2021-11-10 12:11:59

by Zijun Hu

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

From: Zijun Hu <[email protected]>

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 <[email protected]>
---
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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2021-11-14 12:46:57

by Zijun Hu

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

could you please code review for this patch?

On 11/10/2021 8:09 PM, Zijun Hu wrote:
> From: Zijun Hu <[email protected]>
>
> 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 <[email protected]>
> ---
> 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 */
>