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Subject: Re: [PATCH v2 3/3] xen/blkfront: don't trust the backend response
 data blindly
From:   Juergen Gross <jgross@suse.com>
To:     xen-devel@lists.xenproject.org, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org
Cc:     Boris Ostrovsky <boris.ostrovsky@oracle.com>,
        Stefano Stabellini <sstabellini@kernel.org>,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
        =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= <roger.pau@citrix.com>,
        Jens Axboe <axboe@kernel.dk>
References: <20210708124345.10173-1-jgross@suse.com>
 <20210708124345.10173-4-jgross@suse.com>
 <9ef58781-bd7d-48bc-2b59-bb71d2ba83b8@suse.com>
Message-ID: <68a2de1d-e377-61b0-6c69-5391ef95dbcd@suse.com>
Date:   Fri, 30 Jul 2021 12:31:07 +0200
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From: Juergen Gross <jgross@suse.com>
To: xen-devel@lists.xenproject.org, linux-block@vger.kernel.org,
 linux-kernel@vger.kernel.org
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>,
 Stefano Stabellini <sstabellini@kernel.org>,
 Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
 =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= <roger.pau@citrix.com>,
 Jens Axboe <axboe@kernel.dk>
Message-ID: <68a2de1d-e377-61b0-6c69-5391ef95dbcd@suse.com>
Subject: Re: [PATCH v2 3/3] xen/blkfront: don't trust the backend response
 data blindly
References: <20210708124345.10173-1-jgross@suse.com>
 <20210708124345.10173-4-jgross@suse.com>
 <9ef58781-bd7d-48bc-2b59-bb71d2ba83b8@suse.com>
In-Reply-To: <9ef58781-bd7d-48bc-2b59-bb71d2ba83b8@suse.com>

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On 30.07.21 12:08, Juergen Gross wrote:
> On 08.07.21 14:43, Juergen Gross wrote:
>> Today blkfront will trust the backend to send only sane response data.=

>> In order to avoid privilege escalations or crashes in case of maliciou=
s
>> backends verify the data to be within expected limits. Especially make=

>> sure that the response always references an outstanding request.
>>
>> Introduce a new state of the ring BLKIF_STATE_ERROR which will be
>> switched to in case an inconsistency is being detected. Recovering fro=
m
>> this state is possible only via removing and adding the virtual device=

>> again (e.g. via a suspend/resume cycle).
>>
>> Signed-off-by: Juergen Gross <jgross@suse.com>
>=20
> Any comments for this patch?

Please ignore this request for comments, I already got some.


Juergen

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