diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2011-09-07 13:03:48 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-09-07 13:03:48 -0700 |
| commit | 79016f648872549392d232cd648bd02298c2d2bb (patch) | |
| tree | 8b3f435b7ff3633b0a82313a1bb12d052f36c6b7 /kernel | |
| parent | e81b693c0104d6a767f998ee5a2e00b5acbbcd18 (diff) | |
| parent | 486257130873a2172d8eac2c182f7e578465bdd0 (diff) | |
Merge branch 'timers-fixes-for-linus' of git://tesla.tglx.de/git/linux-2.6-tip
* 'timers-fixes-for-linus' of git://tesla.tglx.de/git/linux-2.6-tip:
rtc: twl: Fix registration vs. init order
rtc: Initialized rtc_time->tm_isdst
rtc: Fix RTC PIE frequency limit
rtc: rtc-twl: Remove lockdep related local_irq_enable()
rtc: rtc-twl: Switch to using threaded irq
rtc: ep93xx: Fix 'rtc' may be used uninitialized warning
alarmtimers: Avoid possible denial of service with high freq periodic timers
alarmtimers: Memset itimerspec passed into alarm_timer_get
alarmtimers: Avoid possible null pointer traversal
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/time/alarmtimer.c | 18 |
1 files changed, 13 insertions, 5 deletions
diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c index 59f369f98a04..ea5e1a928d5b 100644 --- a/kernel/time/alarmtimer.c +++ b/kernel/time/alarmtimer.c @@ -441,6 +441,8 @@ static int alarm_timer_create(struct k_itimer *new_timer) static void alarm_timer_get(struct k_itimer *timr, struct itimerspec *cur_setting) { + memset(cur_setting, 0, sizeof(struct itimerspec)); + cur_setting->it_interval = ktime_to_timespec(timr->it.alarmtimer.period); cur_setting->it_value = @@ -479,11 +481,17 @@ static int alarm_timer_set(struct k_itimer *timr, int flags, if (!rtcdev) return -ENOTSUPP; - /* Save old values */ - old_setting->it_interval = - ktime_to_timespec(timr->it.alarmtimer.period); - old_setting->it_value = - ktime_to_timespec(timr->it.alarmtimer.node.expires); + /* + * XXX HACK! Currently we can DOS a system if the interval + * period on alarmtimers is too small. Cap the interval here + * to 100us and solve this properly in a future patch! -jstultz + */ + if ((new_setting->it_interval.tv_sec == 0) && + (new_setting->it_interval.tv_nsec < 100000)) + new_setting->it_interval.tv_nsec = 100000; + + if (old_setting) + alarm_timer_get(timr, old_setting); /* If the timer was already set, cancel it */ alarm_cancel(&timr->it.alarmtimer); |