From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A9751C47254 for ; Tue, 5 May 2020 12:17:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 84B8020735 for ; Tue, 5 May 2020 12:17:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728886AbgEEMRz (ORCPT ); Tue, 5 May 2020 08:17:55 -0400 Received: from jabberwock.ucw.cz ([46.255.230.98]:41262 "EHLO jabberwock.ucw.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728819AbgEEMRy (ORCPT ); Tue, 5 May 2020 08:17:54 -0400 Received: by jabberwock.ucw.cz (Postfix, from userid 1017) id 2D53C1C0225; Tue, 5 May 2020 14:17:53 +0200 (CEST) Date: Tue, 5 May 2020 14:17:52 +0200 From: Pavel Machek To: Greg Kroah-Hartman Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, Yan Zhao , Alex Williamson Subject: Re: [PATCH 4.19 21/37] vfio: avoid possible overflow in vfio_iommu_type1_pin_pages Message-ID: <20200505121752.GB28722@amd> References: <20200504165448.264746645@linuxfoundation.org> <20200504165450.604878640@linuxfoundation.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="CUfgB8w4ZwR/yMy5" Content-Disposition: inline In-Reply-To: <20200504165450.604878640@linuxfoundation.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --CUfgB8w4ZwR/yMy5 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon 2020-05-04 19:57:34, Greg Kroah-Hartman wrote: > From: Yan Zhao >=20 > commit 0ea971f8dcd6dee78a9a30ea70227cf305f11ff7 upstream. >=20 > add parentheses to avoid possible vaddr overflow. AFAICT the values are unsigned, so yes, this is nice cleanup, but it does not really fix any problem, right? IOW it overflows, then underflows, but the result is still correct... Best regards, Pavel > Fixes: a54eb55045ae ("vfio iommu type1: Add support for mediated devices") > Signed-off-by: Yan Zhao > Signed-off-by: Alex Williamson > Signed-off-by: Greg Kroah-Hartman >=20 > --- > drivers/vfio/vfio_iommu_type1.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) >=20 > --- a/drivers/vfio/vfio_iommu_type1.c > +++ b/drivers/vfio/vfio_iommu_type1.c > @@ -598,7 +598,7 @@ static int vfio_iommu_type1_pin_pages(vo > continue; > } > =20 > - remote_vaddr =3D dma->vaddr + iova - dma->iova; > + remote_vaddr =3D dma->vaddr + (iova - dma->iova); > ret =3D vfio_pin_page_external(dma, remote_vaddr, &phys_pfn[i], > do_accounting); > if (ret) >=20 --=20 (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo= g.html --CUfgB8w4ZwR/yMy5 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAl6xWXAACgkQMOfwapXb+vK7bQCbBvZQDzcjZdosrXP+fk2XRmmv dtoAoJtNLoHV7yoyx/gKlXEIwkLI2ehi =LUUN -----END PGP SIGNATURE----- --CUfgB8w4ZwR/yMy5--