Messages in this thread | | | From | Dan Williams <> | Date | Thu, 21 Mar 2019 09:30:24 -0700 | Subject | Re: [PATCH] security/keys/trusted: Allow operation without hardware TPM |
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On Thu, Mar 21, 2019 at 7:27 AM Roberto Sassu <roberto.sassu@huawei.com> wrote: > > On 3/21/2019 2:54 PM, Jarkko Sakkinen wrote: > > On Mon, Mar 18, 2019 at 04:45:13PM -0700, Dan Williams wrote: > >> Rather than fail initialization of the trusted.ko module, arrange for > >> the module to load, but rely on trusted_instantiate() to fail > >> trusted-key operations. > >> > >> Fixes: 240730437deb ("KEYS: trusted: explicitly use tpm_chip structure...") > >> Cc: Roberto Sassu <roberto.sassu@huawei.com> > >> Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> > >> Cc: James Bottomley <jejb@linux.ibm.com> > >> Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> > >> Cc: Mimi Zohar <zohar@linux.ibm.com> > >> Cc: David Howells <dhowells@redhat.com> > >> Signed-off-by: Dan Williams <dan.j.williams@intel.com> > > > > It should check for chip in each function that uses TPM now that > > the code does not rely on default chip. Otherwise, the semantics > > are kind of inconsistent. > > If no other TPM function can be used before a successful key > instantiate, checking for a chip only in trusted_instantiate() seems > sufficient. Then, the same chip will be used by all TPM functions until > module unloading, since we incremented the reference count. > > I would suggest to move the tpm_default_chip() and init_digests() calls > to trusted_instantiate() to restore the old behavior of init_trusted(). > > trusted_instantiate() should look like: > --- > if (!chip) { > chip = tpm_default_chip(); > if (!chip) > return -ENODEV; > } > > if (!digests) { > ret = init_digests(); > if (ret < 0) > return ret; > }
This patch already achieves that because tpm_find_get_ops() will fail and cause tpm_is_tpm2() to return NULL.
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