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Message-ID: <1e1f0cc1-d4ae-c536-4ffc-256a0fd3a265@rempel-privat.de>
Date:   Mon, 11 Apr 2022 12:24:02 +0200
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Subject: Re: [PATCH] ath9k_htc: fix potential out of bounds access with
 invalid rxstatus->rs_keyix
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To:     Dan Carpenter <dan.carpenter@oracle.com>
Cc:     =?UTF-8?Q?Toke_H=c3=b8iland-J=c3=b8rgensen?= <toke@toke.dk>,
        Kalle Valo <kvalo@kernel.org>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        "John W. Linville" <linville@tuxdriver.com>,
        linux-wireless@vger.kernel.org, kernel-janitors@vger.kernel.org
References: <20220409061225.GA5447@kili>
 <00a0f9f7-2fbf-8883-38e7-edec3687e6a8@rempel-privat.de>
 <20220411075403.GZ12805@kadam>
From:   Oleksij Rempel <linux@rempel-privat.de>
In-Reply-To: <20220411075403.GZ12805@kadam>
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Am 11.04.22 um 09:54 schrieb Dan Carpenter:
> On Sat, Apr 09, 2022 at 09:53:53AM +0200, Oleksij Rempel wrote:
>>> diff --git a/drivers/net/wireless/ath/ath9k/htc_drv_txrx.c b/drivers/n=
et/wireless/ath/ath9k/htc_drv_txrx.c
>>> index 6a850a0bfa8a..a23eaca0326d 100644
>>> --- a/drivers/net/wireless/ath/ath9k/htc_drv_txrx.c
>>> +++ b/drivers/net/wireless/ath/ath9k/htc_drv_txrx.c
>>> @@ -1016,6 +1016,14 @@ static bool ath9k_rx_prepare(struct ath9k_htc_p=
riv *priv,
>>>    		goto rx_next;
>>>    	}
>>>
>>> +	if (rxstatus->rs_keyix >=3D ATH_KEYMAX &&
>>> +	    rxstatus->rs_keyix !=3D ATH9K_RXKEYIX_INVALID) {
>>> +		ath_dbg(common, ANY,
>>> +			"Invalid keyix, dropping (keyix: %d)\n",
>>> +			rxstatus->rs_keyix);
>>> +		goto rx_next;
>>> +	}
>>> +
>>>    	/* Get the RX status information */
>>>
>>>    	memset(rx_status, 0, sizeof(struct ieee80211_rx_status));
>>
>> Looks ok to me.
>
> Thanks!
>
>>
>> By the way, rs_keyix seems to have a wrong type. It is declared as u8, =
but used as s8.
>
> That sounds like something outside the scope of the patch...

ack :)

> Why do you mean "used as s8"?  Which function are you talking about?
>
> You made me panic briefly because ATH9K_RXKEYIX_INVALID is a u8 so it
> needs to be u8.  I would have thought instinctively that u8 would be the
> right type for an index like this.

Because ATH_KEYMAX =3D=3D S8_MAX and ATH9K_RXKEYIX_INVALID is ((u8)-1)

All bitmap values within drivers/net/wireless/ath should never have BIT(7)=
 set, except it is -1.

=2D-
Regards,
Oleksij