linux-kernel - Re: [PATCH] parport/ppdev: fix registration of sysctl entries

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]

Message-ID: <20080706150608.GA5401@joi>
Date:	Sun, 6 Jul 2008 17:07:02 +0200
From:	Marcin Slusarz <marcin.slusarz@...il.com>
To:	Al Viro <viro@...IV.linux.org.uk>
Cc:	LKML <linux-kernel@...r.kernel.org>, Frans Pop <elendil@...net.nl>,
	"Eric W. Biederman" <ebiederm@...ssion.com>
Subject: Re: [PATCH] parport/ppdev: fix registration of sysctl entries

On Sun, Jul 06, 2008 at 01:11:48AM +0100, Al Viro wrote:
> On Sun, Jul 06, 2008 at 12:51:48AM +0100, Al Viro wrote:
> 
> > I don't believe that it's right.  Note that if you *do* race there, you
> > are fucked regardless of sysctls - ppdev.c::register_device() racing
> > with itself will do tons of fun things all by itself (starting with two
> > threads allocating different pdev and both setting pp->pdev).

I wouldn't call it a race - BKL is protecting multiple ioctl calls, so we
won't ever claim the device from two different threads.

> BTW, with your patch you'll have 100% reproducible double registration if
> you do PPCLAIM/PPRELEASE/PPCLAIN on one file descriptor.

Yes, I didn't notice PPRELEASE ioctl (I thought releasing the device is
done during close()).
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/