Re: [RFC] Restrict the untrusted devices, to bind to only a set of "whitelisted" drivers

From: Pavel Machek <pavel@denx.de>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Pavel Machek <pavel@denx.de>, Jesse Barnes <jsbarnes@google.com>,
	Rajat Jain <rajatja@google.com>,
	Rajat Jain <rajatxjain@gmail.com>,
	Bjorn Helgaas <helgaas@kernel.org>,
	"Raj, Ashok" <ashok.raj@intel.com>,
	"Krishnakumar,
	Lalithambika" <lalithambika.krishnakumar@intel.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	linux-pci <linux-pci@vger.kernel.org>,
	Mika Westerberg <mika.westerberg@linux.intel.com>,
	Jean-Philippe Brucker <jean-philippe@linaro.org>,
	Prashant Malani <pmalani@google.com>,
	Benson Leung <bleung@google.com>, Todd Broch <tbroch@google.com>,
	Alex Levin <levinale@google.com>,
	Mattias Nissler <mnissler@google.com>,
	Zubin Mithra <zsm@google.com>,
	Bernie Keany <bernie.keany@intel.com>,
	Aaron Durbin <adurbin@google.com>,
	Diego Rivas <diegorivas@google.com>,
	Duncan Laurie <dlaurie@google.com>,
	Furquan Shaikh <furquan@google.com>,
	Christian Kellner <christian@kellner.me>,
	Alex Williamson <alex.williamson@redhat.com>,
	Joerg Roedel <joro@8bytes.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [RFC] Restrict the untrusted devices, to bind to only a set of "whitelisted" drivers
Date: Wed, 1 Jul 2020 13:08:13 +0200	[thread overview]
Message-ID: <20200701110813.GA11023@amd> (raw)
In-Reply-To: <20200701105714.GA2098169@kroah.com>

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Hi!

> > > Yes, it originally was designed that way, but again, the world has
> > > changed so we have to change with it.  That is why USB has for a long
> > > time now, allowed you to not bind drivers to devices that you do not
> > > "trust", and that trust can be determined by userspace.  That all came
> > > about thanks to the work done by the wireless USB spec people and kernel
> > > authors, which showed that maybe you just don't want to trust any device
> > > that comes within range of your system :)
> > 
> > Again, not disagreeing; but note the scale here.
> > 
> > It is mandatory to defend against malicious wireless USB devices.
> 
> Turns out there are no more wireless USB devices in the world, and the
> code for that is gone from Linux :)
> 
> > We probably should work on robustness against malicious USB devices.
> 
> We are, and do have, that support today.
> 
> > Malicious PCI-express devices are lot less of concern.
> 
> Not really, they are a lot of concern to some people.  Valid attacks are
> out there today, see the thunderbolt attacks that numerous people have
> done and published recently and for many years.

In this case PCI-express meant internal cards in PCs. Yes, thunderbolt
would be higher concern than internal card.

> > Defending against malicious CPU/RAM does not make much sense.
> 
> That's what the spectre and rowhammer fixes have been for :)

Yeah, and that's why we have whitelist of working CPUs and only work
on those, riiight? :-). [There's difference between "malicious" and
"buggy".]

								Pavel
-- 
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany

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