commit f7e0e8b2f1b0a09b527885babda3e912ba820798 upstream.

`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.

Backporting notes: - Rebased on linux-4.14.y, commit 3f2ecb86cb90 ("Linux 4.14.212") - Retested by syzbot

Cc: stable@vger.kernel.org Fixes: 2f010b55884e ("Bluetooth: Add support for handling LE Direct Advertising Report events") Reported-and-tested-by: syzbot+24ebd650e20bd263ca01@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?extid=24ebd650e20bd263ca01 Signed-off-by: Peilin Ye yepeilin.cs@gmail.com Signed-off-by: Marcel Holtmann marcel@holtmann.org --- 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 ba12bf8de826..0db218b14bf3 100644 --- a/net/bluetooth/hci_event.c +++ b/net/bluetooth/hci_event.c @@ -5141,20 +5141,18 @@ 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);

- ptr += sizeof(*ev); - } - hci_dev_unlock(hdev); }