linux-kernel - Re: [PATCH] xen: fix potential shift out-of-bounds in xenhcd_hub

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

Date:   Mon, 26 Jun 2023 07:52:02 +0200
From:   Greg KH <gregkh@...uxfoundation.org>
To:     Jan Beulich <jbeulich@...e.com>,
        Zhang Shurong <zhang_shurong@...mail.com>
Cc:     xen-devel@...ts.xenproject.org, linux-usb@...r.kernel.org,
        linux-kernel@...r.kernel.org, jgross@...e.com
Subject: Re: [PATCH] xen: fix potential shift out-of-bounds in
 xenhcd_hub_control()

On Mon, Jun 26, 2023 at 07:48:05AM +0200, Jan Beulich wrote:
> On 25.06.2023 18:42, Zhang Shurong wrote:
> > --- a/drivers/usb/host/xen-hcd.c
> > +++ b/drivers/usb/host/xen-hcd.c
> > @@ -456,6 +456,8 @@ static int xenhcd_hub_control(struct usb_hcd *hcd, __u16 typeReq, __u16 wValue,
> >  			info->ports[wIndex - 1].c_connection = false;
> >  			fallthrough;
> >  		default:
> > +			if (wValue >= 32)
> > +				goto error;
> >  			info->ports[wIndex - 1].status &= ~(1 << wValue);
> 
> Even 31 is out of bounds (as in: UB) as long as it's 1 here rather
> than 1u.

Why isn't the caller fixed so this type of value could never be passed
to the hub_control callback?

thanks,

greg k-h