Handshake Traces for TLS1.3 are for Stateful Session Resumption

[maddeleine]

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:

We use the TLS 1.3 handshake traces RFC to test s2n features. The psk handshake traces in this RFC are technically for stateful session resumption. S2N has not implemented stateful session resumption, only stateless session resumption. We still use the handshake traces to check our psk implementation is correct, however, some of our tests have a hack in them where a psk is set to S2N_PSK_TYPE_RESUMPTION, but the psk_params value is set to S2N_PSK_TYPE_EXTERNAL. This is so that we can skip decrypting and deserializing the known value psk, while still getting some testing benefits of using the handshake traces.

Solution:

When we implement stateful session resumption, the tests should work without this hack.

• Does this change what S2N sends over the wire? No
• Does this change any public APIs? No
• Which versions of TLS will this impact?
  N/A

Requirements / Acceptance Criteria:

The psk type and psk_params type should match for all tests.

• RFC links: N/A
• Related Issues: N/A
• Will the Usage Guide or other documentation need to be updated? No
• Testing: Unit tests
  • Will this change trigger SAW changes? No
  • Should this change be fuzz tested? No

Out of scope:

N/A