From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751324AbeDWFBT (ORCPT ); Mon, 23 Apr 2018 01:01:19 -0400 Received: from mout.web.de ([212.227.17.11]:42577 "EHLO mout.web.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751165AbeDWFBQ (ORCPT ); Mon, 23 Apr 2018 01:01:16 -0400 Subject: Re: BUG: KASAN: global-out-of-bounds in unmap_kernel_at_el0+0x70/0x1a0 To: Mark Rutland Cc: linux-arm-kernel , Linux Kernel Mailing List , will.deacon@arm.com, catalin.marinas@arm.com, suzuki.poulose@arm.com References: <97d99ad9-c5cf-a4d2-126a-2b39ffead0b3@web.de> <20180422190639.lyfvgnzapo2mrpu6@salmiak> From: Jan Kiszka Openpgp: preference=signencrypt Message-ID: Date: Mon, 23 Apr 2018 07:00:52 +0200 User-Agent: Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 MIME-Version: 1.0 In-Reply-To: <20180422190639.lyfvgnzapo2mrpu6@salmiak> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="1znVi35YNlXXPoj81qE88oRx1RIUVv66s" X-Provags-ID: V03:K1:78Lq1xa/n4ByMluUd2uabW6TVj64GJkw5ziSVT6IJ1SGahNxyw7 SJ33wfgboUPrhpwwFhkAd/cKI6hRHdMpF+xsWkX/GIyJbSgC/nMrBGmLsHM17Bw0VmoPSWe 7qkNb3n7vg+l+LE32TO+rzzRSicM4pdHjOhl2TXBvUGotYNPImbtjVmRuv0DZ/iuK4tRv8z ieZ0aNduwCDQp1Ux+veHg== X-UI-Out-Filterresults: notjunk:1;V01:K0:zZLs8TW0KsY=:X5tlPz1u/PlqqlgRPGnzOR d08zmIxV1anl5KL23btaN66+5gtiz+xS678y8teOnDzDN3MCDpKqQZ6RRPoBUgnudiHL7rokt 79DjlltLmS6JRpsmlMzmcXYzAmrC97X63LyRCm2vWWujpSjcMrgzBK2agoi477M1LIfc5oSau jnLfQIzLhsnHl5WsUHm6BB+7lEXA7qVld+0tHwDX1PHebw37ckT0H1nedlNLeH7XJfRz+aJVB lC+F9/yvt2EVfAASn3W39EHLFjGNiaMwuM3/YHITg4/USGsrIJjYjaJ8mr/ePpWIqtcJpbvgJ suNQJvNQayvZQjYO12h7U/R6pepEmJDSXzYV3EGPsnDitHCQAtGCyO2AnDgJgoikr1Y1c2W38 bnbJMpLupT/HYx7KXgD95KBa2pUmE5l/b5JSJfumCBFE0YigIoIxrkh3SlzfXQ0BKvZs6fBOH RcXLn9+tEmIcPhQ/vkcaKWklGK+RT2ZZU9vKeqZZvbkL+HAgjodXQurYL0KnDBkOCebDR+zkN tmjREllzj+qLX+dApY/BY3PtME7yPguGO82r9bANW8Y2MNjmCNWUxGD7Yn5rg10G05pSd68Va vDr1qcdVjv1DTwPrF99ZG2B03q16Paxsx0TbWm35V4uLoD0Hf1buHhlOJZ/a4My8mV0WHUIMr 5L7f44pMve69E7n1YeiNqVoAHfavaBcGzhtkP5oyQNFDRUJ07VOxio+f2YpvKYlRF/aJsc4JE 4BZudcjORuNTjDH5zFLZOFBUkqZdac6MvI5oQm6Kmdyu0sv5pjvEiE3mW2asdxpQgB9dpsQXJ /lpfdMvyrH46ZSjB/TAkjMRdVEfqA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --1znVi35YNlXXPoj81qE88oRx1RIUVv66s Content-Type: multipart/mixed; boundary="qsHzwwEy6FMnoJpN4grxAcEljmoBcuKwt"; protected-headers="v1" From: Jan Kiszka To: Mark Rutland Cc: linux-arm-kernel , Linux Kernel Mailing List , will.deacon@arm.com, catalin.marinas@arm.com, suzuki.poulose@arm.com Message-ID: Subject: Re: BUG: KASAN: global-out-of-bounds in