Add support for fips mode with Openssl-3

[lrstewart]

Security issue notifications

If you discover a potential security issue in s2n we ask that you notify
AWS Security via our vulnerability reporting page. Please do not create a public github issue.

Problem:

Currently s2n-tls only supports fips via awslc. We don't respect openssl providers, which is how fips is implemented in Openssl-3.

Solution:

Make it possible to operate s2n-tls in a fips-compatible way when built with Openssl-3

• Does this change what S2N sends over the wire? If yes, explain.
• Does this change any public APIs? If yes, explain.
• Which versions of TLS will this impact?

Requirements / Acceptance Criteria:

What must a solution address in order to solve the problem? How do we know the solution is complete?

• RFC links: Links to relevant RFC(s)
• Related Issues: Link any relevant issues
• Will the Usage Guide or other documentation need to be updated?
• Testing: How will this change be tested? Call out new integration tests, functional tests, or particularly interesting/important unit tests.
  • Will this change trigger SAW changes? Changes to the state machine, the s2n_handshake_io code that controls state transitions, the DRBG, or the corking/uncorking logic could trigger SAW failures.
  • Should this change be fuzz tested? Will it handle untrusted input? Create a separate issue to track the fuzzing work.

Out of scope:

Is there anything the solution will intentionally NOT address?