linux-kernel - Re: [PATCH v2 0/3] xen: harden blkfront against malicious backends

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Date:   Thu, 8 Jul 2021 16:39:58 +0200
From:   Juergen Gross <jgross@...e.com>
To:     Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Cc:     xen-devel@...ts.xenproject.org, linux-block@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        Stefano Stabellini <sstabellini@...nel.org>,
        Roger Pau Monné <roger.pau@...rix.com>,
        Jens Axboe <axboe@...nel.dk>
Subject: Re: [PATCH v2 0/3] xen: harden blkfront against malicious backends

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.

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


Juergen

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