Re: [PATCH V2 1/3] brcmfmac: Avoid possible out-of-bounds read

From: Kalle Valo <kvalo@codeaurora.org>
To: Arend van Spriel <arend.vanspriel@broadcom.com>
Cc: Kevin Cernekee <cernekee@chromium.org>,
	franky.lin@broadcom.com, brcm80211-dev-list.pdl@broadcom.com,
	linux-wireless@vger.kernel.org, mnissler@chromium.org
Subject: Re: [PATCH V2 1/3] brcmfmac: Avoid possible out-of-bounds read
Date: Tue, 12 Sep 2017 11:05:03 +0300	[thread overview]
Message-ID: <87k214ibps.fsf@kamboji.qca.qualcomm.com> (raw)
In-Reply-To: <59B793C9.2030103@broadcom.com> (Arend van Spriel's message of "Tue, 12 Sep 2017 09:59:05 +0200")

Arend van Spriel <arend.vanspriel@broadcom.com> writes:

> On 9/12/2017 9:47 AM, Kalle Valo wrote:
>> Arend van Spriel <arend.vanspriel@broadcom.com> writes:
>>
>>> On 9/12/2017 7:48 AM, Kalle Valo wrote:
>>>> Arend van Spriel <arend.vanspriel@broadcom.com> writes:
>>>>
>>>>> On 09-09-17 21:30, Kevin Cernekee wrote:
>>>>>> In brcmf_p2p_notify_rx_mgmt_p2p_probereq(), chanspec is assigned before
>>>>>> the length of rxframe is validated.  This could lead to uninitialized
>>>>>> data being accessed (but not printed).  Since we already have a
>>>>>> perfectly good endian-swapped copy of rxframe->chanspec in ch.chspec,
>>>>>> and ch.chspec is not modified by decchspec(), avoid the extra
>>>>>> assignment and use ch.chspec in the debug print.
>>>>>>
>>>>>> Suggested-by: Mattias Nissler <mnissler@chromium.org>
>>>>>> Signed-off-by: Kevin Cernekee <cernekee@chromium.org>
>>>>>> Reviewed-by: Arend van Spriel <arend.vanspriel@broadcom.com>
>>>>>> ---
>>>>>>     drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c | 3 +--
>>>>>>     1 file changed, 1 insertion(+), 2 deletions(-)
>>>>>>
>>>>>>
>>>>>> V1->V2: Clarify changelog re: whether the uninitialized data is printed.
>>>>>
>>>>> This patch and the others in this series look fine to me.
>>>>
>>>> Should these go to v4.14?
>>>
>>> I have no strong opinion. These are certainly improvements, but it
>>> does not seem an -rc fix to me. Within this series I would say patch
>>> 3/3 adds an additional sanity check in the event processing against an
>>> attack so you may consider adding just that one to v4.14
>>
>> Ok, I'll queue patch 3 to v4.14.
>>
>>> and tag it for stable, ie.:
>>>
>>> Cc: stable@vger.kernel.org # v3.8.x
>>
>> But why v3.8.x? I admit that I haven't fully figured out the stable tags
>> yet, but doesn't that mean that it will be only applied to v3.8.x and
>> nothing else? I was expecting it to be:
>>
>> Cc: stable@vger.kernel.org # v3.8+
>>
>
> It is actually in the stable-kernel-rules documentation [1]:
>
> """
> Also, some patches may have kernel version prerequisites.  This can be
> specified in the following format in the sign-off area:
>
> .. code-block:: none
>
>      Cc: <stable@vger.kernel.org> # 3.3.x
>
> The tag has the meaning of:
>
> .. code-block:: none
>
>      git cherry-pick <this commit>
>
> For each "-stable" tree starting with the specified version.
> """

Yeah, but it says "starting with" which I interpret as "starting with
string '3.3'". For example the commit here would be applied to 3.3.1,
3.3.2 and 3.3.3 etc but _not_ to 3.4, 3.4.1, 3.5 or any later release.

Of course I can be way off here, wouldn't be the first :)

-- 
Kalle Valo