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Diffstat (limited to 'docs/MESHBAY_DESIGN.md')
| -rw-r--r-- | docs/MESHBAY_DESIGN.md | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/docs/MESHBAY_DESIGN.md b/docs/MESHBAY_DESIGN.md index 394dfb5..6e3513d 100644 --- a/docs/MESHBAY_DESIGN.md +++ b/docs/MESHBAY_DESIGN.md @@ -1006,6 +1006,18 @@ a film already playing — a reconnect fetches a fresh one. `meshbay_common/toke holds the two audience strings, shared by the hub that issues and the node that verifies. +**The MNP token also names the node it is for** (`node` claim = that node's +Ed25519 key), and the node refuses one that names a different key. The client +knows the target node's key before it connects and asks for a token bound to it. +This closes the one thing the audience split alone did not: a member's token, +handed to the operator of node A, could otherwise be **replayed to node B** the +member also belongs to — not to read content (that still needs node B's group +key in the proof, which the operator lacks) but to reach node B's **pre-proof +window** and fetch the member's *encrypted* keypair bundle for node B. Binding +the token to node A makes node B refuse it outright. A token that names no node +is still accepted, because the hub only ever mints one for the authenticated +requester, so it grants nothing across accounts. + **Authorization rules:** - `group_id` is **mandatory**. Omitting it once skipped the membership check and @@ -3237,7 +3249,7 @@ had already been asked. | **E7** | **Several named roots** per group, forming one virtual root (§6.2) | | **E8** | **exFAT/NTFS and Windows are the common case.** Linux ships first; that is build order, not population (§10) | | **E9** | **Group-related server state lives on the node. Always** (§1.3) | -| **E10** | **The credential a member presents to a node is not the one the hub API accepts.** A member hands its handshake token to the node operator, who is in the threat model, so it is a short-lived node-audience token (`aud = MNP_AUD`, §5.2), useless at the hub API; the session token (`aud` = hub API) is never disclosed to a node. Before this the member presented its hub session token, so an operator held a live hub credential for the member — enough to enumerate their other groups and act as them at the hub. Closed by the audience split and the MNP 4.0 flag day (§5.6) | +| **E10** | **The credential a member presents to a node is not the one the hub API accepts.** A member hands its handshake token to the node operator, who is in the threat model, so it is a short-lived node-audience token (`aud = MNP_AUD`, §5.2), useless at the hub API; the session token (`aud` = hub API) is never disclosed to a node. Before this the member presented its hub session token, so an operator held a live hub credential for the member — enough to enumerate their other groups and act as them at the hub. The token also **names the node it is for** (`node` claim), so a token captured by one node's operator cannot be replayed to another node the member uses — not even to reach its pre-proof window. Closed by the audience split, the node binding, and the MNP 4.0 flag day (§5.6) | | **O1** | Initial key setup in the pre-proof window — deferred; that window is where C4 and C5b came from | | **O2** | A LAN enrolment door — one endpoint, bounded window, one-time code, closing permanently on success | | **O3** | `device_policy {allow_bundle: false}`, signed by a pinned key — **the mechanism that actually closes C4** (§3.7) | |