From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932288AbaLBLQr (ORCPT ); Tue, 2 Dec 2014 06:16:47 -0500 Received: from www.linutronix.de ([62.245.132.108]:47365 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751523AbaLBLQq (ORCPT ); Tue, 2 Dec 2014 06:16:46 -0500 Date: Tue, 2 Dec 2014 12:16:43 +0100 (CET) From: Thomas Gleixner To: Sasha Levin cc: linux-kernel@vger.kernel.org, John Stultz Subject: Re: [PATCH] time: settimeofday: validate the values of tv fomr user In-Reply-To: <1417493050-13594-5-git-send-email-sasha.levin@oracle.com> Message-ID: References: <1417493050-13594-1-git-send-email-sasha.levin@oracle.com> <1417493050-13594-5-git-send-email-sasha.levin@oracle.com> User-Agent: Alpine 2.11 (DEB 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 1 Dec 2014, Sasha Levin wrote: > An unvalidated user input is multiplied by a constant, which can result in > an undefined behaviour for large values. While this is validated later, > we should avoid triggering undefined behaviour. > > Signed-off-by: Sasha Levin > --- > kernel/time/time.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/kernel/time/time.c b/kernel/time/time.c > index 9ec4fa5..6f53df7 100644 > --- a/kernel/time/time.c > +++ b/kernel/time/time.c > @@ -200,6 +200,10 @@ SYSCALL_DEFINE2(settimeofday, struct timeval __user *, tv, > if (tv) { > if (copy_from_user(&user_tv, tv, sizeof(*tv))) > return -EFAULT; > + > + if (user_tv.tv_usec > USEC_PER_SEC || user_tv.tv_usec < 0) > + return -EINVAL; We should create timeval_valid() for this with the same logic as timespec_valid(). Thanks, tglx