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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,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 D7772C169C4 for ; Wed, 6 Feb 2019 10:31:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E3F2B206C2 for ; Wed, 6 Feb 2019 10:31:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729184AbfBFKbF (ORCPT ); Wed, 6 Feb 2019 05:31:05 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:49043 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726728AbfBFKbF (ORCPT ); Wed, 6 Feb 2019 05:31:05 -0500 Received: from 1.general.cking.uk.vpn ([10.172.193.212] helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.76) (envelope-from ) id 1grKTu-0002JW-Hb; Wed, 06 Feb 2019 10:31:02 +0000 From: Colin King To: Alessandro Zummo , Alexandre Belloni , linux-rtc@vger.kernel.org Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] rtc: pm8xxx: fix unintended sign extension Date: Wed, 6 Feb 2019 10:31:02 +0000 Message-Id: <20190206103102.19345-1-colin.king@canonical.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Sender: linux-rtc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rtc@vger.kernel.org From: Colin Ian King Shifting a u8 by 24 will cause the value to be promoted to an integer. If the top bit of the u8 is set then the following conversion to an unsigned long will sign extend the value causing the upper 32 bits to be set in the result. Fix this by casting the u8 value to an unsigned long before the shift. Detected by CoverityScan, CID#1309693 ("Unintended sign extension") Fixes: 9a9a54ad7aa2 ("drivers/rtc: add support for Qualcomm PMIC8xxx RTC") Signed-off-by: Colin Ian King --- drivers/rtc/rtc-pm8xxx.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/rtc/rtc-pm8xxx.c b/drivers/rtc/rtc-pm8xxx.c index 1074e3dbfc1d..cda020700744 100644 --- a/drivers/rtc/rtc-pm8xxx.c +++ b/drivers/rtc/rtc-pm8xxx.c @@ -213,7 +213,8 @@ static int pm8xxx_rtc_read_time(struct device *dev, struct rtc_time *tm) } } - secs = value[0] | (value[1] << 8) | (value[2] << 16) | (value[3] << 24); + secs = value[0] | (value[1] << 8) | (value[2] << 16) | + ((unsigned long)value[3] << 24); rtc_time_to_tm(secs, tm); @@ -284,7 +285,8 @@ static int pm8xxx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm) return rc; } - secs = value[0] | (value[1] << 8) | (value[2] << 16) | (value[3] << 24); + secs = value[0] | (value[1] << 8) | (value[2] << 16) | + ((unsigned long)value[3] << 24); rtc_time_to_tm(secs, &alarm->time); -- 2.20.1