[PATCH] wifi: mac80211: change initialize for sk_buff in ieee80211_tx_dequeue()

[Guenter Roeck]

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 at 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