linux-kernel - Re: [PATCH 1/1] usb: musb: gadget: misplaced out of bounds check

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:   Mon, 19 Mar 2018 11:26:49 -0500
From:   Bin Liu <b-liu@...com>
To:     Heinrich Schuchardt <xypron.glpk@....de>
CC:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        <linux-usb@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/1] usb: musb: gadget: misplaced out of bounds check

Hi,

On Mon, Mar 19, 2018 at 08:12:28AM +0100, Heinrich Schuchardt wrote:
> musb->endpoints[] has array size MUSB_C_NUM_EPS.
> We must check array bounds before accessing the array and not afterwards.
> 
> Signed-off-by: Heinrich Schuchardt <xypron.glpk@....de>
> ---
>  drivers/usb/musb/musb_gadget_ep0.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/musb/musb_gadget_ep0.c b/drivers/usb/musb/musb_gadget_ep0.c
> index 18da4873e52e..482e7c2f8dc7 100644
> --- a/drivers/usb/musb/musb_gadget_ep0.c
> +++ b/drivers/usb/musb/musb_gadget_ep0.c
> @@ -88,6 +88,11 @@ static int service_tx_status_request(
>  			break;
>  		}
>  
> +		if (epnum >= MUSB_C_NUM_EPS) {

only the LSB 4 bits are the EP number, bit7 is the direction flag. So
you can only compare the LSB 4 bits here.

Regards,
-Bin.