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.
In preparation for the import/export format change for private
elliptic curve keys from RFC 5915 to the raw secret value,
remove ASN.1-based sanity checks. For the raw secret value, most byte
strings of the correct length are valid (the details depend on the
curve), so as a sanity check, just check the length.
In preparation for the import/export format change for private
elliptic curve keys from RFC 5915 to the raw secret value, transform the
test data to the new format.
Tests will not pass until the implementation has been changed to the
new format and some test cases and test functions have been adjusted.
I used the script below to look for lines containing a
PSA_KEY_TYPE_ECC_KEYPAIR and change the first hex string in the
line with an ASN.1 header that looks like the beginning of an RFC 5915
ECPrivateKey. This always happens to be a private key input.
perl -a -F: -i -pe 'sub pad { local ($_) = @_; s/^00// if length == $digits + 2; die if length > $digits; sprintf("\"%0${digits}s\"", $_) } if ($F[0] !~ /\W/ && /:PSA_KEY_TYPE_ECC_KEYPAIR\( *PSA_ECC_CURVE_[A-Z_]+([0-9]+)/) {$digits = int(($1+7)/8)*2; s/"30(?:[0-7].|81..|82....)02010104(..)([0-9a-f]+)"/pad(substr($2, 0, hex($1)*2))/ie}' tests/suites/test_suite_psa_crypto.data
In the test function for export_public_key, don't just check the
length of the result. Compare the actual result to the expected
result.
Take an extra argument that allows using an export buffer that's
larger or smaller than needed. Zero is the size given by
PSA_KEY_EXPORT_MAX_SIZE.
Don't check the output of psa_get_key_information. That's useful in
import_export because it tests both import and export, but not in
import_export_public_key whose goal is only to test public key export.
This commit adjusts the existing test data but does not add new test
cases.
This commit modifies a bounds check in `mbedtls_ecp_check_budget()` to
be correct even if the requested number of ECC operations would overflow
the operation counter.
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.
Key derivation test now uses an indirect way to test generator validity
as the direct way previously used isn't compatible with the PSA IPC
implementation. Additional bad path test for the generator added
to check basic bad-path scenarios.
