Comment 0 for bug 1832625

Description: pkey: Indicate old mkvp only if old and curr. mkvp are different

Symptom: zkey validate shows wrong information about master key registers

Problem: When the CCA master key is set twice with the same master key,
               then the old and the current master key are the same and thus
               the verification patterns are the same, too. The check to report
               if a secure key is currently wrapped by the old master key
               erroneously reports old mkvp in this case.

Solution: Fix this by checking current and old mkvp and report OLD only if
               current and old mkvp are different.

Reproduction: Change the CCA master key but set the exact same master key that is already used. Then do a 'zkey validate' command on a secure key

Component: kernel 5.1 rc1
Upstream-ID: ebb7c695d3bc7a4986b92edc8d9ef43491be183e

This fix will be provided with kernel >=5.1 , will be integrate in 19.10 by default.
But should also be applied to 18.04 and 19.04