Re: [PATCH] KEYS: trusted: defer execution of TPM-specific code until key instantiate

[Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>]

On Fri, Mar 22, 2019 at 07:01:39PM +0100, Roberto Sassu wrote:
> Commit 240730437deb ("KEYS: trusted: explicitly use tpm_chip structure from
> tpm_default_chip()") changed the tpm_chip argument of every TPM function
> from NULL to a pointer that is retrieved at module initialization time.
> 
> Unlike before this patch, the trusted module cannot be loaded if no TPM is
> available. Unfortunately, this causes a dependency problem because the
> encrypted key type requires the 'key_type_trusted' symbol when
> CONFIG_TRUSTED_KEYS is defined.
> 
> This patch fixes the issue by deferring the execution of TPM-specific code
> until a new trusted key is instantiated: init_tpm(), to obtain a tpm_chip
> pointer; init_digests(), introduced by commit 0b6cf6b97b7e ("tpm: pass an
> array of tpm_extend_digest structures to tpm_pcr_extend()"), to get random
> bytes from the TPM to lock a PCR.
> 
> Cc: stable@vger.kernel.org
> Fixes: 240730437deb ("KEYS: trusted: explicitly use tpm_chip structure from tpm_default_chip()")
> Reported-by: Dan Williams <dan.j.williams@intel.com>
> Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>

Definitive NAK for the release. Sorting out the dependency problem is
definitely out of scope for v5.1.

/Jarkko