From bce962c39fcb2d124506e33f77c3ca9082f145dd Mon Sep 17 00:00:00 2001 From: Christophe Besson Date: Fri, 25 Sep 2026 14:53:42 +0200 Subject: fix(hub): present a node-audience token in the handshake, not the hub session token MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit A member authenticated to a node in the MNP handshake with its hub *session* token — scope=user, valid at the hub API for hours. A node operator is in the threat model, so this handed them a live hub credential for the member: enough to enumerate the member's other groups, act as them, and (before the previous commit closed it) take the account over. The node genuinely needs a hub-signed membership assertion, so the fix is to make that a separate credential that opens nothing at the hub API. Two audiences signed by the one hub key (meshbay_common/tokens.py): - HUB_API_AUD — session tokens (login, device-auth, node-auth, refresh), used for hub calls and signaling. decode_access_token now binds this audience, so an MNP token cannot be replayed against the hub API. - MNP_AUD — a short-lived token a member presents to a node and nothing else, from POST /v1/nodes/mnp-token. authorize_token now binds this audience, so a session token presented to a node is refused. This closes the disclosure. The node's own self-decode (hub_client.py) reads its node token with audience=HUB_API_AUD. The client fetches the MNP token inside transport.connect() (and on every reconnect) using the session token, so callers are unchanged and signaling keeps using the session token. No regression to a long session: the MNP token is checked once, at the handshake, before any proof — a film already playing is not re-authenticated, so a 15-minute token does not interrupt a 4-hour film; reconnects refetch a fresh one. Denylist and membership checks are unchanged (the MNP token carries sub/jti/groups). Tests: authorize_token refuses a session/no-audience token and accepts an MNP token; the hub API refuses an MNP token; POST /v1/nodes/mnp-token is minted only for a member's own session. Verified red-before/green-after; common, node and hub suites green (the pre-existing test_cli_golden failure is an argparse/pytest prog artifact unrelated to this change). Still to do before deploy (B2): bump the MNP version and client.minimum so a stale desktop client is told to update rather than getting a handshake refusal, update docs/MESHBAY_DESIGN.md and MESHBAY_NODE_PROTOCOL.md, and validate against a real node locally, then deploy hub+node+SPA atomically. Co-Authored-By: Claude Opus 4.8 --- packages/meshbay-hub/tests/test_hub_api.py | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'packages/meshbay-hub/tests/test_hub_api.py') diff --git a/packages/meshbay-hub/tests/test_hub_api.py b/packages/meshbay-hub/tests/test_hub_api.py index 2afd27b..162b074 100644 --- a/packages/meshbay-hub/tests/test_hub_api.py +++ b/packages/meshbay-hub/tests/test_hub_api.py @@ -3,6 +3,7 @@ Integration tests for the Hub API. Uses SQLite in-memory + httpx.AsyncClient — no PostgreSQL, no network. """ +from meshbay_common.tokens import HUB_API_AUD from datetime import UTC import pytest @@ -142,7 +143,7 @@ async def test_jwt_offline_verify(client, hub_key_path): r_pk = await client.get("/v1/hub/pubkey") hub_pk_pem = r_pk.json()["pk_hub_pem"].encode() - decoded = pyjwt.decode(token, hub_pk_pem, algorithms=["EdDSA"]) + decoded = pyjwt.decode(token, hub_pk_pem, algorithms=["EdDSA"], audience=HUB_API_AUD) assert "jti" in decoded # mandatory # The token carries no user key. It used to, and the node recorded it as the # uploader's identity — so whoever issued tokens decided who could delete a @@ -339,7 +340,7 @@ async def test_jwt_contains_groups_claim(client): token_pre = r.json()["access_token"] r_pk = await client.get("/v1/hub/pubkey") hub_pk = r_pk.json()["pk_hub_pem"].encode() - decoded_pre = pyjwt.decode(token_pre, hub_pk, algorithms=["EdDSA"]) + decoded_pre = pyjwt.decode(token_pre, hub_pk, algorithms=["EdDSA"], audience=HUB_API_AUD) assert decoded_pre["groups"] == [] # Alice creates a group and adds Bob @@ -359,13 +360,13 @@ async def test_jwt_contains_groups_claim(client): r = await client.post("/v1/users/login", json={ "username": "grp_bob_test", "password": "bobpass99"}) token_post = r.json()["access_token"] - decoded_post = pyjwt.decode(token_post, hub_pk, algorithms=["EdDSA"]) + decoded_post = pyjwt.decode(token_post, hub_pk, algorithms=["EdDSA"], audience=HUB_API_AUD) assert group_id in decoded_post["groups"] # Alice (admin) should also have the group in her JWT r = await client.post("/v1/users/login", json={ "username": "grp_alice", "password": "alicepass99"}) - decoded_alice = pyjwt.decode(r.json()["access_token"], hub_pk, algorithms=["EdDSA"]) + decoded_alice = pyjwt.decode(r.json()["access_token"], hub_pk, algorithms=["EdDSA"], audience=HUB_API_AUD) assert group_id in decoded_alice["groups"] -- cgit v1.2.3