Re: [PATCH] usb: musb: Fix musb_gadget.c rxstate may cause request->buf overflow problems

[gregkh@xxxxxxxxxxxxxxxxxxx]

On Tue, Jul 26, 2022 at 01:59:48AM +0000, Andy Guo (郭卫斌) wrote:
> when the rxstate function executes the 'goto buffer_aint_mapped' code
> branch, it will always copy the fifocnt bytes data to request->buf,
> which may cause request->buf out of bounds. for Ethernet-over-USB will
> cause skb_over_panic when a packet larger than mtu is recived.
> 
> Fix it by add the length check :
> fifocnt = min_t(unsigned, request->length - request->actual, fifocnt);
> 
> Signed-off-by: guoweibin < <mailto:guoweibin@xxxxxxxxxx>
> guoweibin@xxxxxxxxxx>
> ---
>  drivers/usb/musb/musb_gadget.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c
> index 51274b87f46c..4ad5a1f31d7e 100644
> --- a/drivers/usb/musb/musb_gadget.c
> +++ b/drivers/usb/musb/musb_gadget.c
> @@ -760,6 +760,7 @@ static void rxstate(struct musb *musb, struct
> musb_request *req)
>   musb_writew(epio, MUSB_RXCSR, csr);
>  
>  buffer_aint_mapped:
> + fifo_count = min_t(unsigned, request->length - request->actual,
> fifo_count);
>   musb_read_fifo(musb_ep->hw_ep, fifo_count, (u8 *)
>   (request->buf + request->actual));
>   request->actual += fifo_count;
> 


Hi,

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