openssl-3.0-fips does not support chachapoly

[lrstewart]

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Problem:

s2n-tls does not support chachapoly when built with openssl-3.0-fips. It isn't impossible to support chachapoly, but we'd need to add support for fetching the algorithm from the non-fips provider.

Need By Date:

No known need by date.

Solution:

Instead of using the "EVP_chacha20_poly1305()" const in https://github.com/aws/s2n-tls/blob/main/crypto/s2n_aead_cipher_chacha20_poly1305.c, we would need to call EVP_CIPHER_fetch to retrieve the cipher with the "-fips" property string. That will use the non-fips provider instead of the fips provider.

• 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?