Quartz:
- processWelcome now enforces hash(ratchet_tree) == GroupContext.tree_hash
and verifies the joiner-derived confirmation_tag matches GroupInfo's,
closing the gap where a tampered but-signed GroupInfo could diverge
the joiner's epoch secrets.
- externalJoin does the equivalent tree_hash check.
- Promoted constantTimeEquals to a file-level helper so the companion
object (processWelcome) can use it alongside instance methods.
Tests:
- New MlsGroupNegativeTest exercises every authenticity knob on inbound
commits: tampered confirmation_tag, bit-flipped signature, spoofed
senderLeafIndex, wrong wire_format, empty confirmation_tag, and
tampered/missing membership_tag — each must throw and leave the
receiving group's epoch unchanged (atomic-rollback regression cover).
- Fixed stale jvmAndroidTest references to the removed `selfRemove()`
helper — use `buildSelfRemoveProposalMessage()` (now Pair-returning).
Interop harness:
- Adds tests 14–16 as inverted-role scaffolding (wn drives, amy receives).
Currently recorded as SKIP with explicit notes:
14 / 15 block on filtered-direct-path UpdatePath support in
quartz's applyUpdatePath (RFC 9420 §7.7 path compression).
16 blocks on a createdAt-sorted KeyPackage fetch path — the current
fetchFirst-based fetcher is non-deterministic on relay order.
Preserves the test functions so they start running the moment those
gaps are closed.
Claude
816d253a65