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From:   Fedor Pchelkin <pchelkin@ispras.ru>
To:     =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= <toke@toke.dk>,
        Kalle Valo <kvalo@kernel.org>
Cc:     Fedor Pchelkin <pchelkin@ispras.ru>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Sujith <Sujith.Manoharan@atheros.com>,
        "John W. Linville" <linville@tuxdriver.com>,
        Vasanthakumar Thiagarajan <vasanth@atheros.com>,
        Senthil Balasubramanian <senthilkumar@atheros.com>,
        linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Alexey Khoroshilov <khoroshilov@ispras.ru>,
        lvc-project@linuxtesting.org
Subject: [PATCH] wifi: ath9k: htc_hst: free skb in ath9k_htc_rx_msg() if there is no callback function
Date:   Thu, 29 Dec 2022 01:40:47 +0300
Message-Id: <20221228224047.146399-1-pchelkin@ispras.ru>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

It is stated that ath9k_htc_rx_msg() either frees the provided skb or
passes its management to another callback function. However, the skb is
not freed in case there is no another callback function, and Syzkaller was
able to cause a memory leak. Also minor comment fix.

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Fixes: fb9987d0f748 ("ath9k_htc: Support for AR9271 chipset.")
Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
---
 drivers/net/wireless/ath/ath9k/htc_hst.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/ath/ath9k/htc_hst.c b/drivers/net/wireless/ath/ath9k/htc_hst.c
index ca05b07a45e6..7d5041eb5f29 100644
--- a/drivers/net/wireless/ath/ath9k/htc_hst.c
+++ b/drivers/net/wireless/ath/ath9k/htc_hst.c
@@ -391,7 +391,7 @@ static void ath9k_htc_fw_panic_report(struct htc_target *htc_handle,
  * HTC Messages are handled directly here and the obtained SKB
  * is freed.
  *
- * Service messages (Data, WMI) passed to the corresponding
+ * Service messages (Data, WMI) are passed to the corresponding
  * endpoint RX handlers, which have to free the SKB.
  */
 void ath9k_htc_rx_msg(struct htc_target *htc_handle,
@@ -478,6 +478,8 @@ void ath9k_htc_rx_msg(struct htc_target *htc_handle,
 		if (endpoint->ep_callbacks.rx)
 			endpoint->ep_callbacks.rx(endpoint->ep_callbacks.priv,
 						  skb, epid);
+		else
+			kfree_skb(skb);
 	}
 }
 
-- 
2.34.1