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From:   Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= <toke@toke.dk>
To:     Fedor Pchelkin <pchelkin@ispras.ru>, 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>,
        linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Alexey Khoroshilov <khoroshilov@ispras.ru>,
        lvc-project@linuxtesting.org
Subject: Re: [PATCH v2] ath9k: hif_usb: Fix use-after-free in
 ath9k_hif_usb_reg_in_cb()
In-Reply-To: <20221008114917.21404-1-pchelkin@ispras.ru>
References: <20221008114917.21404-1-pchelkin@ispras.ru>
Date:   Sun, 09 Oct 2022 00:36:05 +0200
Message-ID: <87pmf2rlii.fsf@toke.dk>
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Fedor Pchelkin <pchelkin@ispras.ru> writes:

> It is possible that skb is freed in ath9k_htc_rx_msg(), then
> usb_submit_urb() fails and we try to free skb again. It causes
> use-after-free bug. Moreover, if alloc_skb() fails, urb->context becomes
> NULL but rx_buf is not freed and there can be a memory leak.
>
> The patch removes unnecessary nskb and makes skb processing more clear: it
> is supposed that ath9k_htc_rx_msg() either frees old skb or passes its
> managing to another callback function.
>
> Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
>
> Fixes: 3deff76095c4 ("ath9k_htc: Increase URB count for REG_IN pipe")
> Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
> Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>

Acked-by: Toke H=C3=B8iland-J=C3=B8rgensen <toke@toke.dk>