cryptfs: Optionally get crypto type as a property
Instead of hardcoding to "aes-cbc-essiv:sha256" with a 16 byte
key, we introduce a new property, "ro.crypto.fde_algorithm",
to allow the use of different crypto types. The only other
method we currently support is "speck128-xts-plain64" with
a 32 byte key, although new crypto types are easily added.
We intentionally derive things like the crypto name and the
keysize from the given property name. This means the code
must be changed for each new crypto type we want to support,
but that's worth it to remove the exploit vector of crypto
types with incorrect key sizes.
Due to previous refactoring CLs, this has minimal impact on
the current code other than changing what we return for
cryptfs_get_{keysize,crypto_name}.
Bug: 73079191
Test: Flashed onto a gobo device with the property set for SPECK, and confirmed via kernel debug output we were using SPECK on the device.
Change-Id: I9c9df61590344c5f62114dfbf679031b0c2ceb1f
1 file changed