Date:   Thu, 4 Apr 2019 09:35:21 +0300
From:   Dan Carpenter <dan.carpenter@oracle.com>
To:     Cong Wang <xiyou.wangcong@gmail.com>
Cc:     Tomas Bortoli <tomasbortoli@gmail.com>,
        Marcel Holtmann <marcel@holtmann.org>,
        Jaganath Kanakkassery <jaganath.k.os@gmail.com>,
        Johan Hedberg <johan.hedberg@gmail.com>,
        linux-bluetooth <linux-bluetooth@vger.kernel.org>,
        kernel-janitors@vger.kernel.org
Subject: Re: [PATCH] Bluetooth: hci_event: potential out of bounds parsing
 ADV events
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On Wed, Apr 03, 2019 at 03:51:18PM -0700, Cong Wang wrote:
> On Tue, Apr 2, 2019 at 1:15 PM Dan Carpenter <dan.carpenter@oracle.com> wrote:
> >
> > On Tue, Apr 02, 2019 at 10:42:38AM -0700, Cong Wang wrote:
> > > > Btw, get rid of all the likely/unlikely() macros.  Then the other style
> > > > comment would be don't move the "ev = (void *)skb->data;" assignments
> > > > around.  It's ok to say:
> > >
> > >
> > > Similarly, pskb_may_pull() may reallocate skb's, although very unlikely
> > > for bluetooth case (skb's are linear). At least it doesn't harm anything
> > > we move the skb->data dereference after pskb_may_pull().
> > >
> >
> > It harms readability.
> 
> Why? I can't see how it harms readability if you have pskb_may_pull()
> in mind that it potentially reallocates skb->data.

You're making the code more complicated because you're pretending that
we didn't linearize the skb data already...  :/

regards,
dan carpenter