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SubjectRe: [PATCH] RTC: Ensure that time being passed to set_alarm() is valid.
On Wed, 7 Jun 2006 11:39:11 -0700
Andrew Morton <akpm@osdl.org> wrote:

> > diff -urN -x CVS linux-2.6.17-rc6/drivers/rtc/interface.c
> > linux-2.6.17-rc/drivers/rtc/interface.c
> > --- linux-2.6.17-rc6/drivers/rtc/interface.c Tue Jun 6 10:28:05 2006
> > +++ linux-2.6.17-rc/drivers/rtc/interface.c Wed Jun 7 11:46:28 2006
> > @@ -129,6 +129,10 @@
> > int err;
> > struct rtc_device *rtc = to_rtc_device(class_dev);
> >
> > + err = rtc_valid_tm(&alarm->time);
> > + if (err != 0)
> > + return err;
> > +
> > err = mutex_lock_interruptible(&rtc->ops_lock);
> > if (err)
> > return -EBUSY;
> >
>
> More details, please. How can this situation come about? Buggy kernel
> code? Userspace action?

both of them. this call is used by the dev interface
but might also be used by any in-kernel user (there are none
at the moment, but we might have them in the future).

the same kind of check is done in rtc_set_time()
for the same reason.

however, the dev interface (RTC_ALM_SET)
sets some of the tm fields to -1, which is
invalid for rtc_valid_tm.

I haven't thought of this when I suggested to Andrew Victor
to add this rtc_valid_tm call.

so we might have to remove this call or to modify
rtc_valid_tm to detect this.

suggestions?

--

Best regards,

Alessandro Zummo,
Tower Technologies - Turin, Italy

http://www.towertech.it

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