Re: [PATCH 2/5] Bluetooth: btmrvl: validate event packet lengths

[Marek Szyprowski <m.szyprowski@samsung.com>]

On 16.07.2026 10:47, Li Qiang wrote:
> The Marvell event handlers access the HCI event header, command
> complete payload, and driver-specific event header before validating
> that the received skb contains them. A truncated event can consequently
> cause an out-of-bounds read.
>
> Validate each header and the command-complete payload length before
> dereferencing the corresponding fields.
>
> Signed-off-by: Li Qiang <liqiang01@kylinos.cn>

This patch landed in linux-next as commit 75e574f6a212 ("Bluetooth: btmrvl:

validate event packet lengths"). In my tests I found that it breaks bluetooth

driver operation on old Samsung Exynos SoC based Peach Pit/Pi Chromebooks.


I've sent a fix for this issue here:

https://lore.kernel.org/all/20260804094632.87581-1-m.szyprowski@samsung.com/


> ---
>  drivers/bluetooth/btmrvl_main.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
>
> diff --git a/drivers/bluetooth/btmrvl_main.c b/drivers/bluetooth/btmrvl_main.c
> index d6f0ad0b4b6e..aaf1614ccfd7 100644
> --- a/drivers/bluetooth/btmrvl_main.c
> +++ b/drivers/bluetooth/btmrvl_main.c
> @@ -43,10 +43,17 @@ bool btmrvl_check_evtpkt(struct btmrvl_private *priv, struct sk_buff *skb)
>  {
>  	struct hci_event_hdr *hdr = (void *) skb->data;
>  
> +	if (skb->len < sizeof(*hdr))
> +		return true;
> +
>  	if (hdr->evt == HCI_EV_CMD_COMPLETE) {
>  		struct hci_ev_cmd_complete *ec;
>  		u16 opcode;
>  
> +		if (hdr->plen < sizeof(*ec) ||
> +		    skb->len < HCI_EVENT_HDR_SIZE + sizeof(*ec))
> +			return true;
> +
>  		ec = (void *) (skb->data + HCI_EVENT_HDR_SIZE);
>  		opcode = __le16_to_cpu(ec->opcode);
>  
> @@ -74,6 +81,9 @@ int btmrvl_process_event(struct btmrvl_private *priv, struct sk_buff *skb)
>  	struct btmrvl_event *event;
>  	int ret = 0;
>  
> +	if (skb->len < sizeof(*event))
> +		return -EINVAL;
> +
>  	event = (struct btmrvl_event *) skb->data;
>  	if (event->ec != 0xff) {
>  		BT_DBG("Not Marvell Event=%x", event->ec);

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland