linux-kernel - Re: [PATCH 6/6] tpm2: add session handle context saving and restoring to the space code

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Message-ID: <1486743431.2502.6.camel@HansenPartnership.com>
Date:   Fri, 10 Feb 2017 08:17:11 -0800
From:   James Bottomley <James.Bottomley@...senPartnership.com>
To:     Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>,
        tpmdd-devel@...ts.sourceforge.net
Cc:     linux-security-module@...r.kernel.org,
        Peter Huewe <peterhuewe@....de>,
        Marcel Selhorst <tpmdd@...horst.net>,
        Jason Gunthorpe <jgunthorpe@...idianresearch.com>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 6/6] tpm2: add session handle context saving and
 restoring to the space code

On Fri, 2017-02-10 at 14:32 +0200, Jarkko Sakkinen wrote:
> On Wed, Feb 08, 2017 at 01:07:08PM +0200, Jarkko Sakkinen wrote:
> > From: James Bottomley <James.Bottomley@...senPartnership.com>
[...] 
> > +static int tpm2_session_add(struct tpm_chip *chip, u32 handle)
> > +{
> > +	struct tpm_space *space = &chip->work_space;
> > +	int i;
> > +
> > +	for (i = 0; i < ARRAY_SIZE(space->session_tbl); i++)
> > +		if (space->session_tbl[i] == 0)
> > +			break;
> > +	if (i == ARRAY_SIZE(space->session_tbl)) {
> > +		dev_err(&chip->dev, "out of session slots\n");
> 
> This really should be dev_dbg.

This was my reply to the comment the last time:

    I can do that, but I think this should be higher than debug.  If
    this trips, something an application was doing will fail with a non
    TPM error and someone may wish to investigate why.  Having a kernel
    message would help with that (but they won't see it if it's debug).

    I'm also leaning towards the idea that we should actually have one
    more _tbl slot than we know the TPM does, so that if someone goes
    over it's the TPM that gives them a real TPM out of memory error
    rather than the space code returning -ENOMEM.

    If you agree, I think it should be four for both sessions_tbl and
    context_tbl.

So I really don't think it should be debug.  Could we compromise on
dev_info?

James