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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 F244CC7112A for ; Sun, 14 Oct 2018 15:40:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B675B20645 for ; Sun, 14 Oct 2018 15:40:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B675B20645 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=decadent.org.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728217AbeJNXVt (ORCPT ); Sun, 14 Oct 2018 19:21:49 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:36250 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728094AbeJNXMC (ORCPT ); Sun, 14 Oct 2018 19:12:02 -0400 Received: from [2a02:8011:400e:2:cbab:f00:c93f:614] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.84_2) (envelope-from ) id 1gBiLq-0004cU-62; Sun, 14 Oct 2018 16:30:42 +0100 Received: from ben by deadeye with local (Exim 4.91) (envelope-from ) id 1gBiLX-0000WJ-ED; Sun, 14 Oct 2018 16:30:23 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Dan Carpenter" , "Thomas Gleixner" , "Peter Zijlstra" , "Linus Torvalds" , "Ingo Molnar" Date: Sun, 14 Oct 2018 16:25:41 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 263/366] sched/autogroup: Fix possible Spectre-v1 indexing for sched_prio_to_weight[] In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:cbab:f00:c93f:614 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.60-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Peter Zijlstra commit 354d7793070611b4df5a79fbb0f12752d0ed0cc5 upstream. > kernel/sched/autogroup.c:230 proc_sched_autogroup_set_nice() warn: potential spectre issue 'sched_prio_to_weight' Userspace controls @nice, sanitize the array index. Reported-by: Dan Carpenter Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Ingo Molnar [bwh: Backported to 3.16: adjust filename, context] Signed-off-by: Ben Hutchings --- kernel/sched/auto_group.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/kernel/sched/auto_group.c +++ b/kernel/sched/auto_group.c @@ -8,6 +8,7 @@ #include #include #include +#include unsigned int __read_mostly sysctl_sched_autogroup_enabled = 1; static struct autogroup autogroup_default; @@ -198,7 +199,7 @@ int proc_sched_autogroup_set_nice(struct static unsigned long next = INITIAL_JIFFIES; struct autogroup *ag; unsigned long shares; - int err; + int err, idx; if (nice < MIN_NICE || nice > MAX_NICE) return -EINVAL; @@ -216,7 +217,9 @@ int proc_sched_autogroup_set_nice(struct next = HZ / 10 + jiffies; ag = autogroup_task_get(p); - shares = scale_load(prio_to_weight[nice + 20]); + + idx = array_index_nospec(nice + 20, 40); + shares = scale_load(prio_to_weight[idx]); down_write(&ag->lock); err = sched_group_set_shares(ag->tg, shares);