOS_CTL_TAG1D_MASK;
 		tid_tx = rcu_dereference(sta->ampdu_mlme.tid_tx[tid]);
-- 
2.17.1