Availability of sufficient incoming data should be checked when
it is needed, which is in mbedtls_ssl_fetch_input(), and this
function has the necessary bounds checks in place.
The check is in terms of the internal input buffer length and is
hence likely to be originally intended to protect against overflow
of the input buffer when fetching data from the underlying
transport in mbedtls_ssl_fetch_input(). For locality of reasoning,
it's better to perform such a check close to where it's needed,
and in fact, mbedtls_ssl_fetch_input() _does_ contain an equivalent
bounds check, too, rendering the bounds check in question redundant.
mbedtls_ssl_decrypt_buf() asserts that the passed transform is not NULL,
but the function is only invoked in a single place, and this invocation
is clearly visible to be within a branch ensuring that the incoming
transform isn't NULL. Remove the assertion for the benefit of code-size.
The previous code performed architectural maximum record length checks
both before and after record decryption. Since MBEDTLS_SSL_IN_CONTENT_LEN
bounds the maximum length of the record plaintext, it suffices to check
only once after (potential) decryption.
This must not be confused with the internal check that the record
length is small enough to make the record fit into the internal input
buffer; this is done in mbedtls_ssl_fetch_input().
Drivers that allow destroying a key must have a destroy method. This
test bug was previously not caught because of an implementation bug
that lost the error triggered by the missing destroy method.
Adopt a simple method for tracking whether there was a failure: each
fallible operation sets overall_status, unless overall_status is
already non-successful. Thus in case of multiple failures, the
function always reports whatever failed first. This may not always be
the right thing, but it's simple.
This revealed a bug whereby if the only failure was the call to
psa_destroy_se_key(), i.e. if the driver reported a failure or if the
driver lacked support for destroying keys, psa_destroy_key() would
ignore that failure.
For a key in a secure element, if creating a transaction file fails,
don't touch storage, but close the key in memory. This may not be
right, but it's no wronger than it was before. Tracked in
https://github.com/ARMmbed/mbed-crypto/issues/215
When a key slot is wiped, a copy of the key material may remain in
operations. This is undesirable, but does not violate the safety of
the code. Tracked in https://github.com/ARMmbed/mbed-crypto/issues/86
compat.sh used to skip OpenSSL altogether for DTLS 1.2, because older
versions of OpenSSL didn't support it. But these days it is supported.
We don't want to use DTLS 1.2 with OpenSSL unconditionally, because we
still use legacy versions of OpenSSL to test with legacy ciphers. So
check whether the version we're using supports it.
Add a flow where the key is imported or fake-generated in the secure
element, then call psa_export_public_key and do the software
verification with the public key.
Factor common code of ram_import and ram_fake_generate into a common
auxiliary function.
Reject key types that aren't supported by this test code.
Report the bit size correctly for EC key pairs.
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".
Let psa_start_key_creation know what type of key creation this is. This
will be used at least for key registration in a secure element, which
is a peculiar kind of creation since it uses existing key material.
Without any -O option, the default is -O0, and then the assembly code
is not used, so this would not be a non-regression test for the
assembly code that doesn't build.
