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| author | Vaibhav Jain <vaibhav@linux.vnet.ibm.com> | 2017-05-19 22:18:55 +0530 |
|---|---|---|
| committer | Alexandre Belloni <alexandre.belloni@free-electrons.com> | 2017-05-31 13:04:54 +0200 |
| commit | da96aea0ed177105cb13ee83b328f6c61e061d3f (patch) | |
| tree | a0f140bd6f0d3c6853e2b2f4b7390521d5083eef /drivers/rtc/interface.c | |
| parent | 6dc1cf6f932bb0ea4d8f5e913a0a401ecacd2f03 (diff) | |
| download | linux-da96aea0ed177105cb13ee83b328f6c61e061d3f.tar.gz linux-da96aea0ed177105cb13ee83b328f6c61e061d3f.tar.bz2 linux-da96aea0ed177105cb13ee83b328f6c61e061d3f.zip | |
rtc: interface: Validate alarm-time before handling rollover
In function __rtc_read_alarm() its possible for an alarm time-stamp to
be invalid even after replacing missing components with current
time-stamp. The condition 'alarm->time.tm_year < 70' will trigger this
case and will cause the call to 'rtc_tm_to_time64(&alarm->time)'
return a negative value for variable t_alm.
While handling alarm rollover this negative t_alm (assumed to seconds
offset from '1970-01-01 00:00:00') is converted back to rtc_time via
rtc_time64_to_tm() which results in this error log with seemingly
garbage values:
"rtc rtc0: invalid alarm value: -2-1--1041528741
2005511117:71582844:32"
This error was generated when the rtc driver (rtc-opal in this case)
returned an alarm time-stamp of '00-00-00 00:00:00' to indicate that
the alarm is disabled. Though I have submitted a separate fix for the
rtc-opal driver, this issue may potentially impact other
existing/future rtc drivers.
To fix this issue the patch validates the alarm time-stamp just after
filling up the missing datetime components and if rtc_valid_tm() still
reports it to be invalid then bails out of the function without
handling the rollover.
Reported-by: Steve Best <sbest@redhat.com>
Signed-off-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Diffstat (limited to 'drivers/rtc/interface.c')
| -rw-r--r-- | drivers/rtc/interface.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c index fc0fa7577636..8cec9a02c0b8 100644 --- a/drivers/rtc/interface.c +++ b/drivers/rtc/interface.c @@ -227,6 +227,13 @@ int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) missing = year; } + /* Can't proceed if alarm is still invalid after replacing + * missing fields. + */ + err = rtc_valid_tm(&alarm->time); + if (err) + goto done; + /* with luck, no rollover is needed */ t_now = rtc_tm_to_time64(&now); t_alm = rtc_tm_to_time64(&alarm->time); @@ -278,9 +285,9 @@ int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) dev_warn(&rtc->dev, "alarm rollover not handled\n"); } -done: err = rtc_valid_tm(&alarm->time); +done: if (err) { dev_warn(&rtc->dev, "invalid alarm value: %d-%d-%d %d:%d:%d\n", alarm->time.tm_year + 1900, alarm->time.tm_mon + 1, |