Verifying QUIC implementations using Ivy

Abstract: QUIC is a new transport protocol combining the reliability and congestion control features of TCP with the security features of TLS. One of the main challenges with QUIC is to guarantee that any of its implementation follows the IETF specification. This challenge is particularly appealing as the specification is written in textual language, and hence may contain ambiguities. In a recent work, McMillan and Zuck proposed a formal representation of part of draft-18 of the IETF specification. They also showed that this representation made it possible to efficiently generate tests to stress four implementations of QUIC. Our first contribution is to complete and extend the formal representation from draft-18 to draft-29. Our second contribution is to test seven implementations of both QUIC client and server. Our last contribution is to show that our tool can highlight ambiguities in the QUIC specification, for which we suggest paths to corrections