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=-9.0 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,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 C1387C169C4 for ; Mon, 11 Feb 2019 14:20:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 910FC21B24 for ; Mon, 11 Feb 2019 14:20:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1549894851; bh=WYPSYzdLZ5ZsN1ieUok+VanCLX9cEhUwhiLFNcBm6eQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=j7kQeMUYh3c5Y0lL/A8tRGHyC0fM9RjeFlHaZTQA3Y2svBo5D9XTms3ge4rNMygqd 1o/ShjAz++QxElvrQmUes4oqUare9F5yJRcmKwAbV4xodd8qMMn4osB2G1++axgABn kmmP74SuKOUkwAwR5jUx20KbEtOWyLkZs064DJmU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728385AbfBKOUu (ORCPT ); Mon, 11 Feb 2019 09:20:50 -0500 Received: from mail.kernel.org ([198.145.29.99]:53584 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726796AbfBKOUt (ORCPT ); Mon, 11 Feb 2019 09:20:49 -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 5374520838; Mon, 11 Feb 2019 14:20:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1549894848; bh=WYPSYzdLZ5ZsN1ieUok+VanCLX9cEhUwhiLFNcBm6eQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=D0y93m75qnZXKcz60jGTt0OAXFAJRzWb3ghE3VWypg7H7Cp167tNezuGqQOTWjLdM EykoV6F9edpzbZjJWo6FS1DL0iWMyLZM/hPabIsmaM5pQ7TVoL49hpNLZWl5V/DFTW Y2nQ3f4776ekXsTpxQAqu+Q0b2No7r3TIm4g0U78= 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 4.20 001/352] drm/bufs: Fix Spectre v1 vulnerability Date: Mon, 11 Feb 2019 15:13:48 +0100 Message-Id: <20190211141846.622069821@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190211141846.543045703@linuxfoundation.org> References: <20190211141846.543045703@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 4.20-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 7412acaf3cde..d7d10cabb9bb 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) { @@ -1417,6 +1419,7 @@ 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