k_card/Workplan.md

Workplan

Last updated: 2026-05-08

This is the execution plan for making ChromeCard FIDO2 development and validation reproducible on this machine.

Constraints

• Treat /home/user/chromecard/CR_SDK_CK-main as read-only.
• Keep helper scripts such as fido2_probe.py and webauthn_local_demo.py at /home/user/chromecard.
• Target deployment model is Qubes OS with 3 AppVMs based on debian-13-xfce: k_client, k_proxy, k_server.
• Current authenticator link is card->k_proxy (USB), but architecture must allow migration to wireless phone-mediated validation.
• VM execution path is SSH-first for experiments: ssh <host> <cmd> and scp <file> <host>:~.

Goals

• Re-establish deterministic host-to-card FIDO2 communication over USB HID/CTAPHID.
• Restore a buildable/flashable firmware workspace for CR_SDK_CK-main.
• Turn ad-hoc demos into a repeatable verification flow.
• Stand up chained TLS communication in Qubes: k_client -> k_proxy -> k_server.
• Support both login flow (browser in k_client) and user enrollment flow (process in k_client).
• Minimize repeated card prompts by introducing secure session reuse after successful authentication.
• Implement a protected dummy resource on k_server (monotonic counter) for end-to-end validation.
• Ensure k_proxy and k_server are thread-safe and support concurrent access.
• Prepare k_proxy auth path for future transport shift: USB-direct -> wireless phone bridge.

Phase 0: Qubes VM Baseline (Blocking)

1. Provision/verify AppVMs.

• Ensure k_client, k_proxy, k_server exist and are based on debian-13-xfce.

2. Assign functional responsibilities.

• k_client: browser client + enrollment process.
• k_proxy: USB card access + proxy/auth bridge.
• k_server: protected resource/service endpoint.

3. Define TLS endpoints and certificates.

• k_proxy presents TLS service to k_client.
• k_server presents TLS service to k_proxy.
• Trust roots and cert distribution model documented per VM.

Exit criteria:

• All 3 VMs exist, boot, and have clearly defined service ownership.

Phase 1: Qubes Firewall Policy

1. Enforce allowed forward paths only.

• Allow k_client outbound TLS only to k_proxy service port(s).
• Allow k_proxy outbound TLS only to k_server service port(s).
• Deny direct k_client to k_server traffic.

2. Validate return path behavior.

• Confirm responses propagate back through established flows.

3. Verify with simple probes.

• TLS handshake and HTTP(S) checks from k_client to k_proxy.
• TLS handshake and HTTP(S) checks from k_proxy to k_server.

Exit criteria:

• Policy matches intended chain and is test-verified.

Status (2026-04-24, remote diagnostics):

• Confirmed active blocker remains Phase 1 network policy/pathing.
• Evidence from live VM probes:
  • k_client (10.137.0.16) -> k_proxy (10.137.0.12:8771): TCP timeout.
  • k_proxy (10.137.0.12) -> k_server (10.137.0.13:8780): upstream timeout.
• Local service health inside each VM is good, so failure is inter-VM reachability, not local process startup.

Status (2026-04-25, after restart and service recovery):

• Refined blocker: this is currently a qrexec/qubes.ConnectTCP refusal problem, not an app-local listener problem.
• Current evidence:
  • k_proxy local /health is up on 127.0.0.1:8771
  • k_server local /health is up on 127.0.0.1:8780
  • qrexec-client-vm k_proxy qubes.ConnectTCP+8771 -> Request refused
  • qrexec-client-vm k_server qubes.ConnectTCP+8780 -> Request refused
• Immediate next action for Phase 1:
  • verify and fix the dom0 policy/mechanism that should permit qubes.ConnectTCP forwarding for the chain ports

Status (2026-04-25, dom0 policy fix validated):

• The forwarding blocker is cleared for the current prototype shape.
• Verified working chain:
  • k_client localhost 9771 -> k_proxy:8771
  • k_proxy localhost 9780 -> k_server:8780
• Verified outcome:
  • TLS health checks pass on both hops
  • end-to-end login, session status, protected counter access, and logout all succeed from k_client
• Phase 1 is complete for the current localhost-forwarded qubes.ConnectTCP design.

Phase 2: TLS Certificates and Service Endpoints

1. Certificate model.

• Create or import CA and issue certs for k_proxy and k_server.
• Install trust roots in client VM(s) that need validation.

2. Service shape.

• k_server: HTTPS service exposing protected resource endpoint(s), including a monotonic counter endpoint.
• k_proxy: minimal HTTPS API gateway service (full web server framework not required).

