From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
dgdegra@tycho.nsa.gov, xen-devel@lists.xenproject.org
Subject: Re: XSM permissive by default.
Date: Wed, 9 Mar 2016 13:24:15 +0000 [thread overview]
Message-ID: <56E023FF.1020706@citrix.com> (raw)
In-Reply-To: <20160309015100.GA5420@localhost.localdomain>
On 09/03/16 01:51, Konrad Rzeszutek Wilk wrote:
> Hey,
>
> I was wondering if it we should change the default flask_bootparam
> option from permissive to disabled?
>
> The reason being is that I was startled to see that my xSplice
> code was able to patch the hypervisor from within an PV guest!
>
> Further testing showed that I could do 'xl debug-keys R' from
> within the guests. This being possible with released 4.6 if I have
> XSM enabled.
>
> All of this is due to the fact that I had forgotten to load the policy,
> but Xen just told me:
>
> Flask: Access controls disabled until policy is loaded.
>
> which is an understatement. I somehow had expected that if no
> policy was loaded it would revert to the dummy one which has the
> same permission as the non-XSM build. Ha! What a surprise..
>
> Now that the XSM is enabled via config it becomes much more
> easy to enable it..
>
> Or perhaps change the code to flask so that if there are any
> errors loading the policy it uses the dummy one?
By the looks of it, "permissive" shouldn't be an available option at all.
If a misconfiguration occurs, the behaviour should revert back to the
current "dom0 all powerful, everything else unprivileged" state which
currently exists without XSM.
~Andrew
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next prev parent reply other threads:[~2016-03-09 13:24 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-09 1:51 XSM permissive by default Konrad Rzeszutek Wilk
2016-03-09 2:11 ` Doug Goldstein
2016-03-09 13:24 ` Andrew Cooper [this message]
2016-03-09 21:17 ` Konrad Rzeszutek Wilk
2016-03-09 22:09 ` Daniel De Graaf
2016-03-10 2:40 ` Doug Goldstein
2016-03-10 17:10 ` Konrad Rzeszutek Wilk
2016-03-10 17:34 ` Doug Goldstein
2016-03-10 17:44 ` Andrew Cooper
2016-03-10 18:30 ` [PATCH] flask: change default state to enforcing Daniel De Graaf
2016-03-10 19:12 ` Konrad Rzeszutek Wilk
2016-03-10 19:37 ` Daniel De Graaf
2016-03-15 14:48 ` Anshul Makkar
2016-03-11 9:07 ` Jan Beulich
2016-03-11 14:58 ` Konrad Rzeszutek Wilk
2016-03-11 15:39 ` Daniel De Graaf
2016-03-11 15:43 ` Jan Beulich
2016-03-11 15:51 ` Daniel De Graaf
2016-04-04 17:12 ` XSM permissive by default Ian Jackson
2016-04-05 8:03 ` Jan Beulich
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