Renamed the tests because they are explicitly testing Curve25519 and
nothing else. Improved test coverage, test documentation and extended
in-code documentation with a specific reference to the standard as well.
crypto_extra.h has a dependency on platform_util.h for
MBEDTLS_DEPRECATED_NUMERIC_CONSTANT. Make the dependency explicit by
including platform_util.h. Although in most use cases the header should
already be included by something else, it doesn't hurt to include it
again and helps to clarify dependencies.
The library is able to perform computations and cryptographic schemes on
curves with x coordinate ladder representation. Here we add the
capability to export such points.
The function `mbedtls_mpi_write_binary()` writes big endian byte order,
but we need to be able to write little endian in some caseses. (For
example when handling keys corresponding to Montgomery curves.)
Used `echo xx | tac -rs ..` to transform the test data to little endian.
The private keys used in ECDH differ in the case of Weierstrass and
Montgomery curves. They have different constraints, the former is based
on big endian, the latter little endian byte order. The fundamental
approach is different too:
- Weierstrass keys have to be in the right interval, otherwise they are
rejected.
- Any byte array of the right size is a valid Montgomery key and it
needs to be masked before interpreting it as a number.
Historically it was sufficient to use mbedtls_mpi_read_binary() to read
private keys, but as a preparation to improve support for Montgomery
curves we add mbedtls_ecp_read_key() to enable uniform treatment of EC
keys.
For the masking the `mbedtls_mpi_set_bit()` function is used. This is
suboptimal but seems to provide the best trade-off at this time.
Alternatives considered:
- Making a copy of the input buffer (less efficient)
- removing the `const` constraint from the input buffer (breaks the api
and makes it less user friendly)
- applying the mask directly to the limbs (violates the api between the
modules and creates and unwanted dependency)
The library is able to perform computations and cryptographic schemes on
curves with x coordinate ladder representation. Here we add the
capability to import such points.
The function `mbedtls_mpi_read_binary()` expects big endian byte order,
but we need to be able to read from little endian in some caseses. (For
example when handling keys corresponding to Montgomery curves.)
Used `echo xx | tac -rs .. | tr [a-z] [A-Z]` to transform the test data
to little endian and `echo "ibase=16;xx" | bc` to convert to decimal.
Define MBEDTLS_ECDH_LEGACY_CONTEXT in config.h instead of hard-coding
this in ecdh.h so that its absence can be tested. Document it as
experimental so that we reserve the right to change it in the future.
Additional work done as part of merge:
- Run ./tests/scripts/check-generated-files.sh and check in the
resulting changes to programs/ssl/query_config.c
If mbedtls_ecdh_get_params is called with keys belonging to
different groups, make it return an error the second time, rather than
silently interpret the first key as being on the second curve.
This makes the non-regression test added by the previous commit pass.
Add a test case for doing an ECDH calculation by calling
mbedtls_ecdh_get_params on both keys, with keys belonging to
different groups. This should fail, but currently passes.
In places where we detect a context is in a bad state and there is no
sensitive data to clear, simply return PSA_ERROR_BAD_STATE and don't
abort on behalf of the application. The application will choose what to
do when it gets a bad state error.
The motivation for this change is that an application should decide what
to do when it misuses the API and encounters a PSA_ERROR_BAD_STATE
error. The library should not attempt to abort on behalf of the
application, as that may not be the correct thing to do in all
circumstances.
Calling psa_*_setup() twice on a MAC, cipher, or hash context should
result in a PSA_ERROR_BAD_STATE error because the operation has already
been set up.
Fixes#10
Extend hash bad order test in line with the new bad order tests for MAC
and cipher, covering more cases and making comments and test layout
consistent.
Ensure that when doing hash operations out of order, PSA_ERROR_BAD_STATE
is returned as documented in crypto.h and the PSA Crypto specification.
Switch to the terminology "key file identifier", as has been done in
the code.
The owner uid is now in the upper 32 bits of the key file identifier,
which facilitates namespacing.
When building for the PSA crypto service (defined(PSA_CRYPTO_SECURE)),
define psa_key_owner_id_t as int32_t, which is how a PSA platform
encodes partition identity. Note that this only takes effect when the
build option MBEDTLS_PSA_CRYPTO_KEY_FILE_ID_ENCODES_OWNER is active.
Support this configuration in the ITS backend.
Declare the owner as psa_key_owner_id_t, of which an implementation
must be provided separately.
Make this a configuration option
MBEDTLS_PSA_CRYPTO_KEY_FILE_ID_ENCODES_OWNER, to make the conditional
compilation flow easier to follow. Declare it in config.h to
pacify check_names.sh.
Support for a specific implementation of psa_key_owner_id_t in storage
backends will come in a subsequent commit.
Differentiate between _key identifiers_, which are always `uint32_t`,
and _key file identifiers_, which are platform-dependent. Normally,
the two are the same.
In `psa/crypto_platform.h`, define `psa_app_key_id_t` (which is always
32 bits, the standard key identifier type) and
`psa_key_file_id_t` (which will be different in some service builds).
A subsequent commit will introduce a platform where the two are different.
It would make sense for the function declarations in `psa/crypto.h` to
use `psa_key_file_id_t`. However this file is currently part of the
PSA Crypto API specification, so it must stick to the standard type
`psa_key_id_t`. Hence, as long as the specification and Mbed Crypto
are not separate, use the implementation-specific file
`psa/crypto_platform.h` to define `psa_key_id_t` as `psa_key_file_id_t`.
In the library, systematically use `psa_key_file_id_t`.
perl -i -pe 's/psa_key_id_t/psa_key_file_id_t/g' library/*.[hc]
PSA_MAX_PERSISTENT_KEY_IDENTIFIER was actually one plus the maximum
key identifier. Change it to be the maximum value, and change the code
that uses it accordingly.
There is no semantic change here (the maximum value hasn't changed).
This commit only makes the implementation clearer.