3. Endpoint contract.

• Define request/response schema between k_client and k_proxy.
• Define upstream request contract from k_proxy to k_server.

Exit criteria:

• Mutual TLS trust decisions are documented and tested.
• HTTPS calls succeed on both links with expected cert validation.

Status (2026-04-25):

• Implemented HTTPS listeners in both prototype services.
• Added local CA + service certificate generation in generate_phase2_certs.py.
• Verified the working Qubes path is localhost forwarding plus TLS:
  • k_client local 9771 forwards to k_proxy:8771
  • k_proxy local 9780 forwards to k_server:8780
• Verified cert validation on both hops using the generated CA.
• Verified end-to-end HTTPS flow:
  • k_client -> k_proxy login over TLS
  • k_proxy -> k_server protected counter call over TLS
  • session reuse still works across repeated protected requests
• Phase 2 is now effectively complete for the current prototype shape.

Phase 2.5: Define State Ownership and Concurrency Model

1. State ownership.

• Decide where user/session state is authoritative (k_proxy, k_server, or split model).
• Define token/session format and validation boundary.

2. Concurrency controls.

• Define thread-safe strategy for session store and shared counters.
• Define locking/atomic/update semantics for counter increments and session updates.

3. Runtime model.

• Choose service runtime/config that supports simultaneous requests safely.

Exit criteria:

• Architecture clearly documents state authority and race-free update rules.

Next action (2026-04-25):

• Move into Phase 2.5 and make the current prototype decisions explicit:
  • authority for session state remains k_proxy
  • k_server remains authority for the protected counter/resource state
  • localhost Qubes forwarders are part of the active runtime model for the two TLS hops
  • define concurrency assumptions and limits around session store, forwarders, and counter access

Status (2026-04-25):

• Current ownership model is now explicit:
  • k_proxy is authoritative for session creation, expiry, lookup, and logout
  • k_server is authoritative for the protected monotonic counter
  • k_client is a client only; it holds bearer tokens but is not a state authority
• Current validation boundary is explicit:
  • k_proxy validates bearer tokens against its in-memory session store
  • k_server trusts only requests that arrive with the configured X-Proxy-Token
  • k_server does not currently validate end-user session tokens directly
• Current concurrency strategy is explicit:
  • k_proxy uses ThreadingHTTPServer plus one lock around the in-memory session map
  • k_server uses ThreadingHTTPServer plus one lock around counter increments
  • upstream HTTPS calls from k_proxy are made outside the session-store lock
• Current runtime limits are explicit:
  • sessions are process-local and disappear on k_proxy restart
  • counter state is process-local and resets on k_server restart
  • transport relies on Qubes localhost forwarders 9771 and 9780
• Phase 2.5 is complete for the current prototype shape.

Phase 3: Recover Basic Device Visibility on k_proxy (Blocking)

1. Verify physical + USB enumeration path.

• Check cable/port and confirm device appears in USB listings.
• Confirm /dev/hidraw* nodes appear when card is connected.

2. Validate Linux permissions.

• Install/update udev rule for ChromeCard HID VID/PID.
• Reload udev and verify non-root read/write access to hidraw node.

3. Re-run host probe.

• Run python3 /home/user/chromecard/fido2_probe.py --list.
• Run python3 /home/user/chromecard/fido2_probe.py --json.
• Record VID/PID/path and CTAP2 getInfo output in Setup.md.

Exit criteria:

• At least one CTAP HID device is listed.
• --json returns valid ctap2_info.

Phase 4: Re-validate Local WebAuthn Demo on k_proxy

1. Start local demo server.

• Run python3 /home/user/chromecard/webauthn_local_demo.py.
• Confirm URL is http://localhost:8765.

2. Exercise register/login.

• Register a test user.
• Authenticate with same user.
• Capture errors (if any) and update Setup.md.

3. Decide next demo hardening step.

• Keep bring-up-only mode, or
• add signature verification for attestation/assertion.

Exit criteria:

• Register and login both complete with card interaction prompts.

Status (2026-04-24):

• Completed in k_proxy using http://localhost:8765.
• Registration result: ok=true, username=alice, credential_count=1.
• Authentication result: ok=true, username=alice, authenticated=true.

Phase 5: Implement Proxy Auth + Session Reuse

1. Authenticate via card once per session window.

• k_proxy handles initial auth using connected card.
• On success, create session state for k_client.

2. Session model.

• Prefer server-side session store or signed session token.
• Include TTL/expiry, rotation, and explicit invalidation/logout path.
• Do not expose card secrets or long-lived auth material to k_client.

