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=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 5D6B1C43381 for ; Tue, 26 Mar 2019 06:45:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 213582075E for ; Tue, 26 Mar 2019 06:45:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553582724; bh=wxXsOBgbbz5sskrOIIZhogfOxRdv57I7U8CxZCrvQSE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=sEZeyoLhbUmD2vNJ6G5ujjWLqG3sy9FqO5PJWm9vEruAtTxjMaJXsvHVfVVXEvUZB mGxztiGGyOtW0dNet4jPu1Nu7Av9EeOytx9CK0We1Y+O0aQw9bxvXBxvBOboZ2pJxp kf/IK7E61CQjDb5wW1cvfN6HDFQZwm/xiKlUzvvM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731896AbfCZGef (ORCPT ); Tue, 26 Mar 2019 02:34:35 -0400 Received: from mail.kernel.org ([198.145.29.99]:45252 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731869AbfCZGee (ORCPT ); Tue, 26 Mar 2019 02:34:34 -0400 Received: from localhost (unknown [104.132.152.111]) (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 0E00D2086C; Tue, 26 Mar 2019 06:34:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553582073; bh=wxXsOBgbbz5sskrOIIZhogfOxRdv57I7U8CxZCrvQSE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=x9RQJ8ZqpzBxPAuvbIlyag0YIjx/jxhR3BoluF60bdzaKcwqLN9/GY+WRweGC0zD0 gaDN6xZR/2Up1jkspkxn+a9TbhiJPOQBLquZhrt1V2h037KH/zk1TNG4HmbQa5cjYq zxNlmKROJXk6RcyfeZxTfU8V3UMVTSS+1IGGtI/w= 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 4.14 37/41] rtc: Fix overflow when converting time64_t to rtc_time Date: Tue, 26 Mar 2019 15:30:14 +0900 Message-Id: <20190326042651.912300536@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190326042649.889479098@linuxfoundation.org> References: <20190326042649.889479098@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: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 4.14-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;