ESP32C2 has a hardware ECC accelerator that supports NIST P-192 and NIST P-256 curves,
which can increase the performance of the point multiplication and point
verification operation.
Provision is also added to fallback to software implementation in
case the curve is not from the supported curves
For exponential mod (API mbedtls_mpi_exp_mod) operation, some ESP target
chips needs to have ability for both hardware and software implementation.
Hardware implementation provided performance advantage but it can only
support upto 3072 bit operations (e.g., ESP32-C3) and hence we fallback
to software implementation in such cases (e.g., 4096 bit operations).
Earlier this was handled using linker "--wrap" flag but that does not
work in all scenarios as API `mbedtls_mpi_exp_mod` is being used in
same tranlation (compilation unit).
This approach was found to be next best option with minimal changes in
mbedTLS library.
Running `generate_ssl_debug_helpers.py` generates both
`ssl_debug_helpers_generated.c` and `ssl_debug_helpers_generated.h`.
List the `.h` file as well as the `.c` file in `check-generated-files.sh` so
that `check-generated-files.sh -u` will complain if it isn't up to date.
List it in `Makefile` and `CMakeLists.txt` so that parallel builds know when
to wait until the `.h` file is present. In `Makefile`, declare the `.c` file
as depending on the `.h` file for order. This way, a dependency for either
will wait until the `.h` file is present, and since the `.h` file is
generated after the `.c` file, this guarantees that the `.c` file is
present.
This fixes random failures of `make -j` from a fresh checkout.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Zeroize temporary buffers used to sanity-check the signature.
If there is an error, overwrite the tentative signature in the output
buffer.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Declare mbedtls_md functions as MBEDTLS_CHECK_RETURN_TYPICAL, meaning that
their return values should be checked.
Do check the return values in our code. We were already doing that
everywhere for hash calculations, but not for HMAC calculations.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Zeroize local MAC variables used for CBC+HMAC cipher suites. In encryption,
this is just good hygiene but probably not needed for security since the
data protected by the MAC that could leak is about to be transmitted anyway.
In DTLS decryption, this could be a security issue since an adversary could
learn the MAC of data that they were trying to inject. At least with
encrypt-then-MAC, the adversary could then easily inject a datagram with
a corrected packet. TLS would still be safe since the receiver would close
the connection after the bad MAC.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
As we have now a minimal viable implementation of TLS 1.3,
let's remove EXPERIMENTAL from the config option enabling
it.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
