Date:   Tue, 2 Apr 2019 09:33:14 +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
Message-ID: <20190402063313.GA32613@kadam>
References: <20190330072511.GA5502@kadam>
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 <CAM_iQpVNqyoBirtKg-rbOHsOZCZ0Oz5PTE2sFQnHQnv6s7g2gg@mail.gmail.com>
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On Mon, Apr 01, 2019 at 11:03:53AM -0700, Cong Wang wrote:
> Hi,
> 
> On Sat, Mar 30, 2019 at 2:23 AM Tomas Bortoli <tomasbortoli@gmail.com> wrote:
> >
> > Hi Dan,
> >
> > On 3/30/19 8:25 AM, Dan Carpenter wrote:
> > > There is a potential out of bounds if "ev->length" is too high or if the
> > > number of reports are too many.
> > >
> > > Fixes: c215e9397b00 ("Bluetooth: Process extended ADV report event")
> > > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> > Reviewed-By: Tomas Bortoli <tomasbortoli@gmail.com>
> 
> I sent a patchset to fix all of this kind of OOB:
> https://marc.info/?l=linux-netdev&m=155314874622831&w=2
> 
> Unfortunately I get no response...
> 
> Does any of you mind to look at them?
> 

I don't know the rules...  When is it ok say:

	if (skb->len < sizeof(*ev))
		return;

and when must we say:

	if (!pskb_may_pull(skb, sizeof(*ev)))
		return;

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:

	struct hci_ev_pin_code_req *ev = (void *)skb->data;
	struct hci_conn *conn;

	if (!pskb_may_pull(skb, sizeof(*ev)))
		return;

regards,
dan carpenter