From patchwork Thu Aug 9 15:26:36 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Julien Thierry X-Patchwork-Id: 10561541 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C2B1B1515 for ; Thu, 9 Aug 2018 15:27:38 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9DDA82B5BE for ; Thu, 9 Aug 2018 15:27:38 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 90F8E2B5E3; Thu, 9 Aug 2018 15:27:38 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 3FB1E2B5CF for ; Thu, 9 Aug 2018 15:27:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:References: In-Reply-To:Message-Id:Date:Subject:To:From:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=nRPcETbZ+ZGilByewNcWl1/9KwNbHwBnJ3G6WU62C7k=; b=bVaR6i48YohsVC+JG2SBtN6qmv gxomSTweZFQrfCF92zAA2uolmgwIysYfpQCroH4CyANDtmTK8rNuKFEcjHDbACpgn72NEiA6GfBoV +rLHfXeCHJZVj5p+QVkes9eHJjBBpmukEP8Fj9S88eA+3CW0Y1L/Rheynb8X2b+5uiV2SlycjlSwV MPZu2wgcU67viT6jc05tSHiHoM8NKv7zy9xkXfLvh+X35TRPZ0liVOUracK4ehuAKBOXtHMyboiC7 NruIrutsdmyEF59M7qzQ2Fq6EYz7PtjCsGApeGJYIsxvNAEJV1RzuZCSlBSGqR0NGDxAaYqMu51QQ b158WOqQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1fnmqe-0002tT-3A; Thu, 09 Aug 2018 15:27:36 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1fnmq7-0002DX-3p for linux-arm-kernel@lists.infradead.org; Thu, 09 Aug 2018 15:27:05 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id E12ACED1; Thu, 9 Aug 2018 08:26:51 -0700 (PDT) Received: from e112298-lin.Emea.Arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id D351C3F5B3; Thu, 9 Aug 2018 08:26:50 -0700 (PDT) From: Julien Thierry To: linux-arm-kernel@lists.infradead.org Subject: [PATCH 1/8] ARM: uaccess: Prevent speculative use of the current addr_limit Date: Thu, 9 Aug 2018 16:26:36 +0100 Message-Id: <1533828403-21323-2-git-send-email-julien.thierry@arm.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1533828403-21323-1-git-send-email-julien.thierry@arm.com> References: <1533828403-21323-1-git-send-email-julien.thierry@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20180809_082703_180554_019F39D8 X-CRM114-Status: GOOD ( 11.49 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.rutland@arm.com, will.deacon@arm.com, linux@armlinux.org.uk, Julien Thierry MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP 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 Cc: Russell King --- arch/arm/include/asm/uaccess.h | 8 ++++++++ 1 file changed, 8 insertions(+) -- 1.9.1 diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h index 5451e1f..d65ef85 100644 --- a/arch/arm/include/asm/uaccess.h +++ b/arch/arm/include/asm/uaccess.h @@ -69,6 +69,14 @@ static inline void uaccess_restore(unsigned int flags) 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); }