Bluetooth: guard against controllers sending zero'd events

[ Upstream commit 08bb4da90150e2a225f35e0f642cdc463958d696 ]

Some controllers have been observed to send zero'd events under some
conditions.  This change guards against this condition as well as adding
a trace to facilitate diagnosability of this condition.

Signed-off-by: Alain Michaud <alainm@chromium.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 70b8e2de40cf43ed2b027e04a26d5b9867aa89be..1d2f439043669acc14c615eb5fec28b80bed4eee 100644 (file)
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -5257,6 +5257,11 @@ void hci_event_packet(struct hci_dev *hdev, struct sk_buff *skb)
        u8 status = 0, event = hdr->evt, req_evt = 0;
        u16 opcode = HCI_OP_NOP;
 
+       if (!event) {
+               bt_dev_warn(hdev, "Received unexpected HCI Event 00000000");
+               goto done;
+       }
+
        if (hdev->sent_cmd && bt_cb(hdev->sent_cmd)->hci.req_event == event) {
                struct hci_command_hdr *cmd_hdr = (void *) hdev->sent_cmd->data;
                opcode = __le16_to_cpu(cmd_hdr->opcode);
@@ -5468,6 +5473,7 @@ void hci_event_packet(struct hci_dev *hdev, struct sk_buff *skb)
                req_complete_skb(hdev, status, opcode, orig_skb);
        }
 
+done:
        kfree_skb(orig_skb);
        kfree_skb(skb);
        hdev->stat.evt_rx++;