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Close forged-directness link-rebind DoS on DM routing (#1421)
* Gate connected-link trust on a secure session; deny forged direct announces the connected shortcut
Residual gap after the rotation-heal containment (#1401): "verified
direct" announces prove the signature but not directness — TTL is
unsigned — so a malicious connected peer can replay a victim's fresh
announce with its TTL restored. When the victim has no live link, the
replayer's link rebinds to the victim's ID and reads as "connected",
and MessageRouter's connected fast-path then trusts it outright: every
DM stalls on a Noise handshake the replayer can never complete and is
silently lost while showing "sent".
Router-level trust gate (no wire change):
- Transport gains canDeliverSecurely(to:) — BLE answers with an
established Noise session; Nostr keeps its prompt-delivery predicate;
the protocol default forwards to canDeliverPromptly for transports
without a forgeable link layer.
- MessageRouter.sendPrivate only trusts a connected link outright when
it can deliver securely; otherwise it still sends (kicking the
handshake on a genuine link) but retains a copy and hands a sealed
copy to couriers, like the reachable path. flushOutbox gets the same
gate so a flush over an insecure link resends instead of dropping the
retained copy.
Presence hardening (defense in depth): a "direct" announce arriving on
a link already bound to a different peer no longer shortcuts the
claimed peer into "connected" — only real link state does. Genuine
first-contact and direct announces are unaffected; only the ambiguous
heal path loses the forgeable shortcut.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
* Harden the insecure-link outbox bound; document the second-replay presence gap and the courier metadata tradeoff
Review follow-ups on the canDeliverSecurely gate:
- flushOutbox no longer counts connected-but-insecure flushes toward the
maxSendAttempts drop: the message was actually transmitted over a live
link, so a peer whose Noise handshake stalls across reconnect flapping
must not burn through the cap and lose the store-and-forward copy the
gate exists to preserve. Retention stays bounded by the 24h outbox TTL
and the per-peer FIFO cap; acks still clear it. Attempt-counting stays
for reachable-only (heuristic) sends. Regression test: >8 connected-
insecure flushes keep the retained copy, drop callback never fires.
- Document the known second-replay presence gap: linkBoundToOtherPeer
reads the binding before rebindLinkAfterVerifiedDirectAnnounce steals
the link, so once a first replay has rebound a link to an absent
victim's ID, a second replay marks the victim connected. Presence
display only — DMs stay on the retain+courier path via the router
gate. Not closed at the announce layer because the post-rebind state
is indistinguishable from a legitimate rotation/reconnect heal (a
supported, field-verified flow). Covered by a two-announce test.
- Note the accepted courier-spray metadata tradeoff at the connected-
insecure send: nearby verified peers receive a sealed copy (they learn
a DM exists, never its content), cleared on ack.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
* Promote a healed rotation to connected; normalize the secure-delivery probe; retain Codable properties in Periphery
Codex review follow-ups on 5017c232:
- P1: a legitimate rotation announce necessarily arrives on a link still
bound to the OLD peer ID, so the linkBoundToOtherPeer denial stored the
new identity as disconnected — and the rebind only fixed link state,
never the registry. A healed rotation then read as disconnected until
the peer happened to announce again. rebindLinkAfterVerifiedDirect-
Announce now promotes the rebound identity to connected after the
containment checks pass (registry markConnected + topology/snapshot/
peer-list refresh; the .peerConnected UI event already fired from the
announce path). This consciously moves the forged-presence residue
from second-replay to first-successful-rebind — bounded by the rebind
containment (never steals a live identity, one rebind per link per
cooldown) and still display-only: DMs stay gated on canDeliverSecurely.
Comments and the pinned tests updated; new regression test covers
rotate-on-open-link -> rebind -> isPeerConnected(new) == true.
