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=-9.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 AEFDCC43381 for ; Wed, 13 Feb 2019 21:33:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7E983206C0 for ; Wed, 13 Feb 2019 21:33:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="gQABb81M" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2436775AbfBMVck (ORCPT ); Wed, 13 Feb 2019 16:32:40 -0500 Received: from mail-qt1-f193.google.com ([209.85.160.193]:34969 "EHLO mail-qt1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2436736AbfBMVcf (ORCPT ); Wed, 13 Feb 2019 16:32:35 -0500 Received: by mail-qt1-f193.google.com with SMTP id p48so4495707qtk.2 for ; Wed, 13 Feb 2019 13:32:34 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=dQLK2/rrLChjZCacrkpff81URBJeOtphw+yxRdVdzZ4=; b=gQABb81MbKQBlmSXhqJWQfg/1AxyC7N9oosWf++hMdAGIruAgpqJYldwUqM1bmB6Jr dulsq1OpTXHG1i2jGcQeuZyZIpjlKNdKfSMyrS0u+NAnjSlxqj7zZ3qkDJYNjUsmUrJF zigsHfdtmvf3MT0gwEA2vuSBKY4RwNgfY025WHBxSsYe2wuncmOQ88OE0GyPQcL58ysd 4e65OoRDhrMM69gcPZUaLEQEaHinHgZEFhvilAAmkSckKd5/7GedCqUALyP0aiq2Fvxn HNIc7JEQhrKke9sonMbxjJlaZ3nPYoqJqcssm1/sMCPDAFExEk7IVkLGZUSwo359avMR lWKQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=dQLK2/rrLChjZCacrkpff81URBJeOtphw+yxRdVdzZ4=; b=bi2w7uZEG7k6hNM2rU29fdy/ClZbdMwqiiwY+lUMlooZT5PejDZv9l1y6fWwDqHemq T2AiHNC3jGsaC8f3rFdOvbYU9eOCvWWckkBTaA/2+UvdRdrCiIjhKBAEmvpFNJGXFfxz i8WXhJ59Qbtiel3pLTLq428enl5z2zHrAzLYW59+D3HMnW9qKsuOwgS8wL2e8Hz6I2Xy T+ATRc05OX6u/OXa0JMh2beE5hhSgh8KZSAUofu0C1AnZ1wjvid3hktEeGUc1G+1SYt2 1lZaMFia1J1Sn5kjGhr5LQpu1yxAxUOHfKT4OCqgeUKKRQk5asl4NcfEt8yHjSgrr5bB /r4g== X-Gm-Message-State: AHQUAua6m67NEe3sFtRaVNQFkr8R8tVyiPycN+bbAkF5Odm1VggmnKGl flhUtw3QSJjQkLCn7LZWvTOK2g== X-Google-Smtp-Source: AHgI3Ia4pComQ8ctgxQDJ1CcQxaos+nBxL2y9DAGiemotoOFbJLoJ3KztZyURL89wAh+dQrfdS0EKQ== X-Received: by 2002:ac8:341a:: with SMTP id u26mr205865qtb.211.1550093554162; Wed, 13 Feb 2019 13:32:34 -0800 (PST) Received: from localhost.localdomain (pool-72-71-243-63.cncdnh.fast00.myfairpoint.net. [72.71.243.63]) by smtp.googlemail.com with ESMTPSA id 8sm382675qtr.7.2019.02.13.13.32.32 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 13 Feb 2019 13:32:33 -0800 (PST) From: David Long To: stable@vger.kernel.org, Russell King - ARM Linux , Florian Fainelli , Julien Thierry , Tony Lindgren , Marc Zyngier , Greg KH , Mark Rutland Cc: Will Deacon , Mark Brown , linux-kernel@vger.kernel.org Subject: [PATCH 4.19 06/17] ARM: 8794/1: uaccess: Prevent speculative use of the current addr_limit Date: Wed, 13 Feb 2019 16:32:12 -0500 Message-Id: <20190213213223.916-7-dave.long@linaro.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190213213223.916-1-dave.long@linaro.org> References: <20190213213223.916-1-dave.long@linaro.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Julien Thierry Commit 621afc677465db231662ed126ae1f355bf8eac47 upstream. A mispredicted conditional call to set_fs could result in the wrong addr_limit being forwarded under speculation to a subsequent access_ok check, potentially forming part of a spectre-v1 attack using uaccess routines. This patch prevents this forwarding from taking place, but putting heavy barriers in set_fs after writing the addr_limit. Porting commit c2f0ad4fc089cff8 ("arm64: uaccess: Prevent speculative use of the current addr_limit"). Signed-off-by: Julien Thierry Signed-off-by: Russell King Signed-off-by: David A. Long --- arch/arm/include/asm/uaccess.h | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h index 5451e1f05a19..d65ef85fc617 100644 --- a/arch/arm/include/asm/uaccess.h +++ b/arch/arm/include/asm/uaccess.h @@ -69,6 +69,14 @@ extern int __put_user_bad(void); static inline void set_fs(mm_segment_t fs) { current_thread_info()->addr_limit = fs; + + /* + * Prevent a mispredicted conditional call to set_fs from forwarding + * the wrong address limit to access_ok under speculation. + */ + dsb(nsh); + isb(); + modify_domain(DOMAIN_KERNEL, fs ? DOMAIN_CLIENT : DOMAIN_MANAGER); } -- 2.17.1