Deprecate the module-specific XXX_HW_ACCEL_FAILED and
XXX_FEATURE_UNAVAILABLE errors, as alternative implementations should now
return `MBEDTLS_ERR_PLATFORM_HW_FAILED` and
`MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED`.
Change the import/export format of private elliptic curve keys from
RFC 5915 to the raw secret value. This commit updates the format
specification and the import code, but not the export code.
Context:
The macro `MBEDTLS_ECP_BUDGET()` is called before performing a
number of potentially time-consuming ECC operations. If restartable
ECC is enabled, it wraps a call to `mbedtls_ecp_check_budget()`
which in turn checks if the requested number of operations can be
performed without exceeding the maximum number of consecutive ECC
operations.
Issue:
The function `mbedtls_ecp_check_budget()` expects a the number
of requested operations to be given as a value of type `unsigned`,
while some calls of the wrapper macro `MBEDTLS_ECP_BUDGET()` use
expressions of type `size_t`.
This rightfully leads to warnings about implicit truncation
from `size_t` to `unsigned` on some compilers.
Fix:
This commit makes the truncation explicit by adding an explicit cast
to `unsigned` in the expansion of the `MBEDTLS_ECP_BUDGET()` macro.
Justification:
Functionally, the new version is equivalent to the previous code.
The warning about truncation can be discarded because, as can be
inferred from `ecp.h`, the number of requested operations is never
larger than 1000.
Add extern "C" wrappers around type and function declarations to enable C++
interoperability of the driver header. This is done so that the driver
functions and types can be used or implmented by C++ code.
Convert PSA Crypto driver model structs to typedefs so that the `struct`
name doesn't need to be used and for consistent style with other PSA
structures.
The file crypto_driver.h was not using the header guard style as other PSA
Crypto header files. Remove the `__` prefix and suffix. Use C-style
comments for the end-of-guard comment.
The driver model's "encrypt or decrypt" type, encrypt_or_decrypt_t, is
publicly exposed and needs to have a `psa_` prefix in order to properly
communicate that it is part of the PSA driver model.
The `pcd_` prefix is ambiguous and does not make it clear that the types
and symbols are standardized by PSA. Replace `pcd_` with a prefix that can
be shared with all PSA drivers, `psa_drv_`.
"Driver APIs" can be interpreted to mean APIs used when you want to write a
driver, not the set of functions you implement to make a driver. See
https://www.kernel.org/doc/html/latest/driver-api/index.html "The kernel
offers a wide variety of interfaces to support the development of device
drivers."
As such, we are renaming "Driver API" to "Driver Model" and updating our
work so far to reflect this change.
Add comments noting that the maximum length of a MAC must fit in
PSA_ALG_MAC_TRUNCATION_MASK. Add a unit test that verifies that the
maximum MAC size fits.
Rename the PLATFORM HW error, to avoid ABI breakage with Mbed OS.
The value changed as well, as previous value was not in the range of
Mbed TLS low level error codes.
