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SubjectRe: [PATCH] Revert "ath9k: fix ath_tx_process_buffer() potential null ptr dereference"
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On 2/17/21 11:23 PM, Kalle Valo wrote:
> Shuah Khan <skhan@linuxfoundation.org> wrote:
>
>> This reverts commit a56c14bb21b296fb6d395164ab62ef2e419e5069.
>>
>> ath_tx_process_buffer() doesn't dereference or check sta and passes it
>> to ath_tx_complete_aggr() and ath_tx_complete_buf().
>>
>> ath_tx_complete_aggr() checks the pointer before use. No problem here.
>>
>> ath_tx_complete_buf() doesn't check or dereference sta and passes it on
>> to ath_tx_complete(). ath_tx_complete() doesn't check or dereference sta,
>> but assigns it to tx_info->status.status_driver_data[0]
>>
>> ath_tx_complete_buf() is called from ath_tx_complete_aggr() passing
>> null ieee80211_sta pointer.
>>
>> There is a potential for dereference later on, if and when the
>> tx_info->status.status_driver_data[0]is referenced. In addition, the
>> rcu read lock might be released before referencing the contents.
>>
>> ath_tx_complete_buf() should be fixed to check sta perhaps? Worth
>> looking into.
>>
>> Reverting this patch because it doesn't solve the problem and introduces
>> memory leak by skipping buffer completion if the pointer (sta) is NULL.
>>
>> Fixes: a56c14bb21b2 ("ath9k: fix ath_tx_process_buffer() potential null ptr dereference")
>> Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
>> Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
>
> Thanks. I added the commit id and Fixes tag to the commit log, see the new version above.
>

Thanks. Sorry for forgetting the Fixes tag.

thanks,
-- Shuah

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