3. Proxying behavior.

• With valid session: k_proxy forwards request to k_server and returns result.
• Without valid session: require fresh card-backed auth flow.

Exit criteria:

• Repeated authorized requests do not require card interaction until session expiry.
• Expired/invalid sessions are correctly rejected.

Status (2026-04-24):

• Started with a runnable prototype:
  • /home/user/chromecard/k_proxy_app.py
  • /home/user/chromecard/k_server_app.py
  • /home/user/chromecard/PHASE5_RUNBOOK.md
• Implemented in prototype:
  • session create/status/logout endpoints in k_proxy
  • TTL-based server-side session store with expiry garbage collection
  • protected monotonic counter endpoint in k_server with thread-safe increments
  • proxy forwarding from k_proxy to k_server using a shared upstream token
• Current auth gate for session creation is card-presence probe (fido2_probe.py --json), pending upgrade to full assertion verification path.

Status (2026-04-25):

• Prototype services were re-started successfully after VM restart.
• Current split-VM test shape is:
  • k_proxy listening on 127.0.0.1:8771
  • k_server listening on 127.0.0.1:8780
• End-to-end validation is now passing through the live chain from k_client.
• Current verified behavior:
  • login succeeds for alice
  • session status succeeds
  • repeated protected counter requests succeed with session reuse
  • logout succeeds
  • post-logout protected access returns 401
• Added repeatable host-side regression helper:
  • /home/user/chromecard/phase5_chain_regression.sh
• Phase 5 is complete for the current prototype semantics.
• Experimental follow-up in code:
  • k_proxy_app.py now also has --auth-mode fido2-direct
  • this mode attempts direct credential registration and direct assertion verification with python-fido2
  • it is not the deployed default because direct registration currently fails on k_proxy with No compatible PIN/UV protocols supported!
  • /home/user/chromecard/raw_ctap_probe.py now exists for lower-level CTAP2 probing with keepalive/error logging
  • latest retry result: after reattaching the card, k_proxy again exposes /dev/hidraw0 and /dev/hidraw1, but raw makeCredential still reaches no Yes/No card prompt
  • /dev/hidraw0 opens successfully as the normal user; /dev/hidraw1 is still permission-denied
  • manual CTAPHID testing now shows /dev/hidraw0 is the correct FIDO interface and a direct INIT write gets no response at all
  • rerunning webauthn_local_demo.py inside k_proxy also still gives no card prompt, so the current break is below both browser WebAuthn and direct host probes
  • after a full power cycle and reattach, manual CTAPHID INIT replies again and browser registration in webauthn_local_demo.py succeeds again
  • direct raw_ctap_probe.py --device-path /dev/hidraw0 make-credential --rp-id localhost now also succeeds again after card confirmation
  • k_proxy_app.py --auth-mode fido2-direct has been moved onto low-level CTAP2 with hidraw auto-detection; it still accepts --direct-device-path, but no longer breaks if the card re-enumerates onto /dev/hidraw1
  • after repeated fixes for hidraw lifetime, VM-side python-fido2 response mapping, and CTAP payload shape, real app registration now succeeds for directtest

Phase 5.5: Implement Dummy Resource + Access Policy on k_server

1. Protected dummy resource.

• Add endpoint returning increasing number.
• Require valid upstream auth/session context from k_proxy.

2. Optional user/session handling.

• Add minimal user/session checks if k_server is chosen as authority (or partial authority).

3. Correctness under concurrency.

• Ensure increments are monotonic and race-safe under parallel calls.

Exit criteria:

• Authorized requests obtain consistent increasing values.
• Unauthorized requests are rejected.

Status (2026-04-25):

• The protected counter resource is implemented and validated in the live split-VM chain.
• Verified behavior:
  • authorized requests from k_proxy obtain increasing values
  • unauthorized post-logout requests from k_client are rejected with 401
  • 20 concurrent protected requests through the chain returned unique, gap-free values
• Phase 5.5 is complete for the current prototype shape.

Phase 6: Integrate Client Enrollment + Proxy Login Flow

1. Enrollment process in k_client.

• Start process from k_client that captures new-user enrollment intent/data.
• Route enrollment requests to k_proxy over TLS.

2. Card-mediated login in k_proxy.

• k_proxy uses connected card for FIDO2/WebAuthn operations.
• k_proxy authenticates toward k_server over TLS.

3. Browser flow in k_client.

• Browser traffic goes only to k_proxy.

