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=-7.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 812E6C43441 for ; Wed, 21 Nov 2018 19:11:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4905F214D9 for ; Wed, 21 Nov 2018 19:11:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="puT/BgSk" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4905F214D9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389042AbeKVFrL (ORCPT ); Thu, 22 Nov 2018 00:47:11 -0500 Received: from mail.kernel.org ([198.145.29.99]:42588 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389030AbeKVFrJ (ORCPT ); Thu, 22 Nov 2018 00:47:09 -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 DEAD32151B; Wed, 21 Nov 2018 19:11:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1542827496; bh=KcY7v4pG0KLn+LAyF4TcGZW+AxpciugA3czOiOO8T3U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=puT/BgSkyocglRfnZ4hrlOXGMZGaNaOyGqjjXl6lrL8cWxG/D9qmP9q67EvpBKl6f driKh+HSjGJ+VxGzH86mPmFWAKw/liZNtic3MSbaql8UcRCM5Tr0gt1kZq7hk5Ddpp ykDREvNKYHH/bT3V5Wzzh7NMieeYPcgFTigdp0e4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mark Rutland , Russell King , "David A. Long" Subject: [PATCH 4.9 54/59] ARM: signal: copy registers using __copy_from_user() Date: Wed, 21 Nov 2018 20:07:09 +0100 Message-Id: <20181121183510.426307388@linuxfoundation.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181121183508.262873520@linuxfoundation.org> References: <20181121183508.262873520@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review 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. ------------------ From: Russell King Commit c32cd419d6650e42b9cdebb83c672ec945e6bd7e upstream. __get_user_error() is used as a fast accessor to make copying structure members in the signal handling path as efficient as possible. However, with software PAN and the recent Spectre variant 1, the efficiency is reduced as these are no longer fast accessors. In the case of software PAN, it has to switch the domain register around each access, and with Spectre variant 1, it would have to repeat the access_ok() check for each access. It becomes much more efficient to use __copy_from_user() instead, so let's use this for the ARM integer registers. Acked-by: Mark Rutland Signed-off-by: Russell King Signed-off-by: David A. Long Signed-off-by: Greg Kroah-Hartman --- arch/arm/kernel/signal.c | 38 +++++++++++++++++++++----------------- 1 file changed, 21 insertions(+), 17 deletions(-) --- a/arch/arm/kernel/signal.c +++ b/arch/arm/kernel/signal.c @@ -141,6 +141,7 @@ struct rt_sigframe { static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf) { + struct sigcontext context; struct aux_sigframe __user *aux; sigset_t set; int err; @@ -149,23 +150,26 @@ static int restore_sigframe(struct pt_re if (err == 0) set_current_blocked(&set); - __get_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err); - __get_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err); - __get_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err); - __get_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err); - __get_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err); - __get_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err); - __get_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err); - __get_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err); - __get_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err); - __get_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err); - __get_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err); - __get_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err); - __get_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err); - __get_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err); - __get_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err); - __get_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err); - __get_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err); + err |= __copy_from_user(&context, &sf->uc.uc_mcontext, sizeof(context)); + if (err == 0) { + regs->ARM_r0 = context.arm_r0; + regs->ARM_r1 = context.arm_r1; + regs->ARM_r2 = context.arm_r2; + regs->ARM_r3 = context.arm_r3; + regs->ARM_r4 = context.arm_r4; + regs->ARM_r5 = context.arm_r5; + regs->ARM_r6 = context.arm_r6; + regs->ARM_r7 = context.arm_r7; + regs->ARM_r8 = context.arm_r8; + regs->ARM_r9 = context.arm_r9; + regs->ARM_r10 = context.arm_r10; + regs->ARM_fp = context.arm_fp; + regs->ARM_ip = context.arm_ip; + regs->ARM_sp = context.arm_sp; + regs->ARM_lr = context.arm_lr; + regs->ARM_pc = context.arm_pc; + regs->ARM_cpsr = context.arm_cpsr; + } err |= !valid_user_regs(regs);