On Mon, Nov 09, 2020 at 01:16:53PM +0100, Marcel Holtmann wrote:
> Hi Peilin,
>
> > `num_reports` is not being properly checked. A malformed event packet with
> > a large `num_reports` number makes hci_le_direct_adv_report_evt() read out
> > of bounds. Fix it.
> >
> > Cc: stable@xxxxxxxxxxxxxxx
> > Fixes: 2f010b55884e ("Bluetooth: Add support for handling LE Direct Advertising Report events")
> > Reported-and-tested-by: syzbot+24ebd650e20bd263ca01@xxxxxxxxxxxxxxxxxxxxxxxxx
> > Link: https://syzkaller.appspot.com/bug?extid=24ebd650e20bd263ca01
> > Signed-off-by: Peilin Ye <yepeilin.cs@xxxxxxxxx>
> > ---
> > Change in v2:
> > - add "Cc: stable@" tag.
> >
> > net/bluetooth/hci_event.c | 12 +++++-------
> > 1 file changed, 5 insertions(+), 7 deletions(-)
> >
> > diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
> > index 4b7fc430793c..aec43ae488d1 100644
> > --- a/net/bluetooth/hci_event.c
> > +++ b/net/bluetooth/hci_event.c
> > @@ -5863,21 +5863,19 @@ static void hci_le_direct_adv_report_evt(struct hci_dev *hdev,
> > struct sk_buff *skb)
> > {
> > u8 num_reports = skb->data[0];
> > - void *ptr = &skb->data[1];
> > + struct hci_ev_le_direct_adv_info *ev = (void *)&skb->data[1];
> >
> > - hci_dev_lock(hdev);
> > + if (!num_reports || skb->len < num_reports * sizeof(*ev) + 1)
> > + return;
> >
> > - while (num_reports--) {
> > - struct hci_ev_le_direct_adv_info *ev = ptr;
> > + hci_dev_lock(hdev);
> >
> > + for (; num_reports; num_reports--, ev++)
> > process_adv_report(hdev, ev->evt_type, &ev->bdaddr,
> > ev->bdaddr_type, &ev->direct_addr,
> > ev->direct_addr_type, ev->rssi, NULL, 0,
> > false);
> >
> > - ptr += sizeof(*ev);
> > - }
> > -
> > hci_dev_unlock(hdev);
> > }
>
> patch has been applied to bluetooth-next tree.
Thank you for reviewing it,
Peilin Ye
