From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dario Faggioli Subject: Re: [PATCH v2] features: declare the Credit2 scheduler as Supported. Date: Wed, 2 Nov 2016 12:22:40 +0100 Message-ID: <1478085760.24942.32.camel@citrix.com> References: <147808213853.22655.18440819543503331735.stgit@Solace.fritz.box> <5819D525020000780011B8EA@prv-mh.provo.novell.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============0130944025536600859==" Return-path: Received: from mail6.bemta3.messagelabs.com ([195.245.230.39]) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1c1td4-0005uU-W7 for xen-devel@lists.xenproject.org; Wed, 02 Nov 2016 11:22:51 +0000 In-Reply-To: <5819D525020000780011B8EA@prv-mh.provo.novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xen.org Sender: "Xen-devel" To: Jan Beulich Cc: Lars Kurth , Stefano Stabellini , Wei Liu , George Dunlap , Andrew Cooper , Anshul Makkar , Ian Jackson , Tim Deegan , security@xenproject.org, xen-devel@lists.xenproject.org List-Id: xen-devel@lists.xenproject.org --===============0130944025536600859== Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="=-fbcv0pZrzhXzEEgROq3x" --=-fbcv0pZrzhXzEEgROq3x Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Wed, 2016-11-02 at 04:59 -0600, Jan Beulich wrote: > > > > On 02.11.16 at 11:22, wrote: > > The control domain can issue DOMCTL_SCHEDOP and SYSCTL_SCHEDOP > > hypercalls. Auditing such code, nothing that looks like a security > > risk has been found (E.g., there's no risk of leaking content of > > the hypervisor stack, as no buffer/local variables is returned). >=20 > There certainly are buffers being returned here. Namely in the > credit2 case there's also a 32-bit padding field in the domctl > interface structure (and uniformly for all schedulers there's one > in the sysctl structure), which provides the fundamental means > to leak stack data. However, none of this is a problem, both > because iirc leaking stack data to Dom0 is not really considered > a security issue, and because of the way the structures get > dealt with.=20 > Right, what I meant is really "none of this is a problem [...] because of the way the structures get dealt with". I.e., there is nothing like what made=C2=A0e0e3b8f64730f3ee necessary. > Nevertheless I think the above paragraph should be > re-worded. >=20 Yep, I certainly could have said it better. But if leaking to Dom0 is not worth being considered, I guess I can just remove the paragraph entirely, can't I? Thanks and Regards, Dario --=20 <> (Raistlin Majere) ----------------------------------------------------------------- Dario Faggioli, Ph.D, http://about.me/dario.faggioli Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK) --=-fbcv0pZrzhXzEEgROq3x Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAABCAAGBQJYGcyBAAoJEBZCeImluHPulBIP/jSSft1DvJvqvsTUQCRmuE6r eyYSHbawu4Hfd6Ng2Rxxr6E1IBzZN0UZEFAVsFgmoymAgum+eGljb2CWfEtaMJET PiColDXQUpiMve+lJew9lS+foUfpzbRZvjC4wKzxYfXLs/hHFxSys1YHM2nGNvAk KNTTPp2WI9IcppfWHXkj02RECbuvcM1tRbQJ8cMM9jhthqbr3UuJmxckJVmhCF3c KofEUiZtQzju/3l5q22S4Q0xP4eubxRLp6gO2+xAd/NmQsD8LdlGgp+OPmu058xo iqrRjSARH2xZEHxXbsfwdtzQ8WfAEV2LgV2JQfMlukLuDpP2UY9mCZLmGXAUolFD IV3juvx+41UBPyj5JGbEnNmd5FC8eqp36VkX3QQimQVJq1lMjKSrzsQ8aYSlGfw0 oVLd4JR8j+ziTdE/ZhnfAnwRfBg5PtRkU2drj8Azaz8ND9mdn18OpIcFXXSK6fkP T4jDrVo7aiDg573w2yyZ7VMwRRZC8F+dB5Qr6Czv+nhoGjL333nlgD2JXwerE3Ik eebuaDu5Q5EK0aFi/MpfDO4d6AyDPMWceV/9VPn96sjlIoyiU83/IOSW/iHlX0aP z54Exj5LK78iKO5ifpmlSsfeZVgDZv6yKUzwYZvzvyG7/OVZP7rVOvd2ILmXBsYK yBuOuFxhv3oKCMHVBvr6 =yUPj -----END PGP SIGNATURE----- --=-fbcv0pZrzhXzEEgROq3x-- --===============0130944025536600859== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Content-Disposition: inline X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KWGVuLWRldmVs IG1haWxpbmcgbGlzdApYZW4tZGV2ZWxAbGlzdHMueGVuLm9yZwpodHRwczovL2xpc3RzLnhlbi5v cmcveGVuLWRldmVsCg== --===============0130944025536600859==--