- P2: BLEService.canDeliverSecurely probed the Noise session with the
peer ID as given, but sessions are keyed by the short wire ID — a send
keyed by the full 64-hex Noise key (favorites resolution) misread an
established session as insecure and needlessly retained + couriered
every DM until ack. Normalize with toShort() like isPeerConnected.
Test drives a real XX handshake and asserts both ID forms pass.
- Periphery: the PrekeyBundleStore.StoredBundle.noiseKey "assign-only"
flake fired again and slipped past its baselined USR (read exists in
loadFromDisk; the indexer intermittently misses it). Replace the
baseline entry with retain_codable_properties: true — deterministic,
and a truly-dead Codable field is a persisted-format change anyway.
Local periphery scan --strict: no unused code detected.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
---------
Co-authored-by: jack <jackjackbits@users.noreply.github.com>
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
This commit is contained in:
jack
co-authored by
jack
Claude Opus 4.8
jack
Claude Opus 4.8
parent
c8479c15e3
commit
b7c6f42b3a
@@ -8,6 +8,7 @@ struct BLEAnnounceHandlerTests {
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var existingNoisePublicKey: Data?
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var signatureValid = true
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var linkState: (hasPeripheral: Bool, hasCentral: Bool) = (false, false)
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var linkBoundToOtherPeer = false
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var upsertResult = BLEPeerAnnounceUpdate(isNewPeer: false, wasDisconnected: false, previousNickname: nil)
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var dedupSeenIDs: Set<String> = []
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var shouldEmitReconnectLogResult = true
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@@ -41,6 +42,7 @@ struct BLEAnnounceHandlerTests {
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return recorder.signatureValid
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},
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linkState: { _ in recorder.linkState },
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linkBoundToOtherPeer: { _, _ in recorder.linkBoundToOtherPeer },
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withRegistryBarrier: { body in
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recorder.barrierCount += 1
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body()
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@@ -334,6 +336,105 @@ struct BLEAnnounceHandlerTests {
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#expect(recorder.afterglowDelays.count == 1)
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}
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/// TTL is unsigned, so a replayed announce with its TTL restored looks
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/// "direct" — but it arrives on a link another peer already owns. That
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/// link must not shortcut the (possibly absent) claimed peer into
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/// "connected".
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@Test
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func directAnnounceOnLinkBoundToAnotherPeerDoesNotMarkConnected() throws {
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let now = Date(timeIntervalSince1970: 1_000)
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let noiseKey = Data(repeating: 0x88, count: 32)
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let peerID = PeerID(publicKey: noiseKey)
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let packet = try makeAnnouncePacket(
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noisePublicKey: noiseKey,
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peerID: peerID,
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timestamp: timestamp(now),
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signature: Data(repeating: 0xEE, count: 64)
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)
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let recorder = Recorder()
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recorder.linkBoundToOtherPeer = true
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recorder.upsertResult = BLEPeerAnnounceUpdate(isNewPeer: true, wasDisconnected: false, previousNickname: nil)
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let handler = makeHandler(recorder: recorder, now: now)
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let result = handler.handle(packet, from: peerID)
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#expect(result?.isDirectAnnounce == true)
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#expect(result?.isVerified == true)
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#expect(recorder.upsertCalls.count == 1)
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#expect(recorder.upsertCalls.first?.isConnected == false)
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}
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/// A peer with its own live link stays connected even when a copy of its
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/// announce arrives on someone else's link.
