The methods to import and generate a key in a secure element drivers
were written for an earlier version of the application-side interface.
Now that there is a psa_key_attributes_t structure that combines all
key metadata including its lifetime (location), type, size, policy and
extra type-specific data (domain parameters), pass that to drivers
instead of separate arguments for each piece of metadata. This makes
the interface less cluttered.
Update parameter names and descriptions to follow general conventions.
Document the public-key output on key generation more precisely.
Explain that it is optional in a driver, and when a driver would
implement it. Declare that it is optional in the core, too (which
means that a crypto core might not support drivers for secure elements
that do need this feature).
Update the implementation and the tests accordingly.
Register an existing key in a secure element.
Minimal implementation that doesn't call any driver method and just
lets the application declare whatever it wants.
Pass the key creation method (import/generate/derive/copy) to the
driver methods to allocate or validate a slot number. This allows
drivers to enforce policies such as "this key slot can only be used
for keys generated inside the secure element".
Allow the application to choose the slot number in a secure element,
rather than always letting the driver choose.
With this commit, any application may request any slot. In an
implementation with isolation, it's up to the service to filter key
creation requests and apply policies to limit which applications can
request which slot.
Test the behavior of the getter/setter functions.
Test that psa_get_key_slot_number() reports a slot number for a key in
a secure element, and doesn't report a slot number for a key that is
not in a secure element.
Test that psa_get_key_slot_number() reports the correct slot number
for a key in a secure element.
Add a parameter to the key import method of a secure element driver to
make it report the key size in bits. This is necessary (otherwise the
core has no idea what the bit-size is), and making import report it is
easier than adding a separate method (for other key creation methods,
this information is an input, not an output).
Run all functions that take a key handle as input with a key that is
in a secure element. All calls are expected to error out one way or
another (not permitted by policy, invalid key type, method not
implemented in the secure element, ...). The goal of this test is to
ensure that nothing bad happens (e.g. invalid pointer dereference).
Run with various key types and algorithms to get good coverage.
Secure element support has its own source file, and in addition
requires many hooks in other files. This is a nontrivial amount of
code, so make it optional (but default on).