Immediate next action:

• Preserve the now-working direct auth path as a tested option while keeping the default deployed baseline stable.
• Verified end-to-end state:
  • direct /enroll/register succeeds for directtest
  • direct /session/login succeeds for directtest
  • /session/status succeeds
  • protected /resource/counter succeeds through k_proxy -> k_server
  • /session/logout succeeds
  • post-logout protected access returns 401
• Next work should be cleanup/hardening:
  • decide whether to keep directtest enrollment
  • rerun phase5_chain_regression.sh --interactive-card --expect-auth-mode fido2_assertion against the current direct-auth baseline
  • decide when fido2-direct should replace probe as the default deployed auth mode

Exit criteria:

• Enrollment and login both function end-to-end via k_client -> k_proxy -> k_server.

Status (2026-04-25):

• Added first k_client implementation at /home/user/chromecard/k_client_portal.py.
• Current prototype flow:
  • browser now targets k_proxy directly over https://127.0.0.1:9771
  • k_client_portal.py also serves a local browser flow page on http://127.0.0.1:8766
  • k_proxy continues to authenticate with the card and forward to k_server
  • the k_client page now also lists registered users from k_proxy
  • the k_client page can unregister users from the browser
  • the portal login action now uses the current username field instead of only the remembered local user
  • a Playwright regression spec now exists for the browser flow in tests/k_client_portal.spec.js
  • the Playwright browser regression has now passed end-to-end once from this host against a forwarded portal URL
• Verified end-to-end through the portal:
  • enroll alice
  • login succeeds
  • session status succeeds
  • protected counter succeeds repeatedly with session reuse
  • logout succeeds
• Enrollment contract progress:
  • k_proxy now exposes prototype enrollment endpoints
  • proxy-side enrollment storage exists and is checked before login is allowed
  • direct browser/API traffic can now use those proxy endpoints without going through the local bridge
• Phase 6 is materially further along for the current prototype shape:
  • direct browser target is on k_proxy
  • login/resource flow is integrated on the direct proxy path
  • enrollment now has a real client->proxy path
  • the k_client page is now a usable demo/operator surface in addition to the direct proxy path
  • final enrollment semantics are still provisional

Status (2026-04-25, enrollment hardening):

• Added a more explicit provisional enrollment contract in k_proxy:
  • username normalization and validation
  • optional display_name
  • separate create, update, delete, status, and list operations
  • delete invalidates existing sessions for that username
• Verified the hardened behaviors on the direct proxy path.
• Phase 6 is now strong enough to treat the browser/proxy flow as a stable prototype baseline.
• The remaining reason Phase 6 is not "final" is product semantics, not missing basic mechanics:
  • whether enrollment should require card presence
  • what user attributes belong in enrollment
  • what re-enroll and recovery should mean

Status (2026-04-25, Phase 6.5 initial concurrency results):

• Added reproducible probe script at /home/user/chromecard/phase65_concurrency_probe.py.
• Probe now supports --max-workers so client-side fan-out can be tested separately from total request count.
• Moderate direct-path concurrency passes:
  • 3 users x 4 requests
  • 12/12 successful protected calls
  • counter values remained unique and contiguous
• Larger direct-path concurrency currently fails:
  • 5 users x 5 requests
  • only 18/25 successful protected calls
  • failed calls report TLS EOF / upstream unavailable errors
• Follow-up findings are more precise:
  • body-drain handling was fixed for the HTTP/1.1 keep-alive experiment
  • k_proxy -> k_server upstream concurrency is now clampable and currently tested at one pooled connection
  • 5 users x 5 requests passes at 25/25 when client fan-out is limited to --max-workers 10
  • the same total load still fails at higher fan-out:
    • 22/25 at --max-workers 15
    • 15/25 at fully unbounded 25 workers in the latest rerun
• Current bottleneck is still not counter correctness:
  • successful results still show unique, contiguous counter values
  • k_proxy and k_server complete the requests that actually arrive
• Current likely bottleneck is the client-facing Qubes forwarding layer:
  • qvm_connect_9771.log shows qrexec data-vchan failures
  • observed message includes xs_transaction_start: No space left on device
  • qvm_connect_9780.log showed earlier failures too, but the latest threshold test points first to connection fan-out on k_client -> k_proxy
• Phase 6.5 is therefore started but not complete:
  • application-level concurrency looks acceptable at moderate load
  • current working envelope is roughly 10 in-flight protected calls on the direct browser path
  • higher-load failures still need Qubes forwarding diagnosis before the phase can be closed

Status (2026-04-25, Phase 5 regression helper):

• Added repeatable split-VM regression helper:
  • /home/user/chromecard/phase5_chain_regression.sh
• Verified helper result on the live chain:
  • 20 requests at parallelism 8
  • login/session-status/counter/logout sequence completed successfully
  • returned counter values were unique and gap-free
  • latest verified helper range was 43..62
• Current implication:
  • the Phase 5 baseline is now reproducible
  • next work should target auth semantics rather than basic chain bring-up

Phase 6.5: Concurrency and Multi-Client Test Setup

1. Single-VM concurrency tests.

• Generate parallel request bursts from k_client to k_proxy.
• Verify response integrity, session reuse behavior, and error rates.

