From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jarkko Sakkinen Subject: Re: [PATCH v4 3/8] tpm: validate event log access before tpm_bios_log_setup Date: Mon, 3 Oct 2016 15:35:23 +0300 Message-ID: <20161003123523.GC9990@intel.com> References: <1475051682-23060-1-git-send-email-nayna@linux.vnet.ibm.com> <1475051682-23060-4-git-send-email-nayna@linux.vnet.ibm.com> <20161001120125.GC8664@intel.com> <20161001165436.GB13462@obsidianresearch.com> <20161001193239.GA3862@intel.com> <20161002212551.GB25872@obsidianresearch.com> <20161003122013.GA9990@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20161003122013.GA9990-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: tpmdd-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org To: Jason Gunthorpe Cc: tpmdd-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: tpmdd-devel@lists.sourceforge.net On Mon, Oct 03, 2016 at 03:20:13PM +0300, Jarkko Sakkinen wrote: > On Sun, Oct 02, 2016 at 03:25:51PM -0600, Jason Gunthorpe wrote: > > On Sat, Oct 01, 2016 at 10:32:39PM +0300, Jarkko Sakkinen wrote: > > > > chip held for the duration of any fops. Can open() start after the > > > > kref is dropped, etc. > > > > > > Why not make tpm_securityfs_data refcounted in order to remove > > > binding to the chip? > > > > The chip is already kref'd. How does swapping one kref for another > > solve anything? > > > > The possible issue is that the krefs are not covering > > the right code. > > > > The scheme you suggested is also way off the mark for how fops works, > > fops->close has no relation to the needed duration for 'data', the > > duration is related to securityfs_remove. > > Right, the above would not work because it's not linked to > securityfs_remove by any means. > > Are you trying to say that after securityfs_remove() there might be a > "grace period" when user space could still see the files visible and > open them? You have to provide something factors more concrete. Otherwise, I'm inclined to accept the approach in Naynas patch. It's an improvement. /Jarkko ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot