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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 60DABC76191 for ; Mon, 15 Jul 2019 14:42:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3556C205ED for ; Mon, 15 Jul 2019 14:42:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563201766; bh=C4gDV7JcvbE1lcsK7RLAWwtGVBTVpBpoHL1yio2rPVw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=H0ITcZZdH24GdNRGZlDeIOgo8X/XKTVJfmE88awYQZ0rHq+aY9LO1BAA2ED6jM0/W 8cXbo1xjRnVvpQQl4Oiht0/vs8z5U9IVTX1wsXVysOoyPQf/k7m7+wILMP7UWKf+eL YnzlftvW71yGp1WrtwCsVfxGi1QGIhAfhUo6Itqg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391563AbfGOOmn (ORCPT ); Mon, 15 Jul 2019 10:42:43 -0400 Received: from mail.kernel.org ([198.145.29.99]:39606 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404307AbfGOOjf (ORCPT ); Mon, 15 Jul 2019 10:39:35 -0400 Received: from sasha-vm.mshome.net (unknown [73.61.17.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C7E28205ED; Mon, 15 Jul 2019 14:39:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563201574; bh=C4gDV7JcvbE1lcsK7RLAWwtGVBTVpBpoHL1yio2rPVw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=z9mL+stvueIoG+IlbT5bT1rqlhAjrpoJeJFeuAeJPx7VkKTSSY0noVj4Qz0FinDXW uOYPRCizHfsRfv+w843st3nZM53LaloEqS/4jMaH9E0gAwBaZ86oBeOcrSHai9kbUv mW8i7wo3vc/zFf86efXXlhC5OkUQGWAdC3G/L6DA= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Miroslav Lichvar , Weikang shi , Thomas Gleixner , John Stultz , Prarit Bhargava , Richard Cochran , Stephen Boyd , Sasha Levin Subject: [PATCH AUTOSEL 4.9 46/73] ntp: Limit TAI-UTC offset Date: Mon, 15 Jul 2019 10:36:02 -0400 Message-Id: <20190715143629.10893-46-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190715143629.10893-1-sashal@kernel.org> References: <20190715143629.10893-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Miroslav Lichvar [ 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