2. Multi-client tests.

• Run requests from multiple k_client instances (or equivalent parallel clients) concurrently.
• Verify isolation between users/sessions.

3. Acceptance checks.

• No race-related crashes/corruption in k_proxy or k_server.
• Counter/resource behavior remains correct under load.
• Session reuse reduces card prompts while preserving authorization checks.

Exit criteria:

• Test results demonstrate stable concurrent operation with documented limits.

Phase 7: Restore Firmware Build/Flash Path

1. Validate SDK tree completeness.

• Confirm presence of mvp, setup, components, samples under CR_SDK_CK-main.
• If missing, obtain full repository/checkpoint and document source.

2. Install/enable build tools.

• Ensure west and nrfjprog are available in shell.
• Confirm target board/toolchain match (nrf7002dk/nrf5340/cpuapp, NCS v2.9.2 baseline in docs).

3. Run baseline build+flash.

• From CR_SDK_CK-main, run ./scripts/build_flash_mvp.sh.
• If flashing fails, run documented recovery and retry.

Exit criteria:

• Successful west build and west flash.

Phase 8: Consolidate Documentation and Paths

1. Remove path drift between docs and actual files.

• Keep fido2_probe.py and webauthn_local_demo.py at workspace root.
• Ensure docs never instruct placing helper scripts under CR_SDK_CK-main.
• Update references consistently in all docs.

2. Keep Setup.md current.

• After each significant change, update status snapshot and outcomes.

3. Add minimal reproducibility checklist.

• One command list for probe + demo + build/flash prechecks.

4. Maintain Markdown execution records continuously.

• Setup.md and Workplan.md are the canonical living docs for this workspace.
• Re-scan relevant .md files before each new execution cycle and reconcile drift.
• Record date-stamped session notes when priorities or blockers change.

Status (2026-04-24, markdown maintenance):

• Re-scanned the active workspace Markdown set and the main source-tree reference docs.
• No workplan phase change was required from this pass.
• Ongoing documentation watch item remains path drift in CR_SDK_CK-main/README_HOST.md, which still uses historical ./scripts/... helper locations instead of workspace-root helper paths.
• Operational note: the markdown scan path now runs cleanly after policy adjustment when invoked without a login shell.

Status (2026-04-24, chain probe retry):

• Phase 1 remains blocked, but the failure point is now narrowed further:
  • current refusal occurs at Qubes qubes.ConnectTCP policy/service evaluation for ports 22, 8770, and 8780
  • this happens before any end-to-end app-level request can be retried
• Practical implication:
  • do not spend time on k_proxy_app.py / k_server_app.py request handling until qrexec forwarding is permitting the intended hops again
  • next recovery action is to fix/activate the relevant Qubes qubes.ConnectTCP policy and then re-run the qrexec bridge checks before testing HTTP flow

Status (2026-04-25, post-restart probe):

• Corrected the client-facing proxy port reference to 8771.
• SSH access to k_proxy and card visibility recovered after VM restart.
• New immediate blockers are:
  • k_proxy service not listening on 127.0.0.1:8771
  • k_server service not listening on 127.0.0.1:8780
  • qrexec forwarding for 8771 and 8780 still returns Request refused
• Next retry should start services first, then re-test qrexec forwarding and only then attempt end-to-end client flow.

Status (2026-04-25, service restart):

• Local VM services are running again on the intended loopback ports:
  • k_server: 127.0.0.1:8780
  • k_proxy: 127.0.0.1:8771
• Phase 1 remains blocked specifically by qrexec policy/forwarding refusal on those ports.
• Next action is no longer app startup; it is fixing the qubes.ConnectTCP allow path for 8771 and 8780.