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@Test
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func directAnnounceOnForeignLinkKeepsPeerWithOwnLinkConnected() throws {
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let now = Date(timeIntervalSince1970: 1_000)
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let noiseKey = Data(repeating: 0x99, count: 32)
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let peerID = PeerID(publicKey: noiseKey)
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let packet = try makeAnnouncePacket(
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noisePublicKey: noiseKey,
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peerID: peerID,
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timestamp: timestamp(now),
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signature: Data(repeating: 0xEE, count: 64)
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)
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let recorder = Recorder()
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recorder.linkBoundToOtherPeer = true
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recorder.linkState = (hasPeripheral: false, hasCentral: true)
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let handler = makeHandler(recorder: recorder, now: now)
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handler.handle(packet, from: peerID)
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#expect(recorder.upsertCalls.count == 1)
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#expect(recorder.upsertCalls.first?.isConnected == true)
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}
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/// Documents the handler's contract around the rebind: the
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/// linkBoundToOtherPeer read reflects the binding BEFORE the rebind runs,
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/// so a replayed "direct" announce on someone else's link is denied the
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/// connected shortcut — presence only flips via the rebind itself
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/// (BLEService promotes the new owner after a successful, containment-
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/// checked rebind) or via a later announce arriving on the now-rebound
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/// link, as simulated here. Either way the residue is presence display
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/// only — DMs remain gated on canDeliverSecurely, so without a Noise
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/// session they take the retain + courier path (see MessageRouterTests
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/// .sendPrivate_connectedWithoutSecureSessionRetainsAndDepositsWithCourier).
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@Test
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func secondReplayedDirectAnnounceAfterRebindMarksAbsentPeerConnected() throws {
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let now = Date(timeIntervalSince1970: 1_000)
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let noiseKey = Data(repeating: 0xA1, count: 32)
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let victim = PeerID(publicKey: noiseKey)
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let packet = try makeAnnouncePacket(
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noisePublicKey: noiseKey,
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peerID: victim,
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timestamp: timestamp(now),
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signature: Data(repeating: 0xEE, count: 64)
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)
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let recorder = Recorder()
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let handler = makeHandler(recorder: recorder, now: now)
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// First replay: the link still belongs to the replayer and the victim
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// has no live link of its own — the connected shortcut is denied.
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recorder.linkBoundToOtherPeer = true
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recorder.linkState = (hasPeripheral: false, hasCentral: false)
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handler.handle(packet, from: victim)
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#expect(recorder.upsertCalls.count == 1)
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#expect(recorder.upsertCalls.first?.isConnected == false)
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// The rebind then binds the replayer's link to the victim's ID (the
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// rotation-heal path, containment-checked in BLEService). A second
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// replay now finds the link owned by the claimed peer …
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recorder.linkBoundToOtherPeer = false
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recorder.linkState = (hasPeripheral: false, hasCentral: true)
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handler.handle(packet, from: victim)
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// … and the absent victim reads as connected: the residual gap.
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#expect(recorder.upsertCalls.count == 2)
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#expect(recorder.upsertCalls.last?.isConnected == true)
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}
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@Test
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func announceBackIsSkippedWhenAlreadyMarked() throws {
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let now = Date(timeIntervalSince1970: 1_000)
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@@ -316,6 +316,108 @@ struct MessageRouterTests {
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#expect(couriers.contains(favorite))
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}
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/// Residual gap after the rotation-heal containment: a replayed "direct"
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/// announce (TTL is unsigned) can bind an absent victim's peer ID to the
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/// replayer's link, leaving the victim "connected" on a link whose Noise
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/// handshake can never complete. The connected fast-path must not trust
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/// that outright: the send still goes out (a genuine link finishes the
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/// handshake), but a copy is retained and a sealed copy goes to couriers
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/// so nothing is silently lost.
