Commit-ID: 83a06bf50bdf2074b9404951ff60e142d159d93b Gitweb: http://git.kernel.org/tip/83a06bf50bdf2074b9404951ff60e142d159d93b Author: Marcelo Roberto Jimenez <mroberto@xxxxxxxxxxxxxxxxxxxxx> AuthorDate: Wed, 2 Feb 2011 16:04:02 -0200 Committer: John Stultz <john.stultz@xxxxxxxxxx> CommitDate: Thu, 3 Feb 2011 12:59:50 -0800 RTC: Prevents a division by zero in kernel code. This patch prevents a user space program from calling the RTC_IRQP_SET ioctl with a negative value of frequency. Also, if this call is make with a zero value of frequency, there would be a division by zero in the kernel code. [jstultz: Also initialize irq_freq to 1 to catch other divbyzero issues] CC: Alessandro Zummo <a.zummo@xxxxxxxxxxxx> CC: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Signed-off-by: Marcelo Roberto Jimenez <mroberto@xxxxxxxxxxxxxxxxxxxxx> Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx> --- drivers/rtc/class.c | 1 + drivers/rtc/interface.c | 3 +++ 2 files changed, 4 insertions(+), 0 deletions(-) diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c index 9583cbc..c404b61 100644 --- a/drivers/rtc/class.c +++ b/drivers/rtc/class.c @@ -143,6 +143,7 @@ struct rtc_device *rtc_device_register(const char *name, struct device *dev, rtc->id = id; rtc->ops = ops; rtc->owner = owner; + rtc->irq_freq = 1; rtc->max_user_freq = 64; rtc->dev.parent = dev; rtc->dev.class = rtc_class; diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c index 925006d..a0c0196 100644 --- a/drivers/rtc/interface.c +++ b/drivers/rtc/interface.c @@ -464,6 +464,9 @@ int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq) int err = 0; unsigned long flags; + if (freq <= 0) + return -EINVAL; + spin_lock_irqsave(&rtc->irq_task_lock, flags); if (rtc->irq_task != NULL && task == NULL) err = -EBUSY; -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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