fix: resource limits, signaling authz, node admin UI token

2026-08-13T09:18:24Z

Phase 11.5 — findings H6, C4 (partial), and milestone 11.5.3. H6 — resource exhaustion. Several paths let one peer degrade or stall a node: * the DataChannel frame limit was a flat 64 MB applied BEFORE authentication, so an unauthenticated peer could announce a huge frame and dribble bytes into it. Unauthenticated peers now get 64 KB; the large budget is granted only after the GEK proof, where it is needed for uploads. * _do_stream_segment ran subprocess.run(..., timeout=30) directly in the event loop, stalling the entire daemon — every peer, every group — for up to thirty seconds per request. Now async, with a timeout and process kill. * ffmpeg was spawned per stream request with no cap. Both streaming paths now share a transport-wide semaphore. * POST /v1/nodes/{id}/webrtc/offer was reachable by any authenticated user for any node, with no membership check and no rate limit, making the target node allocate an aiortc PeerConnection and gather ICE on demand — remote resource exhaustion against a third party's machine. Now rate limited, capped per user, SDP size bounded, and the caller must share an active group with the node. That also closes the H4 gap where signaling ignored group status. * POST /v1/nodes/{id}/incoming took peer_ip verbatim, so any user could make an arbitrary node emit UDP packets to an address of their choosing. The probe target must now match the caller's own source address. C4 (partial) — the pre-proof bundle window. GEK and keypair bundle fetches are served before the GEK proof by necessity: the client needs its wrapped bundle in order to compute the proof. That window is a disclosure surface a hub can reach by forging a JWT. Bounded to 4 fetches per session and audited as "pre_proof_fetch". The real fix is removing remote keypair bundles entirely, which belongs to the native client (Phase 13.3). 11.5.3 — the node admin UI was unauthenticated because it binds loopback. But any local process can reach it, and so can a page in the operator's browser via DNS rebinding — and this API re-initialises group keys and reads the audit log. H2 showed script execution there equals full control. Now gated by a per-run token, printed at startup, accepted as ?t= or X-MeshBay-Token. One test needed rewriting rather than adding: the first version asserted "subprocess.run(" was absent from the source, which also matched the comment documenting the old behaviour. It now parses the AST and checks the property. Tests: 121 node, 142 hub+common. Regression suite 47 node + 10 hub. Co-Authored-By: Claude Opus 5

feat: Phase 9.1–9.5 — WebRTC DataChannel transport for browser P2P

2026-08-10T20:12:59Z

Browser clients can now connect P2P to nodes behind residential NAT via WebRTC DataChannel with ICE/STUN. Validated on SFR Port-Restricted Cone NAT + 4G CGNAT across three scenarios (WiFi LAN, 4G IPv6, 4G IPv4 STUN). No TURN relay needed. Hub serves only as signaling relay (<1 KB). New files: - webrtc_server.py: aiortc-based WebRTC transport (node side) - signaling.py: SDP/ICE relay endpoint (hub side) - transport.js: browser WebRTC client with msgpack framing - webrtc-test.html: spike test page for browser→NAT→node validation - test_webrtc_transport.py: 4 tests (handshake, file transfer, auth, guard) - meshbay-draft-v4.md: architecture spec updated for web client Modified: - hub_client.py: WebRTC offer handling via hub WebSocket - revocation.py: node_id from WS auth + webrtc_answer routing - pyproject.toml: aiortc>=1.9 dependency 123 tests passing (117 existing + 6 new). Co-Authored-By: Claude Opus 4.6

meshbay.git/packages/meshbay-hub/src/meshbay_hub/api/signaling.py, branch 0.2

fix: resource limits, signaling authz, node admin UI token

feat: Phase 9.1–9.5 — WebRTC DataChannel transport for browser P2P