Re: [PATCH] Bluetooth: hci_core: remove acl hdr handle error message

[Luiz Augusto von Dentz]

Hi Edward,

On Tue, Oct 8, 2024 at 6:47 AM Edward Adam Davis <eadavis@xxxxxx> wrote:
>
> Syzbot reported a uninit-value in hci_rx_work.This is because l2cap didn't
> execute the corresponding connection request to call l2cap_send_cmd() or
> l2cap_do_send(), and ultimately called hci_add_acl_hdr() to set hdr->handle.

What are you talking about here, what these functions have to do with
a local handle variable?

> Therefore, when calling the thread callback function hci_rx_work() to call
> hci_acldata_packet, hdr->handle should not be used directly.

It is not being used directly, the handle is a local variable which
get assigned:

    handle = __le16_to_cpu(hdr->handle);

If what you are saying is that there is no guarantee that skb->len >=
HCI_ACL_HDR_SIZE then we probably want to replace skb_pull with
skb_pull_data.

> Reported-and-tested-by: syzbot+6ea290ba76d8c1eb1ac2@xxxxxxxxxxxxxxxxxxxxxxxxx
> Closes: https://syzkaller.appspot.com/bug?extid=6ea290ba76d8c1eb1ac2
> Signed-off-by: Edward Adam Davis <eadavis@xxxxxx>
> ---
>  net/bluetooth/hci_core.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
> index d6976db02c06..20605a7f3f4e 100644
> --- a/net/bluetooth/hci_core.c
> +++ b/net/bluetooth/hci_core.c
> @@ -3791,8 +3791,7 @@ static void hci_acldata_packet(struct hci_dev *hdev, struct sk_buff *skb)
>                 l2cap_recv_acldata(conn, skb, flags);
>                 return;
>         } else {
> -               bt_dev_err(hdev, "ACL packet for unknown connection handle %d",
> -                          handle);
> +               bt_dev_err(hdev, "ACL packet for unknown connection handle");
>         }
>
>         kfree_skb(skb);
> --
> 2.43.0
>


-- 
Luiz Augusto von Dentz