netdev - Re: [PATCH] brcm80211: brcmfmac: Ensure that incoming skb's are writable

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Message-ID: <60f9d8a0-e8b5-ef05-ea78-caacfcf0ae67@broadcom.com>
Date:   Thu, 20 Apr 2017 21:13:39 +0200
From:   Arend van Spriel <arend.vanspriel@...adcom.com>
To:     James Hughes <james.hughes@...pberrypi.org>,
        Kalle Valo <kvalo@...eaurora.org>
Cc:     netdev@...r.kernel.org, Franky Lin <franky.lin@...adcom.com>,
        Hante Meuleman <hante.meuleman@...adcom.com>,
        linux-wireless@...r.kernel.org
Subject: Re: [PATCH] brcm80211: brcmfmac: Ensure that incoming skb's are
 writable

On 4/20/2017 2:09 PM, James Hughes wrote:
> On 20 April 2017 at 12:31, Kalle Valo <kvalo@...eaurora.org> wrote:
>> + linux-wireless
>>
>> James Hughes <james.hughes@...pberrypi.org> writes:
>>
>>> The driver was adding header information to incoming skb
>>> without ensuring the head was uncloned and hence writable.
>>>
>>> skb_cow_head has been used to ensure they are writable, however,
>>> this required some changes to error handling to ensure that
>>> if skb_cow_head failed it was not ignored.
>>>
>>> This really needs to be reviewed by someone who is more familiar
>>> with this code base to ensure any deallocation of skb's is
>>> still correct.
>>>
>>> Signed-off-by: James Hughes <james.hughes@...pberrypi.org>
>>
>> You should also CC linux-wireless, otherwise patchwork won't see it.
>>
>> --
>> Kalle Valo
> 
> Thanks Kalle, I wasn't subscribed to wireless, but have now done so. I
> also failed to read the MAINTAINERS list correctly..
> 
> With regard to this particular patch, this is related to the recent
> patches to use skb_cow_head in a number of USB net drivers to ensure
> they can write headers correctly, and I suspect the same fault is
> possible/likely in other drivers outside the USB net realm, as this
> patch shows.
> 
> I'm not overly happy with the error handling in this patch, but that
> said, the error handling over this entire driver does strike me as
> suspect. Quite a few places where return codes are ignored, just in my
> quick examination. So not really sure how to proceed past this patch,
> if at all.

I would appreciate it if you can provide details about the code you 
consider suspect. I will respond on the patches soon.

Regards,
Arend