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Sender: Guenter Roeck <groeck7@gmail.com>
Message-ID: <065cf0e5-2c64-56c6-ee66-a6b61be2dddf@roeck-us.net>
Date:   Mon, 9 Jan 2023 07:43:15 -0800
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Subject: Re: [PATCH] wifi: mac80211: change initialize for sk_buff in
 ieee80211_tx_dequeue()
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To:     Alexander Wetzel <alexander@wetzel-home.de>,
        Wen Gong <quic_wgong@quicinc.com>
Cc:     johannes@sipsolutions.net, ath11k@lists.infradead.org,
        linux-wireless@vger.kernel.org
References: <20221212083607.21536-1-quic_wgong@quicinc.com>
 <20230105052647.GA2477583@roeck-us.net>
 <d28c6340-7ad2-d7f6-939d-3a1a057cb7da@wetzel-home.de>
 <3372b42f-b9bf-20e8-35f9-5370571a9e35@wetzel-home.de>
From:   Guenter Roeck <linux@roeck-us.net>
In-Reply-To: <3372b42f-b9bf-20e8-35f9-5370571a9e35@wetzel-home.de>
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On 1/9/23 06:22, Alexander Wetzel wrote:
> On 09.01.23 15:05, Alexander Wetzel wrote:
>> On 05.01.23 06:26, Guenter Roeck wrote:
>>> On Mon, Dec 12, 2022 at 03:36:07AM -0500, Wen Gong wrote:
>>>> The sk_buff is only set to NULL when initialize, sometimes it will goto
>>>> label "begin" after ieee80211_free_txskb(), then it points to a sk_buff
>>>> which is already freed. If it run into the "goto out" after arrived to
>>>> label "begin", then it will return a sk_buff which is freed, it is a
>>>> risk for use-after-free.
>>>>
>>>> Fixes: ded4698b58cb ("mac80211: run late dequeue late tx handlers without holding fq->lock")
>>>> Signed-off-by: Wen Gong <quic_wgong@quicinc.com>
>>>
>>> I don't see any progress on this patch. Is there a problem with it ?
>>> Did it get lost ?
>>>
>>
>> Looks ok for me. But I just noticed that my patch
>> https://patchwork.kernel.org/project/linux-wireless/patch/20221230121850.218810-1-alexander@wetzel-home.de/
>>
>> should also fix the issue as an unintended side effect.
> 
> Sorry that statement was incomplete: It's only fixed when
> https://patchwork.kernel.org/project/linux-wireless/patch/20221230121850.218810-1-alexander@wetzel-home.de/
> and
> https://patchwork.kernel.org/project/linux-wireless/patch/20230106223141.98696-1-alexander@wetzel-home.de/
> 
> are applied.
> 

Ah, yes. That is indeed correct. Let's just hope those patches will apply (and are
going to be applied) to stable releases since this is a real problem there which
does cause UAF and crashes.

Guenter