mbedtls_asn1_get_int() and mbedtls_asn1_get_mpi() behave differently
on negative INTEGERs (0200). Don't change the library behavior for now
because this might break interoperability in some applications. Change
the test function to the library behavior.
Fix the test data with negative INTEGERs. These test cases were
previously not run (they were introduced but deliberately deactivated
in 27d806fab4). The test data was
actually wrong: ASN.1 uses two's complement, which has no negative 0,
and some encodings were wrong. Now the tests have correct data, and
the test code rectifies the expected data to match the library
behavior.
mbedtls_asn1_get_int() and mbedtls_asn1_get_mpi() behave differently
on an empty INTEGER (0200). Don't change the library behavior for now
because this might break interoperability in some applications. Write
a test function that matches the library behavior.
Add self-contained ASN.1 parsing tests, so that ASN.1 parsing is not
solely tested through X.509 and TLS.
The tests cover every function and almost complete line coverage in
asn1parse.c.
A few test cases containing negative and edge case INTEGER values are
deliberately deactivated because the historical library behavior is at
odds with official specifications, but changing the behavior might
break interoperability.
Other than that, these tests revealed a couple of minor bugs which
will be fixed in subsequent commits.
