doSoftwareKeyGen's symmetric branch (AES/HMAC/3DES) previously did
two things wrong:
1. It accepted attestationKey != null silently and then ignored the
reference: the symmetric path never consults attestationKey, so a
caller asking for BYO on a symmetric key would have received a key
with no certificate chain and no signal that BYO was dropped.
Reject early with KEYMINT_INVALID_ARGUMENT matching real KeyMint
HAL behavior.
2. The unsupported-algorithm path (e.g. 3DES, which has no JCA
mapping in this branch) threw SECURE_HW_COMMUNICATION_FAILED
(-49), the same numeric code InterceptorUtils labels as
Error::Km(UNSUPPORTED_TAG). That confuses diagnosis since -49 is
exactly the symptom the BYO fix series was just chasing. Use
KEYMINT_INVALID_ARGUMENT (-38) which is what real KeyMint returns
for unsupported algorithms in this context.
Surfaced by adversarial audit of 66a8c7f's broadened forceGenerate
gate, which now routes any attestationKey != null to software
unconditionally.
Enginex0
684542f4b1