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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        =?UTF-8?q?Thibaut=20VAR=C3=88NE?= <hacks+kernel@slashdirt.org>,
        Felix Fietkau <nbd@nbd.name>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.18 161/879] mt76: fix encap offload ethernet type check
Date:   Tue,  7 Jun 2022 18:54:39 +0200
Message-Id: <20220607165007.379568253@linuxfoundation.org>
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From: Felix Fietkau <nbd@nbd.name>

[ Upstream commit bc98e7fdd80d215b4b55eea001023231eb8ce12e ]

The driver needs to check if the format is 802.2 vs 802.3 in order to set
a tx descriptor flag. skb->protocol can't be used, since it may not be properly
initialized for packets coming in from a packet socket.
Fix misdetection by checking the ethertype from the skb data instead

Reported-by: Thibaut VARÈNE <hacks+kernel@slashdirt.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/wireless/mediatek/mt76/mt7915/mac.c | 4 +++-
 drivers/net/wireless/mediatek/mt76/mt7921/mac.c | 4 +++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/mac.c b/drivers/net/wireless/mediatek/mt76/mt7915/mac.c
index a8df65cc115f..eaa31f5e0b00 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7915/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7915/mac.c
@@ -1017,6 +1017,7 @@ mt7915_mac_write_txwi_8023(struct mt7915_dev *dev, __le32 *txwi,
 
 	u8 tid = skb->priority & IEEE80211_QOS_CTL_TID_MASK;
 	u8 fc_type, fc_stype;
+	u16 ethertype;
 	bool wmm = false;
 	u32 val;
 
@@ -1030,7 +1031,8 @@ mt7915_mac_write_txwi_8023(struct mt7915_dev *dev, __le32 *txwi,
 	val = FIELD_PREP(MT_TXD1_HDR_FORMAT, MT_HDR_FORMAT_802_3) |
 	      FIELD_PREP(MT_TXD1_TID, tid);
 
-	if (be16_to_cpu(skb->protocol) >= ETH_P_802_3_MIN)
+	ethertype = get_unaligned_be16(&skb->data[12]);
+	if (ethertype >= ETH_P_802_3_MIN)
 		val |= MT_TXD1_ETH_802_3;
 
 	txwi[1] |= cpu_to_le32(val);
diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/mac.c b/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
index f34070ca7bbe..c5350e7a11e6 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
@@ -814,6 +814,7 @@ mt7921_mac_write_txwi_8023(struct mt7921_dev *dev, __le32 *txwi,
 {
 	u8 tid = skb->priority & IEEE80211_QOS_CTL_TID_MASK;
 	u8 fc_type, fc_stype;
+	u16 ethertype;
 	bool wmm = false;
 	u32 val;
 
@@ -827,7 +828,8 @@ mt7921_mac_write_txwi_8023(struct mt7921_dev *dev, __le32 *txwi,
 	val = FIELD_PREP(MT_TXD1_HDR_FORMAT, MT_HDR_FORMAT_802_3) |
 	      FIELD_PREP(MT_TXD1_TID, tid);
 
-	if (be16_to_cpu(skb->protocol) >= ETH_P_802_3_MIN)
+	ethertype = get_unaligned_be16(&skb->data[12]);
+	if (ethertype >= ETH_P_802_3_MIN)
 		val |= MT_TXD1_ETH_802_3;
 
 	txwi[1] |= cpu_to_le32(val);
-- 
2.35.1