Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752656AbcJCWu5 (ORCPT ); Mon, 3 Oct 2016 18:50:57 -0400 Received: from mail-wm0-f67.google.com ([74.125.82.67]:33395 "EHLO mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751590AbcJCWuv (ORCPT ); Mon, 3 Oct 2016 18:50:51 -0400 From: Gabriele Mazzotta To: alexandre.belloni@free-electrons.com, a.zummo@towertech.it Cc: rtc-linux@googlegroups.com, linux-kernel@vger.kernel.org, Gabriele Mazzotta Subject: [PATCH v3] rtc-cmos: Reject unsupported alarm values Date: Tue, 4 Oct 2016 00:50:28 +0200 Message-Id: <20161003225028.3529-1-gabriele.mzt@gmail.com> X-Mailer: git-send-email 2.9.3 In-Reply-To: <20160902195516.7068-1-gabriele.mzt@gmail.com> References: <20160902195516.7068-1-gabriele.mzt@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2906 Lines: 108 Some platforms allows to specify the month and day of the month in which an alarm should go off, some others the day of the month and some others just the time. Currently any given value is accepted by the driver and only the supported fields are used to program the hardware. As consequence, alarms are potentially programmed to go off in the wrong moment. Fix this by rejecting any unsupported value. Signed-off-by: Gabriele Mazzotta --- drivers/rtc/rtc-cmos.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 72 insertions(+) diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c index 9bb14eb..2655432 100644 --- a/drivers/rtc/rtc-cmos.c +++ b/drivers/rtc/rtc-cmos.c @@ -328,14 +328,86 @@ static void cmos_irq_disable(struct cmos_rtc *cmos, unsigned char mask) cmos_checkintr(cmos, rtc_control); } +static int cmos_validate_alarm(struct device *dev, struct rtc_wkalrm *t) +{ + struct cmos_rtc *cmos = dev_get_drvdata(dev); + struct rtc_time now; + + cmos_read_time(dev, &now); + + if (!cmos->day_alrm) { + time64_t t_max_date; + time64_t t_alrm; + + t_max_date = rtc_tm_to_time64(&now); + t_max_date += 24 * 60 * 60 - 1; + t_alrm = rtc_tm_to_time64(&t->time); + if (t_alrm > t_max_date) { + dev_err(dev, + "Alarms can be up to one day in the future\n"); + return -EINVAL; + } + } else if (!cmos->mon_alrm) { + struct rtc_time max_date = now; + time64_t t_max_date; + time64_t t_alrm; + int max_mday; + + if (max_date.tm_mon == 11) { + max_date.tm_mon = 0; + max_date.tm_year += 1; + } else { + max_date.tm_mon += 1; + } + max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year); + if (max_date.tm_mday > max_mday) + max_date.tm_mday = max_mday; + + t_max_date = rtc_tm_to_time64(&max_date); + t_max_date -= 1; + t_alrm = rtc_tm_to_time64(&t->time); + if (t_alrm > t_max_date) { + dev_err(dev, + "Alarms can be up to one month in the future\n"); + return -EINVAL; + } + } else { + struct rtc_time max_date = now; + time64_t t_max_date; + time64_t t_alrm; + int max_mday; + + max_date.tm_year += 1; + max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year); + if (max_date.tm_mday > max_mday) + max_date.tm_mday = max_mday; + + t_max_date = rtc_tm_to_time64(&max_date); + t_max_date -= 1; + t_alrm = rtc_tm_to_time64(&t->time); + if (t_alrm > t_max_date) { + dev_err(dev, + "Alarms can be up to one year in the future\n"); + return -EINVAL; + } + } + + return 0; +} + static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t) { struct cmos_rtc *cmos = dev_get_drvdata(dev); unsigned char mon, mday, hrs, min, sec, rtc_control; + int ret; if (!is_valid_irq(cmos->irq)) return -EIO; + ret = cmos_validate_alarm(dev, t); + if (ret < 0) + return ret; + mon = t->time.tm_mon + 1; mday = t->time.tm_mday; hrs = t->time.tm_hour; -- 2.9.3