tree 92635d659c740d4e4b8288a73217e7a71db12325
parent 571c8a450702a23b2290796f46d38ac54a9e034c
author Rubin Xu <rubinxu@google.com> 1509464432 +0000
committer Rubin Xu <rubinxu@google.com> 1509754690 +0000

Swap the order of synthetic password wrapping

Synthetic password is double encrypted by both a random auth-bound keymaster
key and a secret derived from user password. In order to avoid a password
verification oracle without rate limiting, synthetic password needs to be
encrypted by the derived secret first, and then the auth-bound key. This
change corrects the order of encryptions, as well as adds an upgrade path to
refresh existing credentials.

Test: Running an old build with existing password, flash to new build,
      verify the device unlocks successfully.
Bug: 68694819

Change-Id: Ifdaa01f3f4ddd5bb3f3d808d38f440ced729034f
Merged-In: Ifdaa01f3f4ddd5bb3f3d808d38f440ced729034f