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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,
        Takeshi Misawa <jeliantsurux@gmail.com>,
        Alexey Khoroshilov <khoroshilov@ispras.ru>,
        lvc-project@linuxtesting.org,
        syzbot+b68fbebe56d8362907e8@syzkaller.appspotmail.com
Subject: Re: [PATCH] wifi: ath9k: don't allow to overwrite ENDPOINT0 attributes
In-Reply-To: <20230513214146.120963-1-pchelkin@ispras.ru>
References: <20230513214146.120963-1-pchelkin@ispras.ru>
Date:   Mon, 15 May 2023 14:15:37 +0200
Message-ID: <87r0rhdc46.fsf@toke.dk>
MIME-Version: 1.0
Content-Type: text/plain
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Fedor Pchelkin <pchelkin@ispras.ru> writes:

> A bad USB device is able to construct a service connection response
> message with target endpoint being ENDPOINT0 which is reserved for
> HTC_CTRL_RSVD_SVC and should not be modified to be used for any other
> services.
>
> Reject such service connection responses.
>
> Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
>
> Fixes: fb9987d0f748 ("ath9k_htc: Support for AR9271 chipset.")
> Reported-by: syzbot+b68fbebe56d8362907e8@syzkaller.appspotmail.com
> Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
> ---
>  drivers/net/wireless/ath/ath9k/htc_hst.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/wireless/ath/ath9k/htc_hst.c b/drivers/net/wireless/ath/ath9k/htc_hst.c
> index fe62ff668f75..a15d8d80df87 100644
> --- a/drivers/net/wireless/ath/ath9k/htc_hst.c
> +++ b/drivers/net/wireless/ath/ath9k/htc_hst.c
> @@ -114,7 +114,7 @@ static void htc_process_conn_rsp(struct htc_target *target,
>  
>  	if (svc_rspmsg->status == HTC_SERVICE_SUCCESS) {
>  		epid = svc_rspmsg->endpoint_id;
> -		if (epid < 0 || epid >= ENDPOINT_MAX)
> +		if (epid <= 0 || epid >= ENDPOINT_MAX)
>  			return;

Hmm, I think we should use the ENDPOINT0 constant here, then, and maybe
add a comment above explaining that it's reserved?

-Toke