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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, Bitterblue Smith <rtl8821cerfe2@gmail.com>,
        Kalle Valo <kvalo@kernel.org>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.14 087/210] wifi: rtl8xxxu: Fix skb misuse in TX queue selection
Date:   Mon, 24 Oct 2022 13:30:04 +0200
Message-Id: <20221024112959.871050235@linuxfoundation.org>
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From: Bitterblue Smith <rtl8821cerfe2@gmail.com>

[ Upstream commit edd5747aa12ed61a5ecbfa58d3908623fddbf1e8 ]

rtl8xxxu_queue_select() selects the wrong TX queues because it's
reading memory from the wrong address. It expects to find ieee80211_hdr
at skb->data, but that's not the case after skb_push(). Move the call
to rtl8xxxu_queue_select() before the call to skb_push().

Fixes: 26f1fad29ad9 ("New driver: rtl8xxxu (mac80211)")
Signed-off-by: Bitterblue Smith <rtl8821cerfe2@gmail.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/7fa4819a-4f20-b2af-b7a6-8ee01ac49295@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
index 5588518daa96..7cace68ef3c7 100644
--- a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
+++ b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
@@ -4955,6 +4955,8 @@ static void rtl8xxxu_tx(struct ieee80211_hw *hw,
 	if (control && control->sta)
 		sta = control->sta;
 
+	queue = rtl8xxxu_queue_select(hw, skb);
+
 	tx_desc = skb_push(skb, tx_desc_size);
 
 	memset(tx_desc, 0, tx_desc_size);
@@ -4967,7 +4969,6 @@ static void rtl8xxxu_tx(struct ieee80211_hw *hw,
 	    is_broadcast_ether_addr(ieee80211_get_DA(hdr)))
 		tx_desc->txdw0 |= TXDESC_BROADMULTICAST;
 
-	queue = rtl8xxxu_queue_select(hw, skb);
 	tx_desc->txdw1 = cpu_to_le32(queue << TXDESC_QUEUE_SHIFT);
 
 	if (tx_info->control.hw_key) {
-- 
2.35.1