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@Test @MainActor
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func sendPrivate_connectedWithoutSecureSessionRetainsAndDepositsWithCourier() async {
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let victim = PeerID(str: "00000000000000aa")
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let victimKey = Data(repeating: 0xBB, count: 32)
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let courier = PeerID(str: "00000000000000cc")
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let courierKey = Data(repeating: 0xCC, count: 32)
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let transport = MockTransport()
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transport.connectedPeers.insert(victim)
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transport.connectedPeers.insert(courier)
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transport.securePeers = [] // no established Noise session with anyone
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transport.updatePeerSnapshots([Self.snapshot(courier, key: courierKey, verified: true)])
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let router = MessageRouter(
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transports: [transport],
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courierDirectory: Self.directory(recipient: victim, recipientKey: victimKey)
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)
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router.sendPrivate("Hello", to: victim, recipientNickname: "Peer", messageID: "cs1")
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// The send is still attempted (it kicks the handshake on a genuine
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// link) but not trusted outright: a courier gets a sealed copy now …
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#expect(transport.sentPrivateMessages.map(\.messageID) == ["cs1"])
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#expect(transport.sentCourierMessages.count == 1)
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#expect(transport.sentCourierMessages.first?.messageID == "cs1")
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#expect(transport.sentCourierMessages.first?.recipientNoiseKey == victimKey)
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#expect(transport.sentCourierMessages.first?.couriers == [courier])
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// … and the retained copy keeps flushing until a delivery ack — a
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// flush over the insecure link must resend without dropping it.
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router.flushOutbox(for: victim)
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router.flushOutbox(for: victim)
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#expect(transport.sentPrivateMessages.count == 3)
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router.markDelivered("cs1")
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router.flushOutbox(for: victim)
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#expect(transport.sentPrivateMessages.count == 3)
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}
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/// Flushes over a connected-but-insecure link never count toward the
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/// attempt-cap drop: the message was actually transmitted over a live
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/// link, so a peer whose Noise handshake stalls across reconnect flapping
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/// must not burn through the cap and lose the store-and-forward copy the
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/// secure-session gate exists to preserve. Retention stays bounded by
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/// the 24h outbox TTL and the per-peer FIFO cap; an ack clears it.
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@Test @MainActor
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func flushOutbox_connectedInsecureFlushesNeverDropTheRetainedCopy() async {
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let peerID = PeerID(str: "00000000000000ac")
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let transport = MockTransport()
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transport.connectedPeers.insert(peerID)
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transport.securePeers = [] // handshake never completes
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let router = MessageRouter(transports: [transport])
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var dropped: [String] = []
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router.onMessageDropped = { messageID, _ in dropped.append(messageID) }
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router.sendPrivate("Hello", to: peerID, recipientNickname: "Peer", messageID: "ci1")
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// Well past maxSendAttempts (8): every flush resends, none drops.
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for _ in 0..<10 {
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router.flushOutbox(for: peerID)
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}
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#expect(dropped.isEmpty)
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#expect(transport.sentPrivateMessages.count == 11)
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// The copy is still retained and an ack still clears it.
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router.markDelivered("ci1")
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router.flushOutbox(for: peerID)
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#expect(transport.sentPrivateMessages.count == 11)
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}
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/// With an established secure session the connected fast-path stays
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/// exactly as before: trusted outright, no retained copy, no courier.
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@Test @MainActor
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func sendPrivate_connectedWithSecureSessionIsTrustedOutright() async {
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let peerID = PeerID(str: "00000000000000ab")
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let peerKey = Data(repeating: 0xAB, count: 32)
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let courier = PeerID(str: "00000000000000cc")
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let transport = MockTransport()
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transport.connectedPeers.insert(peerID)
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transport.connectedPeers.insert(courier)
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transport.securePeers = [peerID]
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transport.updatePeerSnapshots([Self.snapshot(courier, key: Data(repeating: 0xCC, count: 32), verified: true)])
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let router = MessageRouter(
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transports: [transport],
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courierDirectory: Self.directory(recipient: peerID, recipientKey: peerKey)
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)
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router.sendPrivate("Hello", to: peerID, recipientNickname: "Peer", messageID: "cs2")
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#expect(transport.sentPrivateMessages.map(\.messageID) == ["cs2"])
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#expect(transport.sentCourierMessages.isEmpty)
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router.flushOutbox(for: peerID)
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#expect(transport.sentPrivateMessages.count == 1)
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}
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@Test @MainActor
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func courierBecameAvailable_retriesDepositOnceWithoutDoubleBurn() async {
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let recipient = PeerID(str: "00000000000000aa")
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