linux-kernel - RE: [PATCH] tpm: separate cmd_ready/go_idle from runtime

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Message-ID: <5B8DA87D05A7694D9FA63FD143655C1B9D9477DD@hasmsx108.ger.corp.intel.com>
Date:   Thu, 7 Jun 2018 11:03:50 +0000
From:   "Winkler, Tomas" <tomas.winkler@...el.com>
To:     Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
CC:     Jason Gunthorpe <jgg@...pe.ca>,
        "Usyskin, Alexander" <alexander.usyskin@...el.com>,
        "linux-integrity@...r.kernel.org" <linux-integrity@...r.kernel.org>,
        "linux-security-module@...r.kernel.org" 
        <linux-security-module@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH] tpm: separate cmd_ready/go_idle from runtime_pm



> -----Original Message-----
> From: Jarkko Sakkinen [mailto:jarkko.sakkinen@...ux.intel.com]
> Sent: Thursday, June 07, 2018 13:25
> To: Winkler, Tomas <tomas.winkler@...el.com>
> Cc: Jason Gunthorpe <jgg@...pe.ca>; Usyskin, Alexander
> <alexander.usyskin@...el.com>; linux-integrity@...r.kernel.org; linux-
> security-module@...r.kernel.org; linux-kernel@...r.kernel.org
> Subject: Re: [PATCH] tpm: separate cmd_ready/go_idle from runtime_pm
> 
> On Wed, Jun 06, 2018 at 11:01:42AM +0000, Winkler, Tomas wrote:
> > >
> > > On Wed, May 30, 2018 at 10:52:28AM +0000, Winkler, Tomas wrote:
> > > > >
> > > > > On Wed, May 23, 2018 at 01:48:17PM +0000, Winkler, Tomas wrote:
> > > > > >
> > > > > > > On Tue, May 22, 2018 at 09:27:46AM +0000, Winkler, Tomas
> wrote:
> > > > > > > > >
> > > > > > > > > On Wed, May 16, 2018 at 10:46:00PM +0300, Tomas Winkler
> > > wrote:
> > > > > > > > > > New wrappers are added tpm_cmd_ready() and
> > > > > > > > > > tpm_go_idle()
> > > > > > > wrappers
> > > > > > > > > > to streamline tpm_try_transmit code.
> > > TPM_TRANSMIT_UNLOCKED
> > > > > > > > > > flag
> > > > > > > is
> > > > > > > > > abused
> > > > > > > > > > to resolve tpm spaces recursive calls to tpm_transmit().
> > > > > > > > >
> > > > > > > > > This looks good and all but I don't think we want to
> > > > > > > > > abuse anything in the driver code, do we?
> > > > > > > >
> > > > > > > > It's not abuse just the flag UNLOCKED is not really named
> > > > > > > > correctly I think this has to be backported so wanted to
> > > > > > > > do less invasive
> > > > > change.
> > > > > > >
> > > > > > > It should be renamed anyway and possible merge conflicts are
> > > > > > > not hard to sort out in this change. Can you rename it as SPACE?
> > > > > >
> > > > > > Not sure, I believe UNLOCKED is still better name than SPACE,
> > > > > >I'm not  sure this is Do you also want to remove
> TPM_TRANSMIT_RAW?
> > > > > > clk_enable is handling its own anti recursion counter 'data-
> > > > > >clkrun_enabled'
> > > > > > but it should be all handled under one flag I guess.
> > > > > >
> > > > > > > Right, and even without rename this will probably cause
> > > > > > > merge conflicts at least in v4.4 an v4.9 since in-kernel RM
> > > > > > > landed in v4.12, so not much gain not do the rename :-)
> > > > > >
> > > > > > I belive we should do minimal change and the big cleanup after
> that.
> > > > > > Not sure, I believe UNLOCKED is still better name than SPACE
> > > > > > even it wasn't
> > > > > the original intention.
> > > > > > No the SPACE is the issue, but any recursion call into
> > > > > > tpm_transmit. A bigger change is needed and rename to SPACE
> > > > > > would be just another
> > > > > intermediat change.
> > > > > >
> > > > > > Please reconsider.
> > > > > >
> > > > > > Thanks
> > > > > > Tomas
> > > > >
> > > > > Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
> > > >
> > > >
> > > > Does it mean you're Okay with the patch now?
> > > > Thanks
> > > > Tomas
> > >
> > > The change looks good but I'll have to test it.
> > Any updates?
> > Thanks
> 
> Tested-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>

I've just realized we have issue in tpm_unseal_trusted() 
As TPM_TRANSMIT_UNLOCKED is used really just in 'locking' sense of the flow, it's not nested.
Any of testing flows doesn't covers it. It's used only from by security/keys/trusted.c only

Then I don't have a short fix for this issue. Will use TPM_TRANSMIT_RAW,
 maybe calling it TPM_TRANSMIT_NESTED.  

Thanks
Tomas


> 
> /Jarkko