From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:41004 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753707AbeENHR5 (ORCPT ); Mon, 14 May 2018 03:17:57 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dan Carpenter , "Peter Zijlstra (Intel)" , Linus Torvalds , Thomas Gleixner , Ingo Molnar Subject: [PATCH 4.14 54/62] sched/autogroup: Fix possible Spectre-v1 indexing for sched_prio_to_weight[] Date: Mon, 14 May 2018 08:49:10 +0200 Message-Id: <20180514064819.484188159@linuxfoundation.org> In-Reply-To: <20180514064816.436958006@linuxfoundation.org> References: <20180514064816.436958006@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.14-stable 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 Cc: Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- kernel/sched/autogroup.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/kernel/sched/autogroup.c +++ b/kernel/sched/autogroup.c @@ -7,6 +7,7 @@ #include #include #include +#include unsigned int __read_mostly sysctl_sched_autogroup_enabled = 1; static struct autogroup autogroup_default; @@ -213,7 +214,7 @@ 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; @@ -231,7 +232,9 @@ int proc_sched_autogroup_set_nice(struct next = HZ / 10 + jiffies; ag = autogroup_task_get(p); - shares = scale_load(sched_prio_to_weight[nice + 20]); + + idx = array_index_nospec(nice + 20, 40); + shares = scale_load(sched_prio_to_weight[idx]); down_write(&ag->lock); err = sched_group_set_shares(ag->tg, shares);