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

From: Greg Kroah-Hartman
Date: Tue Nov 26 2019 - 03:13:05 EST


On Tue, Nov 26, 2019 at 07:18:46AM +0100, Marcel Holtmann wrote:
> Hi Alexander,
>
> >>> 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.
>
> I do not have a reproducer for it, but if you do, feel free to propose it for -stable inclusion.

Now queued up, thanks.

greg k-h