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

[gregkh@xxxxxxxxxxxxxxxxxxx]

On Wed, Jul 27, 2022 at 07:21:39AM +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 <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,

This is the friendly patch-bot of Greg Kroah-Hartman.  You have sent him
a patch that has triggered this response.  He used to manually respond
to these common problems, but in order to save his sanity (he kept
writing the same thing over and over, yet to different people), I was
created.  Hopefully you will not take offence and will fix the problem
in your patch and resubmit it so that it can be accepted into the Linux
kernel tree.

You are receiving this message because of the following common error(s)
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  Please read the section entitled "The canonical patch format" in the
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thanks,

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