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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,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 DF7C3C433FF for ; Fri, 2 Aug 2019 09:42:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B71392087E for ; Fri, 2 Aug 2019 09:42:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564738945; bh=QbOzhcvweciA9gWRmPyRlKa3MlVNXQiRlmUhiobmx3I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=sF+y+XjNBQkzmY4unpCgQcYf1y/v2DSFYXx9M6EMFp193wqb06Yzemx0bMBOG+EU8 sEPSeX9tkNJZXvWFdH2zrWOThNSBF8a7gz6k0Dv7k94W/VABrNneX/A2D5bPrAL6Wt 1+pi7l/Z8Wim0pf/QyNk3hEX9dnau+p27j/ejrEM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391859AbfHBJmY (ORCPT ); Fri, 2 Aug 2019 05:42:24 -0400 Received: from mail.kernel.org ([198.145.29.99]:44636 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391528AbfHBJmV (ORCPT ); Fri, 2 Aug 2019 05:42:21 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.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 8E6AD2086A; Fri, 2 Aug 2019 09:42:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564738941; bh=QbOzhcvweciA9gWRmPyRlKa3MlVNXQiRlmUhiobmx3I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Hb9cihbuUa89Xa50BPb2D1LvVjv4h8MpPWundt1odfdN4JHelPEwo1JvfgzE0fq0a lsHQdTTwvweNzxBvZBgcAFrJRJ7f88p5LrWFXnpex+PcZWT0K1FmOKtGaD13JyFIFr SknnVciFqM0lmc02vk9nsl3SXws7Z0yjWgGlEeM0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Weikang shi , Miroslav Lichvar , Thomas Gleixner , John Stultz , Prarit Bhargava , Richard Cochran , Stephen Boyd , Sasha Levin Subject: [PATCH 4.9 047/223] ntp: Limit TAI-UTC offset Date: Fri, 2 Aug 2019 11:34:32 +0200 Message-Id: <20190802092241.975022524@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190802092238.692035242@linuxfoundation.org> References: <20190802092238.692035242@linuxfoundation.org> User-Agent: quilt/0.66 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 [ Upstream commit d897a4ab11dc8a9fda50d2eccc081a96a6385998 ] Don't allow the TAI-UTC offset of the system clock to be set by adjtimex() to a value larger than 100000 seconds. This prevents an overflow in the conversion to int, prevents the CLOCK_TAI clock from getting too far ahead of the CLOCK_REALTIME clock, and it is still large enough to allow leap seconds to be inserted at the maximum rate currently supported by the kernel (once per day) for the next ~270 years, however unlikely it is that someone can survive a catastrophic event which slowed down the rotation of the Earth so much. Reported-by: Weikang shi Signed-off-by: Miroslav Lichvar Signed-off-by: Thomas Gleixner Cc: John Stultz Cc: Prarit Bhargava Cc: Richard Cochran Cc: Stephen Boyd Link: https://lkml.kernel.org/r/20190618154713.20929-1-mlichvar@redhat.com Signed-off-by: Sasha Levin --- kernel/time/ntp.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c index 0a16419006f3..4bdb59604526 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c @@ -42,6 +42,7 @@ static u64 tick_length_base; #define MAX_TICKADJ 500LL /* usecs */ #define MAX_TICKADJ_SCALED \ (((MAX_TICKADJ * NSEC_PER_USEC) << NTP_SCALE_SHIFT) / NTP_INTERVAL_FREQ) +#define MAX_TAI_OFFSET 100000 /* * phase-lock loop variables @@ -639,7 +640,8 @@ static inline void process_adjtimex_modes(struct timex *txc, time_constant = max(time_constant, 0l); } - if (txc->modes & ADJ_TAI && txc->constant >= 0) + if (txc->modes & ADJ_TAI && + txc->constant >= 0 && txc->constant <= MAX_TAI_OFFSET) *time_tai = txc->constant; if (txc->modes & ADJ_OFFSET) -- 2.20.1