Eric Biggers 935b0c41ff ANDROID: block: require drivers to declare supported crypto key type(s) ...

We need a way to tell which type of keys the inline crypto hardware
supports (standard, wrapped, or both), so that fallbacks can be used
when needed (either blk-crypto-fallback, or fscrypt fs-layer crypto).

We can't simply assume that

    keyslot_mgmt_ll_ops::derive_raw_secret == NULL

means only standard keys are supported and that

    keyslot_mgmt_ll_ops::derive_raw_secret != NULL

means that only wrapped keys are supported, because device-mapper
devices always implement this method.  Also, hardware might support both
types of keys.

Therefore, add a field keyslot_manager::features which contains a
bitmask of flags which indicate the supported types of keys.  Drivers
will need to fill this in.  This patch makes the UFS standard crypto
code set BLK_CRYPTO_FEATURE_STANDARD_KEYS, but UFS variant drivers may
need to set BLK_CRYPTO_FEATURE_WRAPPED_KEYS instead.

Then, make keyslot_manager_crypto_mode_supported() take the key type
into account.

Bug: 137270441
Bug: 151100202
Test: 'atest vts_kernel_encryption_test' on Pixel 4 with the
      inline crypto patches backported, and also on Cuttlefish.
Change-Id: Ied846c2767c1fd2f438792dcfd3649157e68b005
Signed-off-by: Eric Biggers <ebiggers@google.com>

2020-04-04 16:32:16 +00:00

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