2020-03-02 15:44:02

by Alain Michaud

Subject: [PATCH v2] bluetooth: guard against controllers sending zero'd events

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 <[email protected]>
---

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 591e7477e925..56305b3a865e 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -5868,6 +5868,12 @@ 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");
+ kfree_skb(skb);
+ hdev->stat.evt_rx++;
+ }
+
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);
--
2.25.0.265.gbab2e86ba0-goog

2020-03-02 22:13:10

by Marcel Holtmann

Subject: Re: [PATCH v2] bluetooth: guard against controllers sending zero'd events

Hi Alain,

> 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 <[email protected]>
> ---
>
> 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 591e7477e925..56305b3a865e 100644
> --- a/net/bluetooth/hci_event.c
> +++ b/net/bluetooth/hci_event.c
> @@ -5868,6 +5868,12 @@ 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");
> + kfree_skb(skb);
> + hdev->stat.evt_rx++;
> + }
> +
> 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);

what about doing just this:

@@ -5868,6 +5868,11 @@ 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, ..);
+ 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);
@@ -6079,6 +6084,7 @@ 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++;

Regards

Marcel