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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT 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 24569C3A589 for ; Thu, 15 Aug 2019 15:44:18 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id E350B20665 for ; Thu, 15 Aug 2019 15:44:17 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E350B20665 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id DEB876B02A8; Thu, 15 Aug 2019 11:44:15 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D29256B02AA; Thu, 15 Aug 2019 11:44:15 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C3D0A6B02AB; Thu, 15 Aug 2019 11:44:15 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0084.hostedemail.com [216.40.44.84]) by kanga.kvack.org (Postfix) with ESMTP id 9ECCB6B02A8 for ; Thu, 15 Aug 2019 11:44:15 -0400 (EDT) Received: from smtpin24.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with SMTP id 39B6A4428 for ; Thu, 15 Aug 2019 15:44:15 +0000 (UTC) X-FDA: 75825083670.24.metal47_7c5c81c248742 X-HE-Tag: metal47_7c5c81c248742 X-Filterd-Recvd-Size: 3478 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf43.hostedemail.com (Postfix) with ESMTP for ; Thu, 15 Aug 2019 15:44:14 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 956C81596; Thu, 15 Aug 2019 08:44:13 -0700 (PDT) Received: from arrakis.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id E56B43F706; Thu, 15 Aug 2019 08:44:11 -0700 (PDT) From: Catalin Marinas To: linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org Cc: Andrew Morton , Vincenzo Frascino , Will Deacon , Andrey Konovalov , Szabolcs Nagy , Kevin Brodsky , Dave P Martin , Dave Hansen , linux-doc@vger.kernel.org, linux-arch@vger.kernel.org Subject: [PATCH v8 3/5] arm64: Change the tagged_addr sysctl control semantics to only prevent the opt-in Date: Thu, 15 Aug 2019 16:44:01 +0100 Message-Id: <20190815154403.16473-4-catalin.marinas@arm.com> X-Mailer: git-send-email 2.23.0.rc0 In-Reply-To: <20190815154403.16473-1-catalin.marinas@arm.com> References: <20190815154403.16473-1-catalin.marinas@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: First rename the sysctl control to abi.tagged_addr_disabled and make it default off (zero). When abi.tagged_addr_disabled =3D=3D 1, only block th= e enabling of the TBI ABI via prctl(PR_SET_TAGGED_ADDR_CTRL, PR_TAGGED_ADDR= _ENABLE). Getting the status of the ABI or disabling it is still allowed. Signed-off-by: Catalin Marinas --- arch/arm64/kernel/process.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 76b7c55026aa..03689c0beb34 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -579,17 +579,22 @@ void arch_setup_new_exec(void) /* * Control the relaxed ABI allowing tagged user addresses into the kerne= l. */ -static unsigned int tagged_addr_prctl_allowed =3D 1; +static unsigned int tagged_addr_disabled; =20 long set_tagged_addr_ctrl(unsigned long arg) { - if (!tagged_addr_prctl_allowed) - return -EINVAL; if (is_compat_task()) return -EINVAL; if (arg & ~PR_TAGGED_ADDR_ENABLE) return -EINVAL; =20 + /* + * Do not allow the enabling of the tagged address ABI if globally + * disabled via sysctl abi.tagged_addr_disabled. + */ + if (arg & PR_TAGGED_ADDR_ENABLE && tagged_addr_disabled) + return -EINVAL; + update_thread_flag(TIF_TAGGED_ADDR, arg & PR_TAGGED_ADDR_ENABLE); =20 return 0; @@ -597,8 +602,6 @@ long set_tagged_addr_ctrl(unsigned long arg) =20 long get_tagged_addr_ctrl(void) { - if (!tagged_addr_prctl_allowed) - return -EINVAL; if (is_compat_task()) return -EINVAL; =20 @@ -618,9 +621,9 @@ static int one =3D 1; =20 static struct ctl_table tagged_addr_sysctl_table[] =3D { { - .procname =3D "tagged_addr", + .procname =3D "tagged_addr_disabled", .mode =3D 0644, - .data =3D &tagged_addr_prctl_allowed, + .data =3D &tagged_addr_disabled, .maxlen =3D sizeof(int), .proc_handler =3D proc_dointvec_minmax, .extra1 =3D &zero,