Re: [PATCH] Fix invalid-free in bcsp_close()

[Alexander Potapenko]

Hi Tomas, Marcel, Greg,

On Mon, Nov 4, 2019 at 3:20 PM Marcel Holtmann <marcel@xxxxxxxxxxxx> wrote:
>
> Hi Tomas,
>
> > Syzbot reported an invalid-free that I introduced fixing a memleak.
> >
> > bcsp_recv() also frees bcsp->rx_skb but never nullifies its value.
> > Nullify bcsp->rx_skb every time it is freed.
> >
> > Signed-off-by: Tomas Bortoli <tomasbortoli@xxxxxxxxx>
> > Reported-by: syzbot+a0d209a4676664613e76@xxxxxxxxxxxxxxxxxxxxxxxxx
> > ---
> > drivers/bluetooth/hci_bcsp.c | 3 +++
> > 1 file changed, 3 insertions(+)
>
> patch has been applied to bluetooth-next tree.
I believe this bug requires stable tags, as it can potentially provide
an arbitrary write (via __skb_unlink) and is triggerable locally with
user privileges.
> Regards
>
> Marcel
>
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Alexander Potapenko
Software Engineer

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