Messages in this thread | | | Subject | Re: [PATCH] time: verify time values in adjtimex ADJ_SETOFFSET to avoid overflow | From | Sasha Levin <> | Date | Sat, 5 Dec 2015 19:15:41 -0500 |
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On 12/05/2015 12:10 PM, Thomas Gleixner wrote: > On Thu, 3 Dec 2015, Sasha Levin wrote: > >> Make sure the tv_usec makes sense. We might multiply them later which can >> cause an overflow and undefined behavior. >> >> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> >> --- >> kernel/time/timekeeping.c | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c >> index d563c19..aa3c1c2 100644 >> --- a/kernel/time/timekeeping.c >> +++ b/kernel/time/timekeeping.c >> @@ -1987,6 +1987,10 @@ int do_adjtimex(struct timex *txc) >> >> if (txc->modes & ADJ_SETOFFSET) { >> struct timespec delta; >> + >> + if (txc->time.tv_usec >= USEC_PER_SEC || txc->time.tv_usec <= -USEC_PER_SEC) >> + return -EINVAL; > > That's not a canonical timeval. timeval_valid() is what you want to > check it. Or has adjtimex some magic exception here?
Nope, it looks like timeval_valid() is indeed what I've needed to use.
Is there a reason ntp_validate_timex() doesn't do timeval_valid() too for at least the ADJ_SETOFFSET case? If not, I'll add it in.
Thanks, Sasha
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