From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Machek Subject: Re: [PATCH] procfs: make /proc style symlinks behave like "normal" symlinks Date: Thu, 19 Nov 2009 22:39:35 +0100 Message-ID: <20091119213935.GA11212@elf.ucw.cz> References: <1258638251-20034-1-git-send-email-jlayton@redhat.com> <20091119132833.30bc93a4@barsoom.rdu.redhat.com> <20091119143555.7851953f@barsoom.rdu.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "Eric W. Biederman" , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org To: Jeff Layton Return-path: Content-Disposition: inline In-Reply-To: <20091119143555.7851953f@barsoom.rdu.redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org > > Adding all of the short comings to followlink that readlink has is a problem, > > especially as followlink does much better now. > > > > At a practical level I think your changes are much easier to exploit than > > Pavels contrived example. > > > > I really don't have any problems with your first patch to proc to add the > > missing revalidate. > > > > Thanks, that makes sense. The raciness was evident once you pointed it > out, so I think you're correct that we can't take this approach. > > Adding the missing revalidations is fine, but I don't believe that > helps to fix Pavel's issue. I'll go back and take a more careful look > at the suggestion that Miklos made and see whether it makes sense to > implement a new FS_* flag for this, and see what it'll take to fix > Pavel's issue. One posibility would be to make open(/proc/XX/fd/XX) behave like dup(). That should solve the NFS problems, too, no? Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html