Tls 1.3 ClientHello legacy_session_id as zero length vector alignment

Question

Looking at tls 1.3 draft 23: https://datatracker.ietf.org/doc/html/draft-ietf-tls-tls13-23

Section 4.1.2 shows, for a freshly established connection (no previous session from tls 1.2 or earlier) the legacy_session_id for ClientHello must be a zero length variable vector, which allows a max length of 32.

My interpretation of section 3.3 makes this zero length vector a single byte of value 0, followed by a zero byte-length entry, ie followed by nothing.

This seems to misalign structs comprised of the ClientHello. Is this correct?

Answer 1

Yes exactly. Nothing in the TLS spec is ever required to align on a boundery of a power of 2 in fact.