Status (2026-04-25, in-VM forwarding test):

• Verified that using qvm-connect-tcp inside the source VMs still does not complete the client->proxy hop:
  • bind succeeds locally, but first real connection gets Request refused
• Independent app-layer blocker also found in k_proxy:
  • python-fido2 is missing there, so local /session/login currently fails before card auth can succeed
• Current ordered blockers:
  • first: effective Qubes/qrexec allow path for k_client -> k_proxy:8771
  • second: install python-fido2 in k_proxy
  • third: re-test end-to-end login and then proxy->server counter flow

Status (2026-04-25, after python3-fido2 install):

• python3-fido2 blocker in k_proxy is resolved.
• Updated ordered blockers:
  • first: effective Qubes/qrexec allow path for k_client -> k_proxy:8771
  • second: restore CTAP HID device visibility/access in k_proxy (No CTAP HID devices found)
  • third: re-test end-to-end login and then proxy->server counter flow

Status (2026-04-25, card reattached):

• CTAP HID visibility/access in k_proxy is restored.
• Local proxy login is working again with the attached card.
• The only currently confirmed blocker for the end-to-end path is the k_client -> k_proxy:8771 qrexec/qvm-connect-tcp refusal.

Status (2026-04-25, clean forward retest):

• The retest shows the same qrexec failure mode on both hops, not just the client-facing one.
• Updated blocker statement:
  • effective qubes.ConnectTCP allow path is failing for both
    • k_client -> k_proxy:8771
    • k_proxy -> k_server:8780
• App services and card path are currently good; forwarding remains the single active system blocker.

Status (2026-04-25, dom0 policy fix validated):

• The explicit-destination dom0 qubes.ConnectTCP policy fix resolved forwarding on both hops.
• Current verified working chain:
  • k_client -> k_proxy:8771
  • k_proxy -> k_server:8780
• Current verified prototype behavior:
  • session login works from k_client
  • session status works
  • protected counter flow reaches k_server
  • session reuse avoids re-login for repeated counter calls
  • logout invalidates the session and subsequent protected access returns 401
• Immediate networking blocker is cleared.

Exit criteria:

• New team member can follow docs end-to-end without path or tooling ambiguity.

Phase 9: Migrate to Phone-Mediated Wireless Validation

Status (2026-05-04): ACTIVE — Architecture v2 adopted; Component 1 + Component 2 CONNECT handler complete

Architecture v2 changes (2026-05-04)

The following changes replace the v1 architecture. Source: chromecard_arkitektur_v2.docx.

Component 2 no longer calls endpoints: Component 2 returns the WebAuthn token to whoever asked (Component 1). It is Component 1 that calls the endpoint with the token. This is the most important behavioral change.

New Component 3 (external client): A compiled binary (Go recommended, Rust alternative) installed on external client computers. Replaces the old browser-proxy-configuration approach. Tasks: find the phone (currently hardcoded IP+port — rendezvous TBD), forward validation requests to Component 1, receive token back, call the protected endpoint directly, return response to browser.

Flow A splits into two paths:

• Phone browser: Browser → Component 1 → Component 2 (returns token) → Component 1 calls endpoint → resource
• External client: Browser → Component 3 → Component 1 → Component 2 (returns token) → Component 1 → Component 3 calls endpoint → resource

Platform note: Android needs no extra infrastructure. iOS requires a push-relay (APNs) for background operation — platform priority is an open decision.

New open decisions: Rendezvous mechanism for Component 3; iOS vs Android priority.

Architectural decision (2026-05-08) — token binding model: Current choice: per-request authentication. No session is opened. Each request to a gated resource requires a fresh FIDO2 assertion from the card, with the challenge bound to the specific request (URL + method + nonce). The server verifies that the assertion's challenge matches the resource being requested. A token cannot be replayed for a different resource. Consequence: one card interaction per request. This is intentional for now. May change to: session model (one card interaction opens a time-limited session for all gated resources). If changed, token must at minimum be bound to a specific server (audience) to prevent cross-server replay. Trigger for revisiting: user experience — if per-request card interaction proves too slow or disruptive.

Target architecture (v2)

Four physical devices: optional client computer, phone, chromecard, server.

Phone components:

• Component 1 — Proxy + gating filter: Receives requests from phone browser and from external clients via Component 3. Per-request: gated host → forward to Component 2, receive WebAuthn token back, call endpoint with token (TLS); non-gated → forward directly to internet on port 80 (no TLS, bypasses auth entirely).
• Component 2 — WebAuthn client + URL recognition: Always returns token to caller, never calls endpoints itself. Detects registration URL → admin registration flow (admin fingerprint); other gated URLs → FIDO2 assertion flow (user fingerprint → token returned to Component 1).
• Registration page: Local web app on phone; admin fingerprint access control enforced by card.
• Component 3 (external client): Compiled binary, finds phone, relays auth through Component 1, calls endpoint with received token.

