netdev - Re: [Patch net] gre: refetch erspan header from skb->data after pskb_may

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Message-ID: <CALDO+SbGB2DmSQ-FzLCvNvU+nvHmbxpoNeyZHOwJbgbha6EZwg@mail.gmail.com>
Date:   Fri, 6 Dec 2019 09:08:44 -0800
From:   William Tu <u9012063@...il.com>
To:     Lorenzo Bianconi <lorenzo.bianconi@...hat.com>
Cc:     Cong Wang <xiyou.wangcong@...il.com>,
        Network Development <netdev@...r.kernel.org>
Subject: Re: [Patch net] gre: refetch erspan header from skb->data after pskb_may_pull()

On Fri, Dec 6, 2019 at 3:50 AM Lorenzo Bianconi
<lorenzo.bianconi@...hat.com> wrote:
>
> >
> > After pskb_may_pull() we should always refetch the header
> > pointers from the skb->data in case it got reallocated.
> >
> > In gre_parse_header(), the erspan header is still fetched
> > from the 'options' pointer which is fetched before
> > pskb_may_pull().
> >
> > Found this during code review of a KMSAN bug report.
> >
> > Fixes: cb73ee40b1b3 ("net: ip_gre: use erspan key field for tunnel lookup")
> > Cc: Lorenzo Bianconi <lorenzo.bianconi@...hat.com>
> > Signed-off-by: Cong Wang <xiyou.wangcong@...il.com>
>
> Acked-by: Lorenzo Bianconi <lorenzo.bianconi@...hat.com>
>

LGTM.
Acked-by: William Tu <u9012063@...il.com>

>From the  spec, ERSPAN has fixed size GRE header, so  I think
WCCPv2 should not exist in ERSPAN.