linux-kernel - Re: [PATCH v6] tpm: fix a race condition in tpm2_unseal

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Message-ID: <20160830184141.GA7031@intel.com>
Date:   Tue, 30 Aug 2016 21:41:41 +0300
From:   Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To:     Jason Gunthorpe <jgunthorpe@...idianresearch.com>
Cc:     Peter Huewe <peterhuewe@....de>, stable@...r.kernel.org,
        Marcel Selhorst <tpmdd@...horst.net>,
        "moderated list:TPM DEVICE DRIVER" 
        <tpmdd-devel@...ts.sourceforge.net>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v6] tpm: fix a race condition in tpm2_unseal_trusted()

On Tue, Aug 30, 2016 at 12:07:01PM -0600, Jason Gunthorpe wrote:
> On Tue, Aug 30, 2016 at 01:51:06AM +0300, Jarkko Sakkinen wrote:
> > Unseal and load operations should be done as an atomic operation. This
> > commit introduces unlocked tpm_transmit() so that tpm2_unseal_trusted()
> > can do the locking by itself.
> > 
> > v2: Introduced an unlocked unseal operation instead of changing locking
> >     strategy in order to make less intrusive bug fix and thus more
> >     backportable.
> > 
> > v3: Have also separate __tpm_transmit() that takes 'flags' in order to
> >     better localize the bug fix and make it easier to backport.
> > 
> > v4: Cleaned up the control flow in tpm2_unseal_trusted. Added the
> >     missing 'Fixes' line.
> > 
> > v5: Previous versions did not set the enum to any value, so it was set
> >     to zero. Changed enum to TPM_TRANSMIT_UNLOCKED because it is
> >     guaranteed to catch such situation. With change the common case
> >     adds so little clutter that the wrappers do not make sense anymore.
> > 
> > v6: Added flags parameter to internal TPM command wrappers to have
> >     an expected default behavior and documented them.
> 
> Yeah, this is nice.
> 
> BTW, do not put the vX: stuff into the commit message, and it would be
> best to include it after the diffstat the patch email

I was going to strip it but including it after the diffstat sounds like
a great idea.

> Reviewed-by: Jason Gunthorpe <jgunthorpe@...idianresearch.com>
> 
> Jason

/Jarkko