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

From: Arend van Spriel <arend.vanspriel@broadcom.com>
To: Kalle Valo <kvalo@codeaurora.org>
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 09:59:05 +0200	[thread overview]
Message-ID: <59B793C9.2030103@broadcom.com> (raw)
In-Reply-To: <87o9qgicju.fsf@kamboji.qca.qualcomm.com>

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.
"""

The event handling code was added in v3.8.

Regards,
Arend

[1] https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html