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=-7.0 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 EBAEBC43444 for ; Fri, 28 Dec 2018 12:22:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B50D12070B for ; Fri, 28 Dec 2018 12:22:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1545999733; bh=8Q58KOTrwejcK4f0wPl1jkmNQzh8FhrioIY6JMd6LDc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=IHIxI6J+NqgZqxv79JM30yfEkC2XzSkBeR5W47yYpwFQHTRTMRABbi6qAg8fXoThr jMQaXel7dqjDzxUzUPA7NF4ijvY2RcHAVeSOg2XtiSDk/4Cvmf67cMFeX1RoHgG0eP 20Hs67pCZdyH5o2qAqCL3YEJAzk9dVpb9Zs8nb0I= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732460AbeL1MPc (ORCPT ); Fri, 28 Dec 2018 07:15:32 -0500 Received: from mail.kernel.org ([198.145.29.99]:34544 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732442AbeL1MP3 (ORCPT ); Fri, 28 Dec 2018 07:15:29 -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 61D74218FE; Fri, 28 Dec 2018 12:15:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1545999328; bh=8Q58KOTrwejcK4f0wPl1jkmNQzh8FhrioIY6JMd6LDc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IVP4Ayezitm9OrUC3f83n7EcxYzkYpLRjCqyI3yG8EOBISiLLVSEEuBCy3kf3ekXS 5qPglIoe3YXY5TSMsM6AXkjdounwmoVoR8YvJaGJpmuEq1W5HGY+/QihfP9XTeRx/5 leFKuxGb6G4ayA8651+s6seOsJ8w/qw2U5rwHkQ4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Gustavo A. R. Silva" , Daniel Vetter Subject: [PATCH 4.19 46/46] drm/ioctl: Fix Spectre v1 vulnerabilities Date: Fri, 28 Dec 2018 12:52:40 +0100 Message-Id: <20181228113127.679335146@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20181228113124.971620049@linuxfoundation.org> References: <20181228113124.971620049@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 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Gustavo A. R. Silva commit 505b5240329b922f21f91d5b5d1e535c805eca6d upstream. nr is indirectly controlled by user-space, hence leading to a potential exploitation of the Spectre variant 1 vulnerability. This issue was detected with the help of Smatch: drivers/gpu/drm/drm_ioctl.c:805 drm_ioctl() warn: potential spectre issue 'dev->driver->ioctls' [r] drivers/gpu/drm/drm_ioctl.c:810 drm_ioctl() warn: potential spectre issue 'drm_ioctls' [r] (local cap) drivers/gpu/drm/drm_ioctl.c:892 drm_ioctl_flags() warn: potential spectre issue 'drm_ioctls' [r] (local cap) Fix this by sanitizing nr before using it to index dev->driver->ioctls and drm_ioctls. Notice that given that speculation windows are large, the policy is to kill the speculation on the first load and not worry if it can be completed with a dependent load/store [1]. [1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2 Cc: stable@vger.kernel.org Signed-off-by: Gustavo A. R. Silva Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20181220000015.GA18973@embeddedor Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/drm_ioctl.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) --- a/drivers/gpu/drm/drm_ioctl.c +++ b/drivers/gpu/drm/drm_ioctl.c @@ -37,6 +37,7 @@ #include #include +#include /** * DOC: getunique and setversion story @@ -794,13 +795,17 @@ long drm_ioctl(struct file *filp, if (is_driver_ioctl) { /* driver ioctl */ - if (nr - DRM_COMMAND_BASE >= dev->driver->num_ioctls) + unsigned int index = nr - DRM_COMMAND_BASE; + + if (index >= dev->driver->num_ioctls) goto err_i1; - ioctl = &dev->driver->ioctls[nr - DRM_COMMAND_BASE]; + index = array_index_nospec(index, dev->driver->num_ioctls); + ioctl = &dev->driver->ioctls[index]; } else { /* core ioctl */ if (nr >= DRM_CORE_IOCTL_COUNT) goto err_i1; + nr = array_index_nospec(nr, DRM_CORE_IOCTL_COUNT); ioctl = &drm_ioctls[nr]; } @@ -882,6 +887,7 @@ bool drm_ioctl_flags(unsigned int nr, un if (nr >= DRM_CORE_IOCTL_COUNT) return false; + nr = array_index_nospec(nr, DRM_CORE_IOCTL_COUNT); *flags = drm_ioctls[nr].flags; return true;