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=-7.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,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 DF5FBC43381 for ; Wed, 27 Feb 2019 08:13:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AEE7B218E0 for ; Wed, 27 Feb 2019 08:13:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=yandex-team.ru header.i=@yandex-team.ru header.b="QChFQyWQ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729654AbfB0IN0 (ORCPT ); Wed, 27 Feb 2019 03:13:26 -0500 Received: from forwardcorp1o.cmail.yandex.net ([37.9.109.47]:56349 "EHLO forwardcorp1o.cmail.yandex.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726925AbfB0INZ (ORCPT ); Wed, 27 Feb 2019 03:13:25 -0500 Received: from mxbackcorp1o.mail.yandex.net (mxbackcorp1o.mail.yandex.net [IPv6:2a02:6b8:0:1a2d::301]) by forwardcorp1o.cmail.yandex.net (Yandex) with ESMTP id 3D4EA219F2; Wed, 27 Feb 2019 11:13:22 +0300 (MSK) Received: from smtpcorp1p.mail.yandex.net (smtpcorp1p.mail.yandex.net [2a02:6b8:0:1472:2741:0:8b6:10]) by mxbackcorp1o.mail.yandex.net (nwsmtp/Yandex) with ESMTP id gvbECA5d0a-DLhKaDMa; Wed, 27 Feb 2019 11:13:22 +0300 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yandex-team.ru; s=default; t=1551255202; bh=8kFu2wWh3Op+B8NZK/FPFrEnAAthfynrTJBN0YQ9dko=; h=Message-ID:Date:To:From:Subject; b=QChFQyWQRPml22HfRer0LqfEssiFGUcpS1KWe5R0TIdlZuGFWNRKKj56z9MhhdZXt Zd+DrubbdYyyqGmvyngmLnkwfAP4CcG/3cAK5wAtuyqVojB77JYtHHqk4pYxpRMr0x cHn31V4Ku8OwHCDGPQQjuQSDXj2R6508Qb/v2HBk= Authentication-Results: mxbackcorp1o.mail.yandex.net; dkim=pass header.i=@yandex-team.ru Received: from dynamic-red.dhcp.yndx.net (dynamic-red.dhcp.yndx.net [2a02:6b8:0:40c:8865:6f76:e76b:3fab]) by smtpcorp1p.mail.yandex.net (nwsmtp/Yandex) with ESMTPSA id 7MJk1IpqI3-DLo8IeCV; Wed, 27 Feb 2019 11:13:21 +0300 (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client certificate not present) Subject: [PATCH] sched/core: check format and overflows in cgroup2 cpu.max From: Konstantin Khlebnikov To: Peter Zijlstra , linux-kernel@vger.kernel.org, Li Zefan , Johannes Weiner , Tejun Heo , cgroups@vger.kernel.org, Ingo Molnar Date: Wed, 27 Feb 2019 11:13:21 +0300 Message-ID: <155125520155.293746.7017401430432481979.stgit@buzz> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Cgroup2 interface for cpu bandwidth limit has some flaws: - on stack buffer overflow - no checks for valid format or trailing garbage - no checks for integer overflows This patch fixes all these flaws. Fixes: 0d5936344f30 ("sched: Implement interface for cgroup unified hierarchy") Signed-off-by: Konstantin Khlebnikov --- kernel/sched/core.c | 29 ++++++++++++++++++++++------- 1 file changed, 22 insertions(+), 7 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 5f46aa335b28..123b1910bc2e 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -6947,19 +6947,34 @@ static int __maybe_unused cpu_period_quota_parse(char *buf, u64 *periodp, u64 *quotap) { char tok[21]; /* U64_MAX */ + int ret, len; - if (!sscanf(buf, "%s %llu", tok, periodp)) + if (sscanf(buf, "%20s %n", tok, &len) != 1) return -EINVAL; - *periodp *= NSEC_PER_USEC; - - if (sscanf(tok, "%llu", quotap)) - *quotap *= NSEC_PER_USEC; - else if (!strcmp(tok, "max")) + ret = kstrtou64(tok, 10, quotap); + if (ret) { + if (strcmp(tok, "max")) + return ret; *quotap = RUNTIME_INF; - else + } else if (*quotap <= U64_MAX / NSEC_PER_USEC) { + *quotap *= NSEC_PER_USEC; + } else return -EINVAL; + buf += len; + if (*buf) { + if (sscanf(buf, "%20s %n", tok, &len) != 1 || buf[len]) + return -EINVAL; + ret = kstrtou64(tok, 10, periodp); + if (ret) + return ret; + if (*periodp > U64_MAX / NSEC_PER_USEC) + return -EINVAL; + } + + *periodp *= NSEC_PER_USEC; + return 0; }