Three flows:

• Flow A (phone browser): Browser → Comp 1 → Comp 2 → card → token → Comp 1 → endpoint → resource
• Flow A (external client): Browser → Comp 3 → Comp 1 → Comp 2 → card → token → Comp 1 → Comp 3 → endpoint → resource
• Flow B: Browser → Comp 1 → Comp 2 (registration URL) → card (admin biometric) → enroll/delete user
• Flow C: Non-gated host → Comp 1 → internet port 80 (no TLS, no card)

Open decisions: PIN on card; user DB on-card vs. external; network-level access control on registration page; Component 3 rendezvous mechanism; iOS vs Android priority.

Development chain (Qubes): k_client browser → k_phone (Flutter Android) → USB HID → ChromeCard → k_server

The k_phone Flutter app replaces k_proxy entirely. It presents the same HTTP API as k_proxy_app.py so k_client_portal.py and the browser portal work without changes.

Development environment: Mac (not Qubes). Android emulator is incompatible with Xen/Qubes. All k_phone development and testing runs on the Mac with the Android emulator and card_emulator_bridge.py.

Work completed (2026-04-29)

• Flutter project scaffolded at k_phone/ (no flutter create — fully hand-written)
• 10+ Android build issues resolved (AGP, Gradle, Kotlin, desugaring, notification channel, foreground service type)
• k_phone/lib/ctaphid_channel.dart: full CTAPHID framing + USB/emulator dual-transport
  • Fixed: persistent socket subscription (single-subscription stream cannot use await for ... break per packet)
  • Fixed: _emulatorSocketOpen flag prevents dead-socket writes from raising StateError
  • Fixed: emulator round-trip sends all request packets before reading (no per-packet blocking)
• k_phone/lib/proxy_service.dart: full HTTP proxy — all endpoints implemented, error handling hardened
  • Fixed: card-error try-catch separated from DB StateError catch (was masking socket errors as "user already enrolled")
  • autoStart: true for emulator testing; revert to false for production builds
• k_phone/lib/enrollment_db.dart: enrollment model + JSON persistence via path_provider
• k_phone/lib/fido2_ops.dart: CTAP2 makeCredential, getAssertion, ECDSA-P256 assertion verification
  • Fixed: CTAP2 command prefix bytes (0x01/0x02) prepended to CBOR payload per CTAP2-over-CTAPHID spec
• k_phone/lib/session_manager.dart: in-memory bearer token sessions; hasAnyActiveSession() added for gated-proxy forwarding (personal-device model: any live session authorises gated traffic)
• k_phone/lib/k_server_client.dart: HTTP forwarder to k_server
• k_phone/android/app/src/main/kotlin/.../MainActivity.kt: USB HID Kotlin platform channel
• tests/card_emulator_bridge.py: asyncio CTAPHID TCP bridge wrapping CardEmulator for emulator dev

Work completed (2026-05-02)

• k_phone/lib/filter_proxy.dart: Component 1 implemented — HTTP proxy with gating filter
  • Plain HTTP to gated host: rewritten to relative path and forwarded to Component 2
  • HTTPS CONNECT to gated host: CONNECT request relayed to Component 2; tunnel opened on 200, denied on 4xx
  • All other traffic forwarded directly to target host
  • Gated hosts file: gated_hosts.txt in app documents directory (one host or host:port per line)
  • Default seeded with httpbin.org on first run
• k_phone/test/filter_proxy_test.dart: full test suite for Component 1 (gated matching, HTTP routing, CONNECT routing, edge cases)
• k_phone/test/enrollment_test.dart: full test suite for EnrollmentDb (register, list, delete, persistence, update)

Work completed (2026-05-02, session 2)

• k_phone/lib/proxy_service.dart: _handleConnect added to _ProxyServer
  • Dispatched from _handleRequest for CONNECT method
  • Checks _sessions.hasAnyActiveSession() — returns 407 if no active session
  • Extracts upstream host:port from Host header
  • Opens TCP socket to upstream target (the real external server — httpbin.org, etc.)
  • Detaches the HTTP socket (detachSocket(writeHeaders: false)) and writes 200 Connection Established manually
  • Pipes bytes bidirectionally: client ↔ upstream
  • k_server is not involved in CONNECT tunnels; Component 2 connects directly to the real target

Verified on emulator (2026-04-29)

POST /enroll/register  → makeCredential via bridge → has_credential: true  ✓
POST /session/login    → getAssertion + ECDSA verify → auth_mode: fido2_assertion  ✓
POST /session/status   → 299 s remaining  ✓
POST /session/logout   → invalidated: true  ✓
POST /resource/counter → internal error (k_server not running locally — expected)
POST /resource/counter (after logout) → 401 invalid or expired session  ✓

Bridge log confirmed:

