From e411eea119543ac77e21122271b3888f7e003b3a Mon Sep 17 00:00:00 2001 From: Alexandre Belloni Date: Tue, 5 Jun 2018 23:09:14 +0200 Subject: [PATCH] rtc: ensure rtc_set_alarm fails when alarms are not supported [ Upstream commit abfdff44bc38e9e2ef7929f633fb8462632299d4 ] When using RTC_ALM_SET or RTC_WKALM_SET with rtc_wkalrm.enabled not set, rtc_timer_enqueue() is not called and rtc_set_alarm() may succeed but the subsequent RTC_AIE_ON ioctl will fail. RTC_ALM_READ would also fail in that case. Ensure rtc_set_alarm() fails when alarms are not supported to avoid letting programs think the alarms are working for a particular RTC when they are not. Signed-off-by: Alexandre Belloni Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/rtc/interface.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c index b7daa6bc2f8a..d225e5db37a7 100644 --- a/drivers/rtc/interface.c +++ b/drivers/rtc/interface.c @@ -381,6 +381,11 @@ int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) { int err; + if (!rtc->ops) + return -ENODEV; + else if (!rtc->ops->set_alarm) + return -EINVAL; + err = rtc_valid_tm(&alarm->time); if (err != 0) return err;