[PATCH v1] Bluetooth: hci_h4: Fix padding calculation error within h4_recv_buf()

[PATCH v1] Bluetooth: hci_h4: Fix padding calculation error within h4_recv_buf()

[Zijun Hu]

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 */
-- 
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Re: [PATCH v1] Bluetooth: hci_h4: Fix padding calculation error within h4_recv_buf()

[Zijun Hu]

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 */
>