From patchwork Tue Nov 5 20:58:36 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ard Biesheuvel X-Patchwork-Id: 11228647 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id EFDA113A4 for ; Tue, 5 Nov 2019 21:11:23 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D6B6D2087E for ; Tue, 5 Nov 2019 21:11:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="HY3pn/Y6"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="eTMYi5yN" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D6B6D2087E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org 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=tdkPCMQ//mQ+Z4fPHAHME2XZ6Jsqsm066E3Dr4X2Ql0=; b=HY3pn/Y6CqxUPW1yMXNdtxi7rp 5iNnvY7rnGZDxm71Jt2dGYjlAKQ76rXl1e6/5GYiMc9XtXNxLaMy9n+Y3IVj29YQ7BUI5JY0l67M5 RqVUDU7FrLI8+L+meIVqAd+Hw5lC1cX57EX4f5CEUQEToktMjY9QrzxQipqDVRmlES+nMm9enxdj2 CdxF/HEZ9rpYMVKzIgnScvTxcmRDg3MUYt0YNn3JXc4i1/JDvMf+hQM/RI/rTWMCyi1E133LIX5PU Q5MB3ZR1OHtyxFSKsf/4vw+xqd5IdT9pCjQ0UiVppjMkUT8Uhax9ok7NOWvnHXopxYxWQBgCw335d ucznt/Cw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1iS66h-0003Mk-86; Tue, 05 Nov 2019 21:11:19 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1iS5wk-0008D4-Qp for linux-arm-kernel@lists.infradead.org; Tue, 05 Nov 2019 21:01:04 +0000 Received: from e123331-lin.home (lfbn-mar-1-643-104.w90-118.abo.wanadoo.fr [90.118.215.104]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C198121D7C; Tue, 5 Nov 2019 21:00:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1572987662; bh=Ij7AZEFGD8uEnpHzLkYxvrY2zmloHlyyapfy5Ifl4ts=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eTMYi5yNbUXG7vdYv3ISNjHuC3o3yWgtwGhNfwsXSYRee/QGltwIBD7rT9r2jrd8K mdexVu07s+A3sGZ9nD3zifC/eu++bwVIzpkCLHVu5NDrPA1SX/rE5bx+aGNKO7vjty mLkKXPqoHk+ZuJ98kUzIaSqvfvYCF0p9kJ/++Wp4= From: Ard Biesheuvel To: linux-arm-kernel@lists.infradead.org Subject: [PATCH for-stable-v4.4 43/53] ARM: 8794/1: uaccess: Prevent speculative use of the current addr_limit Date: Tue, 5 Nov 2019 21:58:36 +0100 Message-Id: <20191105205846.1394-44-ardb@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20191105205846.1394-1-ardb@kernel.org> References: <20191105205846.1394-1-ardb@kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191105_130102_920976_4995BD53 X-CRM114-Status: GOOD ( 11.74 ) X-Spam-Score: -5.2 (-----) X-Spam-Report: SpamAssassin version 3.4.2 on bombadil.infradead.org summary: Content analysis details: (-5.2 points) pts rule name description ---- ---------------------- -------------------------------------------------- -5.0 RCVD_IN_DNSWL_HI RBL: Sender listed at https://www.dnswl.org/, high trust [198.145.29.99 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain -0.0 DKIMWL_WL_HIGH DKIMwl.org - Whitelisted High sender X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Sasha Levin , Florian Fainelli , Julien Thierry , Tony Lindgren , Catalin Marinas , Russell King , "David A . Long" , Marc Zyngier , Will Deacon , Ard Biesheuvel MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.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 Reviewed-by: Julien Thierry Signed-off-by: Sasha Levin Signed-off-by: Ard Biesheuvel --- 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 fd33021da6f6..0404dd101331 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); }