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,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 0030BC43381 for ; Mon, 18 Feb 2019 14:00:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C1A73217D9 for ; Mon, 18 Feb 2019 14:00:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550498443; bh=XseDgABFK0MywURQvbsVaEKSJIwmD7RKkT0XRJWLpQ0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Vt41KG1qYTuqJrl7WHdr7TE0V7HBIool4lgqhRkLPpNnaBENAIdv8vY4XAq8Iqdkb NM0YZoVPmp8n6oToVwCmi4fqriL5Gyvil6taZBcI4O2ksdHmZezhG1NCZ/zDGGJYWH NPy04UQzZQatA0/TAVoIso9vfuEuJcrfxRB+92EM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388889AbfBROAm (ORCPT ); Mon, 18 Feb 2019 09:00:42 -0500 Received: from mail.kernel.org ([198.145.29.99]:41914 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388870AbfBROAi (ORCPT ); Mon, 18 Feb 2019 09:00:38 -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 8D6DF21902; Mon, 18 Feb 2019 14:00:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550498438; bh=XseDgABFK0MywURQvbsVaEKSJIwmD7RKkT0XRJWLpQ0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RySgQwkdB4h90tIi27t2d3QNwAuD9nj/QHrE/vpVdnYA6bORLqPGXA0s2u9ZNyS9A VZpAc0j3Vugvk1O1XH7e8YGDYyGK5zL39ScOIgW5+RB9E33hr9S2kR1rJ/So74BucU Anrs7sPEYzyiqEi0C6ydkyFmstTuVCbO1GyuWNdw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Gustavo A. R. Silva" , Daniel Vetter , Sasha Levin Subject: [PATCH 4.4 001/143] drm/bufs: Fix Spectre v1 vulnerability Date: Mon, 18 Feb 2019 14:42:09 +0100 Message-Id: <20190218133529.159747802@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190218133529.099444112@linuxfoundation.org> References: <20190218133529.099444112@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 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ [ Upstream commit a37805098900a6e73a55b3a43b7d3bcd987bb3f4 ] idx can be 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_bufs.c:1420 drm_legacy_freebufs() warn: potential spectre issue 'dma->buflist' [r] (local cap) Fix this by sanitizing idx before using it to index dma->buflist 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 Signed-off-by: Gustavo A. R. Silva Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20181016095549.GA23586@embeddedor.com Signed-off-by: Sasha Levin --- drivers/gpu/drm/drm_bufs.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/gpu/drm/drm_bufs.c b/drivers/gpu/drm/drm_bufs.c index f1a204d253cc..ac22b8d86249 100644 --- a/drivers/gpu/drm/drm_bufs.c +++ b/drivers/gpu/drm/drm_bufs.c @@ -36,6 +36,8 @@ #include #include "drm_legacy.h" +#include + static struct drm_map_list *drm_find_matching_map(struct drm_device *dev, struct drm_local_map *map) { @@ -1332,6 +1334,7 @@ int drm_legacy_freebufs(struct drm_device *dev, void *data, idx, dma->buf_count - 1); return -EINVAL; } + idx = array_index_nospec(idx, dma->buf_count); buf = dma->buflist[idx]; if (buf->file_priv != file_priv) { DRM_ERROR("Process %d freeing buffer not owned\n", -- 2.19.1