Two bugs that conspired to break interop test 15 once the test 14 OOM
was fixed:
1. **No receive path for standalone PublicMessage proposals.**
wn/openmls publishes a non-admin's `SelfRemove` as a kind:445 carrying
a `PublicMessage(content_type=PROPOSAL)` envelope and waits for an
admin to fold it into the next commit. Quartz's `MarmotInboundProcessor`
answered every such event with `Error("Standalone proposals not yet
supported")` and dropped it. The admin's subsequent commit then
failed with `Commit references unknown proposal (ref not found in
pending proposals)` because nobody had staged the SelfRemove.
Add `MlsGroup.receivePublicMessageProposal(pubMsg)` that:
- rejects mismatched epoch / group_id / sender,
- reconstructs the FramedContentTBS exactly as the proposer did and
verifies the leaf signature,
- verifies the membership_tag against the current epoch's
membership_key (same threat model as inbound PublicMessage commits),
- decodes the inner Proposal (only `SelfRemove` is accepted today —
other types come bundled in commits' `proposals` lists),
- stages the proposal in `pendingProposals` so a later commit can
resolve its `ProposalRef`.
`processPublicMessage` now routes `ContentType.PROPOSAL` through
that helper and returns a new `GroupEventResult.ProposalStaged`
variant (also surfaced as `MarmotIngestResult.ProposalStaged`),
replacing the old hard-error path.
2. **Wrong `ProposalRef` hash input.** RFC 9420 §5.2 specifies that a
`ProposalRef` hashes the **encoded `AuthenticatedContent`** that
delivered the proposal, not the bare `Proposal` struct. Quartz was
hashing `proposal.toTlsBytes()` only — fine for our local-only
flows where commits inline rather than reference our own pending
proposals, but fatal once we needed to match wn's reference to an
inbound proposal.
Extend `PendingProposal` with an optional `authenticatedContentBytes`
field. The standalone-proposal receive path captures the full
`wire_format || FramedContent || FramedContentAuthData` envelope at
stage time. The reference-resolution code in `processCommitInner`
prefers those bytes when present and falls back to the bare-proposal
hash for locally-proposed entries (which never get referenced
today).
Marmot interop score: 14/16 → 15/16 (test 9 — amy's kind:7 reaction
triggers a `SecretReuseError` on B's wn — is unrelated to this path
and remains for follow-up).
https://claude.ai/code/session_013VYkpz8P1mPh9Ejxy9anhJ
Claude
9d912ad82a