feat: tls 1.3 handshake message parsers - #436
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mirror the senders in message_build.zig — server_hello, encrypted_ extensions, certificate (single-leaf only), certificate_verify, finished, certificate_request — plus a small nextMessage iterator since the server packs several handshake messages into one record. narrow profile (AES-256-GCM / X25519 / ECDSA-SHA256) so the parsers reject anything the rest of the stack can't handle anyway. eight round-trip tests against the existing builders cover every parser, including the certificate_request scheme-list check.
This was referenced Jun 9, 2026
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summary
second PR-4 chunk (after #435). adds the TLS 1.3 handshake message
parsers the client driver will need, plus a small iterator for walking
the packed handshake stream that comes out of a single decrypted record.
no behavior change — these are pure decoders. mirrors the senders in
message_build.zigone-for-one so a builder + parser test covers eachmessage format.
what's in here
src/tls/handshake/message_parse.zigwith:nextMessage(stream, &pos)— walks the concatenated stream ofhandshake messages, returns each as
{ msg_type, body, raw }(rawis what feeds the transcript hash on both sides)
parseServerHello— extracts server_random, X25519 share; rejectsanything that isn't TLS 1.3 / AES-256-GCM / X25519
parseEncryptedExtensions— selected ALPN (or null)parseCertificateMessage— leaf cert DER (single-cert chain only,matches what we issue)
parseCertificateVerify— algorithm code + signature DERparseFinished— verify_data sliceparseCertificateRequest— context + raw SignatureSchemeList, plusa
certRequestOffersEcdsaP256Sha256helper for the only scheme weactually understand
tests
eight round-trip tests (builder → parser) cover every message type plus
a packed-stream walk and a truncated-stream rejection.
not in this PR
CertificateRequest+ client-cert verify pathstill security-sensitive (it's the wire format), so no auto-merge —
landing in chunks per your earlier instruction.