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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6BD5DC433FE for ; Mon, 4 Oct 2021 13:38:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 58D8661186 for ; Mon, 4 Oct 2021 13:38:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238435AbhJDNk0 (ORCPT ); Mon, 4 Oct 2021 09:40:26 -0400 Received: from mail.kernel.org ([198.145.29.99]:52272 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238546AbhJDNin (ORCPT ); Mon, 4 Oct 2021 09:38:43 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2E42063244; Mon, 4 Oct 2021 13:17:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1633353466; bh=QP6nuaR1+mibQHUtOSz7uF/n+aPPer/THWb1NdvRCiU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GM28vPJidOfX97HBD3ina9Z+ClR39tWGoQJrbA7w0wP03O7T5QZ5UwvruPnoN7opw nv93O0OORWh5PsW2k7g+Ki6JiI0yL3kM9h2Rvg16P6B9UEE/x62fLo43S//RMXOsy/ 4uLpQFKwMAvhZAzA66DadHhJJ/OCDfQIlYKssFD8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mel Gorman , "Peter Zijlstra (Intel)" , Vincent Guittot , Sasha Levin Subject: [PATCH 5.14 140/172] sched/fair: Null terminate buffer when updating tunable_scaling Date: Mon, 4 Oct 2021 14:53:10 +0200 Message-Id: <20211004125049.493620907@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20211004125044.945314266@linuxfoundation.org> References: <20211004125044.945314266@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Mel Gorman [ Upstream commit 703066188f63d66cc6b9d678e5b5ef1213c5938e ] This patch null-terminates the temporary buffer in sched_scaling_write() so kstrtouint() does not return failure and checks the value is valid. Before: $ cat /sys/kernel/debug/sched/tunable_scaling 1 $ echo 0 > /sys/kernel/debug/sched/tunable_scaling -bash: echo: write error: Invalid argument $ cat /sys/kernel/debug/sched/tunable_scaling 1 After: $ cat /sys/kernel/debug/sched/tunable_scaling 1 $ echo 0 > /sys/kernel/debug/sched/tunable_scaling $ cat /sys/kernel/debug/sched/tunable_scaling 0 $ echo 3 > /sys/kernel/debug/sched/tunable_scaling -bash: echo: write error: Invalid argument Fixes: 8a99b6833c88 ("sched: Move SCHED_DEBUG sysctl to debugfs") Signed-off-by: Mel Gorman Signed-off-by: Peter Zijlstra (Intel) Acked-by: Vincent Guittot Link: https://lore.kernel.org/r/20210927114635.GH3959@techsingularity.net Signed-off-by: Sasha Levin --- kernel/sched/debug.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c index 7e08e3d947c2..2c879cd02a5f 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -173,16 +173,22 @@ static ssize_t sched_scaling_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) { char buf[16]; + unsigned int scaling; if (cnt > 15) cnt = 15; if (copy_from_user(&buf, ubuf, cnt)) return -EFAULT; + buf[cnt] = '\0'; - if (kstrtouint(buf, 10, &sysctl_sched_tunable_scaling)) + if (kstrtouint(buf, 10, &scaling)) return -EINVAL; + if (scaling >= SCHED_TUNABLESCALING_END) + return -EINVAL; + + sysctl_sched_tunable_scaling = scaling; if (sched_update_scaling()) return -EINVAL; -- 2.33.0