* mbedtls-2.16: (28 commits)
Bump version to Mbed TLS 2.16.3
Changelog entry
Check for zero length and NULL buffer pointer
ssl-opt.sh: wait for proxy to start before running the script further
Fix uninitialized variable in x509_crt
HMAC DRBG: Split entropy-gathering requests to reduce request sizes
Fix the license header of hkdf
Add a change log entry
Add a test for mlaformed ECJPAKE context
Fix handling of md failure
Add a test for signing content with a long ECDSA key
Add documentation notes about the required size of the signature buffers
Add missing MBEDTLS_ECP_C dependencies in check_config.h
Change size of preallocated buffer for pk_sign() calls
Adapt ChangeLog
Fix mpi_bigendian_to_host() on bigendian systems
Add ChangeLog entry for new function
Add ChangeLog entry
Correct deterministic ECDSA behavior
Add warning for alternative ECDSA implementations
...
A 0-length buffer for the key is a legitimate edge case. Ensure that
it works, even with buf=NULL. Document the key and keylen parameters.
There are already test cases for parsing an empty buffer. A subsequent
commit will add tests for writing to an empty buffer.
Add checks for null pointers under MBEDTLS_CHECK_PARAMS.
In functions that perform operations with a context, only check if the
context pointer is non-null under MBEDTLS_CHECK_PARAMS. In the default
configuration, unconditionally dereference the context pointer.
In functions that query a context, support NULL as a
pointer-to-context argument, and return the same value as for a
context which has been initialized but not set up.
When writing a private EC key, use a constant size for the private
value, as specified in RFC 5915. Previously, the value was written
as an ASN.1 INTEGER, which caused the size of the key to leak
about 1 bit of information on average, and could cause the value to be
1 byte too large for the output buffer.
