Part of the record encryption/decryption tests is to gradually
increase the space available at the front and/or at the back of
a record and observe when encryption starts to succeed. If exactly
one of the two parameters is varied at a time, the expectation is
that encryption will continue to succeed once it has started
succeeding (that's not true if both pre- and post-space are varied
at the same time).
Moreover, previously the test would take turns when choosing which
transform should be used for encryption, and which for decryption.
With the introduction of the CID feaature, this switching of transforms
doesn't align with the expectation of eventual success of the encryption,
since the overhead of encryption might be different for the parties,
because both parties may use different CIDs for their outgoing records.
This commit modifies the tests to not take turns between transforms,
but to always use the same transforms for encryption and decryption
during a single round of the test.
This commit adds tests to check the behavior of the record encryption
routine `ssl_encrypt_buf` when the buffer surrounding the plaintext is
too small to hold the expansion in the beginning and end (due to IV's,
padding, and MAC).
Each test starts successively increases the space available at the
beginning, end, or both, of the record buffer, and checks that the
record encryption either fails with a BUFFER_TOO_SMALL error, or
that it succeeds. Moreover, if it succeeds, it is checked that
decryption succeeds, too, and results in the original record.
This commit adds tests exercising mutually inverse pairs of
record encryption and decryption transformations for the various
transformation types allowed in TLS: Stream, CBC, and AEAD.
Add a test case calling ssl_set_hostname twice to test_suite_ssl.
When run in CMake build mode ASan, this catches the current leak,
but will hopefully be fine with the new version.
