Re: [PATCH v2 0/3] xen: harden blkfront against malicious backends - Marek Marczykowski-Górecki

From: "Marek Marczykowski-Górecki" <marmarek@invisiblethingslab.com>
To: Juergen Gross <jgross@suse.com>
Cc: "Konrad Rzeszutek Wilk" <konrad.wilk@oracle.com>,
	xen-devel@lists.xenproject.org, linux-block@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	"Boris Ostrovsky" <boris.ostrovsky@oracle.com>,
	"Stefano Stabellini" <sstabellini@kernel.org>,
	"Roger Pau Monné" <roger.pau@citrix.com>,
	"Jens Axboe" <axboe@kernel.dk>
Subject: Re: [PATCH v2 0/3] xen: harden blkfront against malicious backends
Date: Sat, 10 Jul 2021 03:18:02 +0200	[thread overview]
Message-ID: <YOj1Spa1hitL61j/@mail-itl> (raw)
In-Reply-To: <0baeba93-39eb-2bae-1abd-d4e17e6e025e@suse.com>

[-- Attachment #1: Type: text/plain, Size: 1860 bytes --]

On Thu, Jul 08, 2021 at 04:39:58PM +0200, Juergen Gross wrote:
> On 08.07.21 16:22, Konrad Rzeszutek Wilk wrote:
> > On Thu, Jul 08, 2021 at 02:43:42PM +0200, Juergen Gross wrote:
> > > Xen backends of para-virtualized devices can live in dom0 kernel, dom0
> > > user land, or in a driver domain. This means that a backend might
> > > reside in a less trusted environment than the Xen core components, so
> > > a backend should not be able to do harm to a Xen guest (it can still
> > > mess up I/O data, but it shouldn't be able to e.g. crash a guest by
> > > other means or cause a privilege escalation in the guest).
> > > 
> > > Unfortunately blkfront in the Linux kernel is fully trusting its
> > > backend. This series is fixing blkfront in this regard.
> > > 
> > > It was discussed to handle this as a security problem, but the topic
> > > was discussed in public before, so it isn't a real secret.
> > 
> > Wow. This looks like what Marek did .. in 2018!
> > 
> > https://lists.xenproject.org/archives/html/xen-devel/2018-04/msg02336.html
> 
> Yes, seems to have been a similar goal.
> 
> > Would it be worth crediting Marek?
> 
> I'm fine mentioning his patches, but I didn't know of his patches until
> having sent out V1 of my series.

Some email issue likely? You were on explicit CC in that series.

> I'd be interested in learning why his patches haven't been taken back
> then.

Mostly it was waiting in limbo on "public: add RING_COPY_RESPONSE()"[1] patch
to the Xen tree, to be then synchronized back to Linux headers. That patch
was finally committed in March this year. I should've followed up on it,
earlier than 3 years later...

[1] https://lore.kernel.org/xen-devel/20180430215436.21062-1-marmarek@invisiblethingslab.com/T/#u

-- 
Best Regards,
Marek Marczykowski-Górecki
Invisible Things Lab

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 488 bytes --]