Re: [PATCH v4 2/2] selftests: tpm2: Reset the dictionary attack lock

From: Jarkko Sakkinen <jarkko@kernel.org>
To: Stefan Berger <stefanb@linux.ibm.com>
Cc: Stefan Berger <stefanb@linux.vnet.ibm.com>,
	linux-integrity@vger.kernel.org, peterhuewe@gmx.de,
	linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
	skhan@linuxfoundation.org
Subject: Re: [PATCH v4 2/2] selftests: tpm2: Reset the dictionary attack lock
Date: Wed, 1 Dec 2021 12:19:09 +0200	[thread overview]
Message-ID: <YadMHU0scgKvCTMV@iki.fi> (raw)
In-Reply-To: <YadLaHB0oJZYTMbh@iki.fi>

On Wed, Dec 01, 2021 at 12:16:11PM +0200, Jarkko Sakkinen wrote:
> On Mon, Nov 29, 2021 at 07:26:12PM -0500, Stefan Berger wrote:
> > 
> > On 11/29/21 18:43, Jarkko Sakkinen wrote:
> > > On Sat, Nov 27, 2021 at 11:10:52PM -0500, Stefan Berger wrote:
> > > > From: Stefan Berger <stefanb@linux.ibm.com>
> > > > 
> > > > Reset the dictionary attack lock to avoid the following types of test
> > > > failures after running the test 2 times:
> > > > 
> > > > ======================================================================
> > > > ERROR: test_unseal_with_wrong_policy (tpm2_tests.SmokeTest)
> > > > ----------------------------------------------------------------------
> > > > Traceback (most recent call last):
> > > >    File "/root/linux-ima-namespaces/tools/testing/selftests/tpm2/tpm2_tests.py", line 105, in test_unseal_with_wrong_policy
> > > >      blob = self.client.seal(self.root_key, data, auth, policy_dig)
> > > >    File "/root/linux-ima-namespaces/tools/testing/selftests/tpm2/tpm2.py", line 620, in seal
> > > >      rsp = self.send_cmd(cmd)
> > > >    File "/root/linux-ima-namespaces/tools/testing/selftests/tpm2/tpm2.py", line 397, in send_cmd
> > > >      raise ProtocolError(cc, rc)
> > > > tpm2.ProtocolError: TPM_RC_LOCKOUT: cc=0x00000153, rc=0x00000921
> > > > 
> > > > Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
> > > > ---
> > > >   tools/testing/selftests/tpm2/tpm2_tests.py | 2 ++
> > > >   1 file changed, 2 insertions(+)
> > > > 
> > > > diff --git a/tools/testing/selftests/tpm2/tpm2_tests.py b/tools/testing/selftests/tpm2/tpm2_tests.py
> > > > index e63a37819978..ad6f54c01adf 100644
> > > > --- a/tools/testing/selftests/tpm2/tpm2_tests.py
> > > > +++ b/tools/testing/selftests/tpm2/tpm2_tests.py
> > > > @@ -139,6 +139,8 @@ class SmokeTest(unittest.TestCase):
> > > >           except:
> > > >               self.client.flush_context(handle)
> > > >               raise
> > > > +        finally:
> > > > +            self.client.reset_da_lock()
> > > >           self.assertEqual(rc, tpm2.TPM2_RC_POLICY_FAIL)
> > > > -- 
> > > > 2.31.1
> > > > 
> > > I don't agree with this as a DA lock has legit use. This would be adequate
> > > for systems dedicated for kernel testing only.
> > 
> > The problem is this particular test case I am patching here causes the above
> > test failures upon rerun. We are testing the driver here presumably and not
> > the TPM2, so I think we should leave the TPM2 as cleaned up as possible,
> > thus my suggestion is to reset the DA lock and we won't hear any complaints
> > after that.
> 
> Ok.
> 
> > > We could make this available in the folder where TPM2 tests are:
> > > 
> > > https://git.kernel.org/pub/scm/linux/kernel/git/jarkko/tpm2-scripts.git/tree/tpm2-reset-da-lock
> > 
> > 
> > The tss packages also have command line tools to reset the DA lock, but it
> > shouldn't be necessary to use them after running a **driver** test case.
> 
> If you speak about TSS, please alway say which one :-)
> 
> Adding non-volatile state changes explicitly is to a test case is both

A typo, should be:

"Adding non-volatile state changes explicitly to a test case is both"

/Jarkko