[PATCH AUTOSEL 5.4 031/108] Bluetooth: guard against controllers sending zero'd events

Sasha Levin
2020-04-11T23:31:23Z

From: Alain Michaud <alainm@chromium.org>

[ 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>
---
net/bluetooth/hci_event.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index c1d3a303d97fb..34d312ae3c61d 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -5833,6 +5833,11 @@ 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);
@@ -6044,6 +6049,7 @@ 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++;
--
2.20.1