65528 bits is more than any reasonable key until we start supporting
post-quantum cryptography.
This limit is chosen to allow bit-sizes to be stored in 16 bits, with
65535 left to indicate an invalid value. It's a whole number of bytes,
which facilitates some calculations, in particular allowing a key of
exactly PSA_CRYPTO_MAX_STORAGE_SIZE to be created but not one bit
more.
As a resource usage limit, this is arguably too large, but that's out
of scope of the current commit.
Test that key import, generation and derivation reject overly large
sizes.
Stored keys must contain lifetime information. The lifetime used to be
implied by the location of the key, back when applications supplied
the lifetime value when opening the key. Now that all keys' metadata
are stored in a central location, this location needs to store the
lifetime explicitly.
Pass information via a key attribute structure rather than as separate
parameters to psa_crypto_storage functions. This makes it easier to
maintain the code when the metadata of a key evolves.
This has negligible impact on code size (+4B with "gcc -Os" on x86_64).
This file isn't like the other .function files: it isn't concatenated
by a separate preprocessing script, but included via C preprocessing.
Rename this file to .h. This isn't a normal C header, because it
defines auxiliary functions. But the functions aren't big and we only
have one compilation unit per executable, so this is good enough for
what we're doing.
Replace all calls to mbedtls_psa_crypto_free in tests by PSA_DONE.
This is correct for most tests, because most tests close open keys. A
few tests now fail; these tests need to be reviewed and switched back
to mbedtls_psa_crypto_free if they genuinely expected to end with some
slots still in use.
Create a specific file for helper functions that are related to the
PSA API. The reason for a separate file is so that it can include
<psa/crypto.h>, without forcing this header inclusion into every test
suite. In this commit, psa_helpers.function doesn't need psa/crypto.h
yet, but this will be the case in a subsequent commit.
Move PSA_ASSERT to psa_helpers.function, since that's the sort of
things it's for.
Include "psa_helpers.function" from the PSA crypto tests.
In the ITS test, don't include "psa_helpers". The ITS tests are
meant to stand alone from the rest of the library.
In psa_import_key, change the order of parameters to pass
the pointer where the newly created handle will be stored last.
This is consistent with most other library functions that put inputs
before outputs.
Change the scope of key identifiers to be global, rather than
per lifetime. As a result, you now need to specify the lifetime of a
key only when creating it.
After calling psa_get_key_attributes(), call
psa_reset_key_attributes() if the key may have domain parameters,
because that's the way to free the domain parameter substructure in
the attribute structure. Keep not calling reset() in some places where
the key can only be a symmetric key which doesn't have domain
parameters.
Update persistent_key_load_key_from_storage to the new attribute-based
key creation interface. I tweaked the code a little to make it simpler
and more robust without changing the core logic.
This commit starts a migration to a new interface for key creation.
Today, the application allocates a handle, then fills its metadata,
and finally injects key material. The new interface fills metadata
into a temporary structure, and a handle is allocated at the same time
it gets filled with both metadata and key material.
This commit was obtained by moving the declaration of the old-style
functions to crypto_extra.h and renaming them with the to_handle
suffix, adding declarations for the new-style functions in crypto.h
under their new name, and running
perl -i -pe 's/\bpsa_(import|copy|generator_import|generate)_key\b/$&_to_handle/g' library/*.c tests/suites/*.function programs/psa/*.c
perl -i -pe 's/\bpsa_get_key_lifetime\b/$&_from_handle/g' library/*.c tests/suites/*.function programs/psa/*.c
Many functions that are specific to the old interface, and which will
not remain under the same name with the new interface, are still in
crypto.h for now.
All functional tests should still pass. The documentation may have
some broken links.
Since there is now a single storage backend, we don't need a backend
interface. Make the functions that were declared in
psa_crypto_storage_backend.h and are now both defined and used in
psa_crypto_storage.c static, except for psa_is_key_present_in_storage
which is used by the gray-box tests and is now declared in
psa_crypto_storage.h.
Remove the type and bits arguments to psa_allocate_key() and
psa_create_key(). They can be useful if the implementation wants to
know exactly how much space to allocate for the slot, but many
implementations (including ours) don't care, and it's possible to work
around their lack by deferring size-dependent actions to the time when
the key material is created. They are a burden to applications and
make the API more complex, and the benefits aren't worth it.
Change the API and adapt the implementation, the units test and the
sample code accordingly.
Add new initializers for key policies and use them in our docs, example
programs, tests, and library code. Prefer using the macro initializers
due to their straightforwardness.
Change the way some lines are wrapped to cut at a more logical place.
This commit mainly rewrites multi-line calls to TEST_EQUAL, and also a
few calls to PSA_ASSERT.
This commit is the result of the following command, followed by
reindenting (but not wrapping lines):
perl -00 -i -pe 's/^( *)TEST_ASSERT\(([^;=]*)(?: |\n *)==([^;=]*)\);$/${1}TEST_EQUAL($2,$3);/gm' tests/suites/test_suite_psa_*.function
This commit is the result of the following command, followed by
reindenting (but not wrapping lines):
perl -00 -i -pe 's/^( *)TEST_ASSERT\(([^;=]*)(?: |\n *)==\s*PSA_SUCCESS\s*\);$/${1}PSA_ASSERT($2 );/gm' tests/suites/test_suite_psa_*.function
Switch from the direct use of slot numbers to handles allocated by
psa_allocate_key.
The general principle for each function is:
* Change `psa_key_slot_t slot` to `psa_key_handle_t handle` or
`psa_key_id_t key_id` depending on whether it's used as a handle to
an open slot or as a persistent name for a key.
* Call psa_create_key() before using a slot, instead of calling
psa_set_key_lifetime to make a slot persistent.
Remove the unit test persistent_key_is_configurable which is no longer
relevant.
Allow use of persistent keys, including configuring them, importing and
exporting them, and destroying them.
When getting a slot using psa_get_key_slot, there are 3 scenarios that
can occur if the keys lifetime is persistent:
1. Key type is PSA_KEY_TYPE_NONE, no persistent storage entry:
- The key slot is treated as a standard empty key slot
2. Key type is PSA_KEY_TYPE_NONE, persistent storage entry exists:
- Attempt to load the key from persistent storage
3. Key type is not PSA_KEY_TYPE_NONE:
- As checking persistent storage on every use of the key could
be expensive, the persistent key is assumed to be saved in
persistent storage, the in-memory key is continued to be used.
