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=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 73EE6C43381 for ; Mon, 1 Apr 2019 17:31:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4250D2190B for ; Mon, 1 Apr 2019 17:31:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554139872; bh=poRWUDXX0n7reOvnkybxQAfzXXsUTijSOrHVfZD8zsY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=JuJVCgf2x6L8lVr9ghRig/5uA0p/+37uLi4OZofDnnTQRia13dpfiOakymiEtA8XK MPV9+fNmPcv149GQsgbHvdx6J7dDZ2Yu9x7o6ykSAHjCRzaZCN2Zw+KAVVOWxB0B1q 03gD71j6THxDZs03cN6BHS2zQhCRQt+UvN8UFiCw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733227AbfDARbK (ORCPT ); Mon, 1 Apr 2019 13:31:10 -0400 Received: from mail.kernel.org ([198.145.29.99]:38540 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732456AbfDARbI (ORCPT ); Mon, 1 Apr 2019 13:31:08 -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 E392B20856; Mon, 1 Apr 2019 17:31:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554139867; bh=poRWUDXX0n7reOvnkybxQAfzXXsUTijSOrHVfZD8zsY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=G5F4KLKtfVhCxg+kkvlWJ/jurZPdAENK20Fw73yX0Bt0HMHyQP7igUXaO8AmxpFdC m9ulx+tF+2EWiWrN4ftdEWw0id1+fgNOswnJn7i6cspRnV4IlED3mmQYt1sUYneuAn AasMsEl9O8UZJOOwmEdRHR717KPZHvtoVRksFta4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Baolin Wang , Arnd Bergmann , Alexandre Belloni Subject: [PATCH 4.4 036/131] rtc: Fix overflow when converting time64_t to rtc_time Date: Mon, 1 Apr 2019 19:01:46 +0200 Message-Id: <20190401170055.273013163@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190401170051.645954551@linuxfoundation.org> References: <20190401170051.645954551@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore 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 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Baolin Wang commit 36d46cdb43efea74043e29e2a62b13e9aca31452 upstream. If we convert one large time values to rtc_time, in the original formula 'days * 86400' can be overflowed in 'unsigned int' type to make the formula get one incorrect remain seconds value. Thus we can use div_s64_rem() function to avoid this situation. Signed-off-by: Baolin Wang Acked-by: Arnd Bergmann Signed-off-by: Alexandre Belloni Signed-off-by: Arnd Bergmann Signed-off-by: Greg Kroah-Hartman --- drivers/rtc/rtc-lib.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) --- a/drivers/rtc/rtc-lib.c +++ b/drivers/rtc/rtc-lib.c @@ -52,13 +52,11 @@ EXPORT_SYMBOL(rtc_year_days); */ void rtc_time64_to_tm(time64_t time, struct rtc_time *tm) { - unsigned int month, year; - unsigned long secs; + unsigned int month, year, secs; int days; /* time must be positive */ - days = div_s64(time, 86400); - secs = time - (unsigned int) days * 86400; + days = div_s64_rem(time, 86400, &secs); /* day of the week, 1970-01-01 was a Thursday */ tm->tm_wday = (days + 4) % 7;