Re: [Y2038] [PATCH 05/11] time/posix-timers:Convert to the 64bit methods for k_clock callback functions

From: Arnd Bergmann <arnd@arndb.de>
To: y2038@lists.linaro.org
Cc: "Xunlei Pang" <pang.xunlei@linaro.org>,
	peterz@infradead.org, heiko.carstens@de.ibm.com,
	paulus@samba.org, cl@linux.com,
	"Heena Sirwani" <heenasirwani@gmail.com>,
	linux-arch@vger.kernel.org, linux-s390@vger.kernel.org,
	rafael.j.wysocki@intel.com, "Andrew Hunter" <ahh@google.com>,
	"Frédéric Weisbecker" <fweisbec@gmail.com>,
	"Paul Turner" <pjt@google.com>,
	riel@redhat.com, "Richard Cochran" <richardcochran@gmail.com>,
	tj@kernel.org, "John Stultz" <john.stultz@linaro.org>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	rth@twiddle.net, "Baolin Wang" <baolin.wang@linaro.org>,
	gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org,
	netdev@vger.kernel.org, schwidefsky@de.ibm.com,
	linux390@de.ibm.com, linuxppc-dev@lists.ozlabs.org
Subject: Re: [Y2038] [PATCH 05/11] time/posix-timers:Convert to the 64bit methods for k_clock callback functions
Date: Tue, 21 Apr 2015 10:45:48 +0200	[thread overview]
Message-ID: <8072977.i0FsrGW3CD@wuerfel> (raw)
In-Reply-To: <CAMz4kuKF2sU4tMD7UtDobu2kVDMp7cfHNERSPQ9Yyzs80tOzYg@mail.gmail.com>

On Tuesday 21 April 2015 16:36:13 Baolin Wang wrote:
> On 21 April 2015 at 04:48, Thomas Gleixner <tglx@linutronix.de> wrote:
> 
> > On Mon, 20 Apr 2015, Baolin Wang wrote:
> > >  /* Set clock_realtime */
> > >  static int posix_clock_realtime_set(const clockid_t which_clock,
> > > -                                 const struct timespec *tp)
> > > +                                 const struct timespec64 *tp)
> > >  {
> > > -     return do_sys_settimeofday(tp, NULL);
> > > +     struct timespec ts = timespec64_to_timespec(*tp);
> > > +
> > > +     return do_sys_settimeofday(&ts, NULL);
> >
> > Sigh. No. We first provide a proper function for this, which takes a
> > timespec64, i.e. do_sys_settimeofday64() instead of having this
> > wrapper mess all over the place.
> >
> 
> Thanks for your comments,but if use do_sys_settimeofday64() here that
> will  introduce
> a security bug: do_sys_settimeofday contains a capability
> check that normally prevents non-root users from setting the time.
> 
> With your change, any user can set the system time.

He was asking for a new do_sys_settimeofday64 function to be added,
not using the low-level do_settimeofday64.

	Arnd