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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,
        syzbot+e008dccab31bd3647609@syzkaller.appspotmail.com,
        syzbot+6692c72009680f7c4eb2@syzkaller.appspotmail.com
Subject: [PATCH v3] wifi: ath9k: htc_hst: free skb in ath9k_htc_rx_msg() if there is no callback function
Date:   Wed,  4 Jan 2023 15:15:58 +0300
Message-Id: <20230104121558.38969-1-pchelkin@ispras.ru>
In-Reply-To: <20230103224815.304147-1-pchelkin@ispras.ru>
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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.")
Reported-by: syzbot+e008dccab31bd3647609@syzkaller.appspotmail.com
Reported-by: syzbot+6692c72009680f7c4eb2@syzkaller.appspotmail.com
Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
---
v1->v2: added Reported-by tag
v2->v3: use 'goto invalid' instead of freeing skb in place

 drivers/net/wireless/ath/ath9k/htc_hst.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/wireless/ath/ath9k/htc_hst.c b/drivers/net/wireless/ath/ath9k/htc_hst.c
index ca05b07a45e6..0c95f6b145ff 100644
--- a/drivers/net/wireless/ath/ath9k/htc_hst.c
+++ b/drivers/net/wireless/ath/ath9k/htc_hst.c
@@ -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
+			goto invalid;
 	}
 }
 
-- 
2.34.1