unmap_kernel_at_el0+0x70/0x1a0 References: <97d99ad9-c5cf-a4d2-126a-2b39ffead0b3@web.de> <20180422190639.lyfvgnzapo2mrpu6@salmiak> In-Reply-To: <20180422190639.lyfvgnzapo2mrpu6@salmiak> --qsHzwwEy6FMnoJpN4grxAcEljmoBcuKwt Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 2018-04-22 21:06, Mark Rutland wrote: > On Sun, Apr 22, 2018 at 12:47:57PM +0200, Jan Kiszka wrote: >> Hi, >> >> this can be triggered simply by running >> >> # echo 0 > /sys/devices/system/cpu/cpu3/online >> # echo 1 > /sys/devices/system/cpu/cpu3/online >> >> [ 455.904854] =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D >> [ 455.906108] BUG: KASAN: global-out-of-bounds in unmap_kernel_at_el0= +0x70/0x1a0 >> [ 455.906668] Read of size 4 at addr ffff200008e3a9d8 by task swapper= /3/0 >=20 > It looks like we miss a sentinel in kpti_safe_list. >=20 > Does the below help? >=20 > Mark. >=20 > ---->8---- > From ade322407e3d6d1f50e558ebd50d2c1c7bd811c2 Mon Sep 17 00:00:00 2001 > From: Mark Rutland > Date: Sun, 22 Apr 2018 19:58:08 +0100 > Subject: [PATCH] arm64: add sentinel to kpti_safe_list >=20 > We're missing a sentinel entry in kpti_safe_list. Thus is_midr_in_range= _list() > can walk past the end of kpti_safe_list. Depending on the contents of m= emory, > this could erroneously match a CPU's MIDR, cause a data abort, or other= bad > outcomes. >=20 > Add the sentinel entry to avoid this. >=20 > Fixes: be5b299830c63ed7 ("arm64: capabilities: Add support for checks b= ased on a list of MIDRs") > Signed-off-by: Mark Rutland > Reported-by: Jan Kiszka > Cc: Catalin Marinas > Cc: Suzuki K Poulose > Cc: Will Deacon > --- > arch/arm64/kernel/cpufeature.c | 1 + > 1 file changed, 1 insertion(+) >=20 > diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeat= ure.c > index 536d572e5596..9d1b06d67c53 100644 > --- a/arch/arm64/kernel/cpufeature.c > +++ b/arch/arm64/kernel/cpufeature.c > @@ -868,6 +868,7 @@ static bool unmap_kernel_at_el0(const struct arm64_= cpu_capabilities *entry, > static const struct midr_range kpti_safe_list[] =3D { > MIDR_ALL_VERSIONS(MIDR_CAVIUM_THUNDERX2), > MIDR_ALL_VERSIONS(MIDR_BRCM_VULCAN), > + { /* sentinel */ } > }; > char const *str =3D "command line option"; > =20 >=20 Jep, all fine now! Jan --qsHzwwEy6FMnoJpN4grxAcEljmoBcuKwt-- --1znVi35YNlXXPoj81qE88oRx1RIUVv66s Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iEYEARECAAYFAlrdaIkACgkQitSsb3rl5xRgsACgz7U4Wz1oLfh+pmR+RsCDN265 cOMAn0wAHoX0XzmD8xZqLeBICXy5GUR+ =0BMj -----END PGP SIGNATURE----- --1znVi35YNlXXPoj81qE88oRx1RIUVv66s--