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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,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 85019C10F01 for ; Mon, 18 Feb 2019 14:30:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4D2812081B for ; Mon, 18 Feb 2019 14:30:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550500258; bh=VPif0orIIULkZew+r4PMJnLlAMk0GDxGSY02UuR/K/I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=OYmxE/jaszYgvTmAih4QTUj0V9YAJK3wqMmvOrbv+V9vP4j/E8bbeSZS+7azn6v5f bkZ/0leUSyUy9jtDidzW1oFCpyIJAi8WGkLsCLoaF8fJAgfGqCDRzAZTPZDqnoLKOz obeGyARms2R7CtyLX+JJLIsKx2NB/Lk1NYT8Gpi4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388337AbfBRN6X (ORCPT ); Mon, 18 Feb 2019 08:58:23 -0500 Received: from mail.kernel.org ([198.145.29.99]:38992 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388310AbfBRN6T (ORCPT ); Mon, 18 Feb 2019 08:58:19 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9CDE021901; Mon, 18 Feb 2019 13:58:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550498298; bh=VPif0orIIULkZew+r4PMJnLlAMk0GDxGSY02UuR/K/I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=konenjjg2Gyr8kQnBN0J7wXw1+vB58tZecoyksh+z8VGVBBGKd11VdFQhTTjICfnt KrZuP402C+rcTMRCLklqs8SzIDzlh31K/1JUaO8Sr83yGb4mB67f6JQ1d5fRlR2VvD Z2wR1iw1e6lGhUKzmGGq+htN+qW1UnoetZP9jVVk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Julien Thierry , Russell King , "David A. Long" , Sasha Levin Subject: [PATCH 4.9 08/58] ARM: 8794/1: uaccess: Prevent speculative use of the current addr_limit Date: Mon, 18 Feb 2019 14:43:29 +0100 Message-Id: <20190218133509.231691321@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190218133508.567416115@linuxfoundation.org> References: <20190218133508.567416115@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ 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 Reviewed-by: Julien Thierry Signed-off-by: Sasha Levin --- 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 7b17460127fd..9ae888775743 100644 --- a/arch/arm/include/asm/uaccess.h +++ b/arch/arm/include/asm/uaccess.h @@ -99,6 +99,14 @@ 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); } -- 2.19.1