linux-kernel - Re: [PATCH 01/16] move copyout of timespec into do_cpu

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Tue, 13 Jun 2017 09:46:40 +0200 (CEST)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Al Viro <viro@...IV.linux.org.uk>
cc:     linux-kernel@...r.kernel.org
Subject: Re: [PATCH 01/16] move copyout of timespec into do_cpu_nanosleep()

On Tue, 13 Jun 2017, Thomas Gleixner wrote:
> On Wed, 7 Jun 2017, Al Viro wrote:
> > @@ -1242,12 +1243,14 @@ static int do_cpu_nanosleep(const clockid_t which_clock, int flags,
> >  
> >  		error = -ERESTART_RESTARTBLOCK;
> > +		/*
> > +		 * Report back to the user the time still remaining.
> > +		 */
> > +		rmtp = restart->nanosleep.rmtp;
> > +		if (rmtp) {
> > +			struct timespec ts;
> > +			ts = timespec64_to_timespec(it.it_value);
> > +			if (copy_to_user(rmtp, &ts, sizeof(*rmtp)))
> > +				return -EFAULT;
> > +		}
> > +		restart->nanosleep.expires = timespec64_to_ns(rqtp);
> 
> Hmm, this looks wrong. But that was wrong before this patch already.
> 
> The restart code needs the absolute expiry time of the timer, but in case
> of flags != ABSTIME rqtp contains the relative expiry time.
> 
> So that want's to be fixed first. Need to figure out what's the least ugly
> way to do that. I'll have a look tomorrow.

Misread the code. rqtp is updated with the absolute expiry time when a
signal hits. Though with your changes we can simplify that further and
avoid the whole back and forth timespec conversion.

Thanks,

	tglx