Re: [PATCH] usb: typec: anx7411: Fix possible buffer overflow in anx7411_send_msg()

[Heikki Krogerus <heikki.krogerus@linux.intel.com>]

On Sat, Mar 16, 2024 at 11:33:53PM +0300, Grigory Bazilevich wrote:
> Passing a size argument greater than or equal to MAX_BUF_LEN causes
> a buffer overflow when the checksum is written.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> Fixes: fe6d8a9c8e64 ("usb: typec: anx7411: Add Analogix PD ANX7411 support")
> Signed-off-by: Grigory Bazilevich <bazilevich@sicamp.ru>

Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>

> ---
>  drivers/usb/typec/anx7411.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/typec/anx7411.c b/drivers/usb/typec/anx7411.c
> index b12a07edc71b..70ba56dfb22b 100644
> --- a/drivers/usb/typec/anx7411.c
> +++ b/drivers/usb/typec/anx7411.c
> @@ -733,7 +733,7 @@ static int anx7411_send_msg(struct anx7411_data *ctx, u8 type, u8 *buf, u8 size)
>  	u8 crc;
>  	int ret;
>  
> -	size = min_t(u8, size, (u8)MAX_BUF_LEN);
> +	size = min_t(u8, size, (u8)(MAX_BUF_LEN - 1));
>  	memcpy(msg->buf, buf, size);
>  	msg->msg_type = type;
>  	/* msg len equals buffer length + msg_type */
> -- 
> 2.39.2

-- 
heikki