Date: Thu, 24 Nov 2016 21:19:39 +0100
From: Dominik Brodowski <linux@dominikbrodowski.net>
To: David Howells <dhowells@redhat.com>
Cc: keyrings@vger.kernel.org, matthew.garrett@nebula.com,
        linux-security-module@vger.kernel.org, linux-efi@vger.kernel.org,
        linux-kernel@vger.kernel.org, gnomes@lxorguk.ukuu.org.uk
Subject: Re: [PATCH] Lock down drivers that can have io ports, io mem, irqs
 and dma changed
Message-ID: <20161124201939.GA3782@isilmar-4.linta.de>
References: <20161123192143.GA482@light.dominikbrodowski.net>
 <20161122061233.GA4762@light.dominikbrodowski.net>
 <20161116222731.563fb85e@lxorguk.ukuu.org.uk>
 <147933283664.19316.12454053022687659937.stgit@warthog.procyon.org.uk>
 <26173.1479769852@warthog.procyon.org.uk>
 <8342.1479905906@warthog.procyon.org.uk>
 <30473.1480008885@warthog.procyon.org.uk>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <30473.1480008885@warthog.procyon.org.uk>
User-Agent: Mutt/1.5.23 (2014-03-12)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 902
Lines: 22

On Thu, Nov 24, 2016 at 05:34:45PM +0000, David Howells wrote:
> Dominik Brodowski <linux@dominikbrodowski.net> wrote:
> 
> > > > 	- Abort in drivers/pcmcia/cistpl.c::pccard_store_cis() or remove
> > > > 	  write access to the "cis" file in
> > > > 	  drivers/pcmcia/cistpl.c::pccard_cis_attr
> > > 
> > > What is that doing?  Allowing the device to be reconfigured?
> > 
> > Exactly. It is a different interface for updating the firmware -- which
> > includes ioports etc. In theory, any access should be limited to areas which
> > are registered to the bridge devices. But you never know...
> 
> Ah, I see.  Should this be using request_firmware()?

For most cases, request_firmware() is being used -- for some rare cases,
however, this alternative interface is provided for. It should be pretty
safe nowadays to make pccard_cis_attr read-only (and who uses PCMCIA
nowadays anyway?).

Best,
	Dominik