[PATCH] rtc: wilco-ec: Sanitize values received from RTC

[Nick Crews]

Check that the time received from the RTC HW is valid,
otherwise the computation of rtc_year_days() in the next
line could, and sometimes does, crash the kernel.

While we're at it, fix the license to plain "GPL".

Signed-off-by: Nick Crews <ncr...@chromium.org>
---
 drivers/rtc/rtc-wilco-ec.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/rtc/rtc-wilco-ec.c b/drivers/rtc/rtc-wilco-ec.c
index 8ad4c4e6d557..0ccbf2dce832 100644
--- a/drivers/rtc/rtc-wilco-ec.c
+++ b/drivers/rtc/rtc-wilco-ec.c
@@ -110,8 +110,16 @@ static int wilco_ec_rtc_read(struct device *dev, struct 
rtc_time *tm)
        tm->tm_mday     = rtc.day;
        tm->tm_mon      = rtc.month - 1;
        tm->tm_year     = rtc.year + (rtc.century * 100) - 1900;
-       tm->tm_yday     = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
 
+       if (rtc_valid_tm(tm)) {
+               dev_warn(dev,
+                        "Time computed from EC RTC is invalid: sec=%d, min=%d, 
hour=%d, mday=%d, mon=%d, year=%d",
+                        tm->tm_sec, tm->tm_min, tm->tm_hour, tm->mday,
+                        tm->mon, tm->year);
+               return -EIO;
+       }
+
+       tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
        /* Don't compute day of week, we don't need it. */
        tm->tm_wday = -1;
 
@@ -188,5 +196,5 @@ module_platform_driver(wilco_ec_rtc_driver);
 
 MODULE_ALIAS("platform:rtc-wilco-ec");
 MODULE_AUTHOR("Nick Crews <ncr...@chromium.org>");
-MODULE_LICENSE("GPL v2");
+MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("Wilco EC RTC driver");
-- 
2.11.0