commit 4bddf4587c upstream.
After reading all the feedback, right now disabling the TPM2_TCG_HMAC
is the right call.
Other views discussed:
A. Having a kernel command-line parameter or refining the feature
otherwise. This goes to the area of improvements. E.g., one
example is my own idea where the null key specific code would be
replaced with a persistent handle parameter (which can be
*unambigously* defined as part of attestation process when
done correctly).
B. Removing the code. I don't buy this because that is same as saying
that HMAC encryption cannot work at all (if really nitpicking) in
any form. Also I disagree on the view that the feature could not
be refined to something more reasoable.
Also, both A and B are worst options in terms of backporting.
Thuss, this is the best possible choice.
Cc: stable@vger.kernel.or # v6.10+
Fixes: d2add27cf2 ("tpm: Add NULL primary creation")
Suggested-by: Chris Fenner <cfenn@google.com>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1bbf47539b