Sender: zijuhu=codeaurora.org@mg.codeaurora.org
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Subject: Re: [PATCH v1] Bluetooth: hci_h4: Fix padding calculation error
 within h4_recv_buf()
To:     marcel@holtmann.org, johan.hedberg@gmail.com, luiz.dentz@gmail.com
Cc:     linux-kernel@vger.kernel.org, linux-bluetooth@vger.kernel.org,
        linux-arm-msm@vger.kernel.org, c-hbandi@codeaurora.org,
        hemantg@codeaurora.org, rjliao@codeaurora.org,
        Zijun Hu <quic_zijuhu@quicinc.com>
References: <1636546159-8339-1-git-send-email-zijuhu@codeaurora.org>
From:   Zijun Hu <zijuhu@codeaurora.org>
Message-ID: <97e8c186-3c4f-a3ff-8389-e15ea476280e@codeaurora.org>
Date:   Sun, 14 Nov 2021 20:46:25 +0800
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could you please code review for this patch?

On 11/10/2021 8:09 PM, Zijun Hu wrote:
> From: Zijun Hu <quic_zijuhu@quicinc.com>
> 
> it is erroneous to calculate padding by subtracting length of type
> indication from skb->len, it will cause data analysis error for
> alignment which is greater than 1, so fixed by adding length of type
> indication with skb->len.
> 
> Signed-off-by: Zijun Hu <quic_zijuhu@quicinc.com>
> ---
>  drivers/bluetooth/hci_h4.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/bluetooth/hci_h4.c b/drivers/bluetooth/hci_h4.c
> index 4b3b14a34794..1d0cdf023243 100644
> --- a/drivers/bluetooth/hci_h4.c
> +++ b/drivers/bluetooth/hci_h4.c
> @@ -252,7 +252,7 @@ struct sk_buff *h4_recv_buf(struct hci_dev *hdev, struct sk_buff *skb,
>  			}
>  
>  			if (!dlen) {
> -				hu->padding = (skb->len - 1) % alignment;
> +				hu->padding = (skb->len + 1) % alignment;
>  				hu->padding = (alignment - hu->padding) % alignment;
>  
>  				/* No more data, complete frame */
> @@ -260,7 +260,7 @@ struct sk_buff *h4_recv_buf(struct hci_dev *hdev, struct sk_buff *skb,
>  				skb = NULL;
>  			}
>  		} else {
> -			hu->padding = (skb->len - 1) % alignment;
> +			hu->padding = (skb->len + 1) % alignment;
>  			hu->padding = (alignment - hu->padding) % alignment;
>  
>  			/* Complete frame */
>