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Subject: Re: [PATCH v2 04/10] Bluetooth: HCI: Use skb_pull to parse Inquiry
 Result event
From:   Marcel Holtmann <marcel@holtmann.org>
In-Reply-To: <20210419171257.3865181-5-luiz.dentz@gmail.com>
Date:   Fri, 23 Apr 2021 14:28:27 +0200
Cc:     linux-bluetooth@vger.kernel.org
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Message-Id: <BB6AA021-E6B3-46BA-B394-1C1DCE53B123@holtmann.org>
References: <20210419171257.3865181-1-luiz.dentz@gmail.com>
 <20210419171257.3865181-5-luiz.dentz@gmail.com>
To:     Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Precedence: bulk

Hi Luiz,

> This uses skb_pull to check the Inquiry Result events received have
> the minimum required length.
> 
> Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
> ---
> include/net/bluetooth/hci.h |  5 +++++
> net/bluetooth/hci_event.c   | 19 ++++++++++++++-----
> 2 files changed, 19 insertions(+), 5 deletions(-)
> 
> diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
> index 9251ae3a2ce0..b65205b4d830 100644
> --- a/include/net/bluetooth/hci.h
> +++ b/include/net/bluetooth/hci.h
> @@ -1910,6 +1910,11 @@ struct inquiry_info {
> 	__le16   clock_offset;
> } __packed;
> 
> +struct hci_ev_inquiry_result {
> +	__u8    num;
> +	struct inquiry_info info[];
> +};
> +
> #define HCI_EV_CONN_COMPLETE		0x03
> struct hci_ev_conn_complete {
> 	__u8     status;
> diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
> index c353dfafb04c..6516538fe238 100644
> --- a/net/bluetooth/hci_event.c
> +++ b/net/bluetooth/hci_event.c
> @@ -2990,13 +2990,21 @@ static void hci_inquiry_complete_evt(struct hci_dev *hdev, struct sk_buff *skb)
> 
> static void hci_inquiry_result_evt(struct hci_dev *hdev, struct sk_buff *skb)
> {
> +	struct hci_ev_inquiry_result *ev;
> 	struct inquiry_data data;
> -	struct inquiry_info *info = (void *) (skb->data + 1);
> -	int num_rsp = *((__u8 *) skb->data);
> +	int i;
> 
> -	BT_DBG("%s num_rsp %d", hdev->name, num_rsp);
> +	ev = hci_ev_skb_pull(hdev, skb, HCI_EV_INQUIRY_RESULT, sizeof(*ev));
> +	if (!ev)
> +		return;
> 
> -	if (!num_rsp || skb->len < num_rsp * sizeof(*info) + 1)
> +	if (!hci_ev_skb_pull(hdev, skb, HCI_EV_INQUIRY_RESULT,
> +			     flex_array_size(ev, info, ev->num)))
> +		return;
> +
> +	BT_DBG("%s num %d", hdev->name, ev->num);

please switch to bt_dev_dbg() here.

Regards

Marcel