Re: [PATCH RFC 2/4] tpm: validate TPM 2.0 commands

[Jarkko Sakkinen <jarkko.sakkinen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>]

On Wed, Jan 04, 2017 at 02:22:45PM -0500, Stefan Berger wrote:
>    James Bottomley <jejb-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org> wrote on 01/04/2017 02:05:35 PM:
> 
>    > From: James Bottomley <jejb-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
>    > To: Stefan Berger/Watson/IBM@IBMUS
>    > Cc: Jarkko Sakkinen <jarkko.sakkinen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>, tpmdd-
>    > devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, Jason Gunthorpe
>    <jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
>    > Date: 01/04/2017 02:05 PM
>    > Subject: Re: [tpmdd-devel] [PATCH RFC 2/4] tpm: validate TPM 2.0
>    commands
>    >
>    > On Wed, 2017-01-04 at 13:59 -0500, Stefan Berger wrote:
>    > > [   67.699811] WARNING: CPU: 12 PID: 870 at mm/page_alloc.c:3511
>    >
>    > What's the code context around this line in your source?  Or what
>    > kernel version?  If it's this
>    >
>    >    if (order >= MAX_ORDER) {
>    >       WARN_ON_ONCE(!(gfp_mask & __GFP_NOWARN));
>    >       return NULL;
>    >    }
>    >
> 
>    I am running Jarkko's tree, the tabrm branch. 4.9.0-rc5 I think. I have
>    exactly what you are showing above.
>    > Then I think you may have returned bogus data to TPM_PT_TOTAL_COMMANDS;
>    > perhaps print nr_commands.
> 
>    Ha, what is likely the cause here is that the test suite, which implements
>    only a few commands to respond to the kernel with from the vtpm proxy
>    side, isn't feeding good data to the driver and the nr_commands ends up
>    being 0... or actually bogus data / not initialized. I guess the function
>    should check for valid input.

So, what kind of validation do you suggest? Checking it whether it is
zero?

/Jarkko

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