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 D30E7C169C4 for ; Wed, 6 Feb 2019 09:51:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AFA0120B1F for ; Wed, 6 Feb 2019 09:51:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727710AbfBFJu6 (ORCPT ); Wed, 6 Feb 2019 04:50:58 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:48415 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727103AbfBFJu6 (ORCPT ); Wed, 6 Feb 2019 04:50:58 -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 1grJr4-0008BE-1z; Wed, 06 Feb 2019 09:50:54 +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: 88pm860x: fix unintended sign extension Date: Wed, 6 Feb 2019 09:50:53 +0000 Message-Id: <20190206095053.12894-1-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#144925-144928 ("Unintended sign extension") Fixes: 008b30408c40 ("mfd: Add rtc support to 88pm860x") Signed-off-by: Colin Ian King --- drivers/rtc/rtc-88pm860x.c | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-) diff --git a/drivers/rtc/rtc-88pm860x.c b/drivers/rtc/rtc-88pm860x.c index 01ffc0ef8033..d25282b4a7dd 100644 --- a/drivers/rtc/rtc-88pm860x.c +++ b/drivers/rtc/rtc-88pm860x.c @@ -115,11 +115,13 @@ static int pm860x_rtc_read_time(struct device *dev, struct rtc_time *tm) pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf); dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1], buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]); - base = (buf[1] << 24) | (buf[3] << 16) | (buf[5] << 8) | buf[7]; + base = ((unsigned long)buf[1] << 24) | (buf[3] << 16) | + (buf[5] << 8) | buf[7]; /* load 32-bit read-only counter */ pm860x_bulk_read(info->i2c, PM8607_RTC_COUNTER1, 4, buf); - data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0]; + data = ((unsigned long)buf[3] << 24) | (buf[2] << 16) | + (buf[1] << 8) | buf[0]; ticks = base + data; dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n", base, data, ticks); @@ -145,7 +147,8 @@ static int pm860x_rtc_set_time(struct device *dev, struct rtc_time *tm) /* load 32-bit read-only counter */ pm860x_bulk_read(info->i2c, PM8607_RTC_COUNTER1, 4, buf); - data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0]; + data = ((unsigned long)buf[3] << 24) | (buf[2] << 16) | + (buf[1] << 8) | buf[0]; base = ticks - data; dev_dbg(info->dev, "set base:0x%lx, RO count:0x%lx, ticks:0x%lx\n", base, data, ticks); @@ -170,10 +173,12 @@ static int pm860x_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf); dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1], buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]); - base = (buf[1] << 24) | (buf[3] << 16) | (buf[5] << 8) | buf[7]; + base = ((unsigned long)buf[1] << 24) | (buf[3] << 16) | + (buf[5] << 8) | buf[7]; pm860x_bulk_read(info->i2c, PM8607_RTC_EXPIRE1, 4, buf); - data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0]; + data = ((unsigned long)buf[3] << 24) | (buf[2] << 16) | + (buf[1] << 8) | buf[0]; ticks = base + data; dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n", base, data, ticks); @@ -198,11 +203,13 @@ static int pm860x_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf); dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1], buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]); - base = (buf[1] << 24) | (buf[3] << 16) | (buf[5] << 8) | buf[7]; + base = ((unsigned long)buf[1] << 24) | (buf[3] << 16) | + (buf[5] << 8) | buf[7]; /* load 32-bit read-only counter */ pm860x_bulk_read(info->i2c, PM8607_RTC_COUNTER1, 4, buf); - data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0]; + data = ((unsigned long)buf[3] << 24) | (buf[2] << 16) | + (buf[1] << 8) | buf[0]; ticks = base + data; dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n", base, data, ticks); -- 2.20.1