From: Jarkko Sakkinen <jarkko.sakkinen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
To: Jason Gunthorpe
<jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
Cc: linux-security-module-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
tpmdd-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org,
open list <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Subject: Re: [PATCH] tpm: fix byte order related arithmetic inconsistency in tpm_getcap()
Date: Wed, 24 May 2017 09:59:50 -0700 [thread overview]
Message-ID: <20170524165950.mdaqortjrdhtabke@intel.com> (raw)
In-Reply-To: <20170515153934.GB3433-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
On Mon, May 15, 2017 at 09:39:34AM -0600, Jason Gunthorpe wrote:
> On Mon, May 15, 2017 at 02:36:02PM +0300, Jarkko Sakkinen wrote:
> > On Wed, May 10, 2017 at 03:34:58PM +0300, Jarkko Sakkinen wrote:
> > > On Tue, May 09, 2017 at 09:13:08AM -0600, Jason Gunthorpe wrote:
> > > > On Tue, May 09, 2017 at 05:13:53PM +0300, Jarkko Sakkinen wrote:
> > > > > On Sun, May 07, 2017 at 08:50:02PM +0300, Jarkko Sakkinen wrote:
> > > > > > You should not do arithmetic with __be32 or __le32 types because
> > > > > > sometimes it results incorrect results. Calculations must be done only
> > > > > > with integers that are in in the CPU byte order. This commit migrates
> > > > > > tpm_getcap() to struct tpm_buf in order to sort out these issues.
> > > > > >
> > > > > > Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
> > > > > > Now this should work as Robertos patches move byte order conversion
> > > > > > where it should be. Sadly I'm out of reach to my Dell E6400 laptop
> > > > > > that I use for TPM 1.2 testing.
> > > > > > drivers/char/tpm/tpm-interface.c | 30 ++++++++++++++++--------------
> > > > > > drivers/char/tpm/tpm.h | 13 -------------
> > > > > > 2 files changed, 16 insertions(+), 27 deletions(-)
> > > > >
> > > > > I've now tested this with TPM 1.2. Any complains?
> > > >
> > > > Seems reasonable, but which linke had the problematic arithmetic?
> > > >
> > > > Jason
> > >
> > > Arithmetic should work but it's not a good practice to do additions,
> > > substractions or multiplications in any other byte order than the CPU
> > > byte order.
> > >
> > > sparse also complains about this.
> >
> > Can I get your Reviewed-by for this one?
>
> Sure, but I'm still wondering what the sparse warning was?
>
> Jason
This type of errors
drivers/char/tpm//tpm-interface.c:492:42: warning: bad assignment (-=) to restricted __be32
/Jarkko
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prev parent reply other threads:[~2017-05-24 16:59 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-07 17:50 [PATCH] tpm: fix byte order related arithmetic inconsistency in tpm_getcap() Jarkko Sakkinen
2017-05-09 14:13 ` Jarkko Sakkinen
2017-05-09 15:13 ` Jason Gunthorpe
2017-05-10 12:34 ` Jarkko Sakkinen
2017-05-10 23:41 ` Luc Van Oostenryck
2017-05-11 10:16 ` Jarkko Sakkinen
2017-05-15 11:36 ` [tpmdd-devel] " Jarkko Sakkinen
2017-05-15 15:39 ` Jason Gunthorpe
[not found] ` <20170515153934.GB3433-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-05-24 16:59 ` Jarkko Sakkinen [this message]
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