CTAP2 cmd=0x01 body=180 bytes → makeCredential OK auth_data=164 bytes
CTAP2 cmd=0x02 body=113 bytes → getAssertion OK auth_data=37 bytes sig=71 bytes

Work completed (2026-05-05, v2 architecture refactor)

k_phone (Dart):

• filter_proxy_test.dart: rewritten for v2 semantics — gated HTTP now hits a mock endpoint with Bearer token, not Component 2 directly. 24/24 tests pass.
• filter_proxy.dart: extracted _writeProxyHeaders and _forwardHttpRequest helpers to eliminate ~30 lines of duplication between _handleGatedHttp and _handleDirectHttp; simplified _handleDirectHttp signature (redundant host/port params removed).
• session_manager.dart: added static const int ttlSeconds = 300 (public); _ttl now references it.
• portal_html.dart (new): extracted 400-line HTML blobs (kPortalHtml, kEnrollHtml, kPortalHtmlBytes, kEnrollHtmlBytes) from proxy_service.dart.
• proxy_service.dart: imports portal_html.dart; removed _kSessionTtlSeconds constant (replaced with SessionManager.ttlSeconds); merged _serveHtml/_serveEnrollHtml into _serveHtmlBytes(req, bytes); extracted _parseUsername and _parseUsernameAndDisplay helpers eliminating repeated validation boilerplate; removed dead _loadTlsContext stub; simplified start() TLS branch. File: 872 → 455 lines.
• k_server_client.dart: deleted (dead code — no longer imported anywhere).

component3 (Go):

• gated.go: IsGated(host, port string) — was IsGated(host string). Was silently missing host:port entries in gated_hosts.txt. Now checks both bare hostname and host:port.
• proxy.go: handleHTTP extracts port from URL (defaults "80"), passes to IsGated; handleConnect passes portStr to IsGated.
• phone.go: added getToken() calling /auth/get-token — avoids FIDO2 card interaction if the phone already has an active session. EnsureSession() tries getToken() first, falls back to login(). Fixed login() JSON field: expires_in → ttl_seconds (actual server field name). go build ./... passes.

Parallel-change note: Component 1 and Component 3 share the same proxy logic

Component 3 (component3/) and Component 1 (k_phone/lib/filter_proxy.dart) implement the same core behaviour: intercept HTTP/HTTPS traffic, decide per-request whether the target is gated, fetch a WebAuthn token if so, and call the endpoint directly with the token. Any structural change to one (new gating logic, token-binding changes, CONNECT handling, error semantics) will almost certainly need a corresponding change in the other. Treat them as a pair: when modifying Component 3, check Component 1 for the same fix, and vice versa.

Work completed (2026-05-08, per-request token binding)

• fido2_ops.dart: GetAssertionResult now includes clientDataJson; getAssertion() accepts optional challenge param for binding.
• proxy_service.dart: _handleAuthGetToken rewritten — accepts {url, method, nonce}, derives challenge = SHA256(url|method|nonce), calls card (getAssertion), returns self-contained assertion bundle as base64url Bearer token. No session involved.
• filter_proxy.dart: _getAuthToken(uri, method) generates a secure 16-byte nonce, posts {url, method, nonce} to Component 2, uses returned assertion token directly.
• component3/phone.go: rewritten as stateless GetTokenForRequest(url, method) — no session caching, no mutex, no expiry tracking.
• component3/proxy.go: handleHTTP uses GetTokenForRequest(r.URL.String(), r.Method).
• component3/main.go: --user flag removed (Component 2 picks the enrolled user).
• k_server_app.py: _verify_assertion_token() added — decodes bundle, verifies path+method match, verifies challenge claim, verifies ECDSA-P256 signature over authData||clientDataHash using public key extracted from bundle's credentialData. _is_proxy_authorized() accepts either X-Proxy-Token (legacy k_proxy path) or Bearer assertion token.
• filter_proxy_test.dart: 2 new tests for /auth/get-token body fields (url, method, nonce). 48/48 tests pass.
• tests/test_k_server.py: 17 Python tests for _verify_assertion_token — 12 unit tests with synthetic P-256 keys, 5 round-trip tests via CardEmulator. All pass.
• 48/48 Flutter tests pass; go build ./... clean; flutter analyze no issues.

Work completed (2026-05-08, Playwright acceptance tests for k_phone)

• tests/k_phone_portal.spec.js (new): Portal UI acceptance tests (enroll → login → status → list → logout → delete). DOM assertions against #storedUser, #sessionActive, #log. Also tests empty-username and unknown-user error paths.

  • Run: K_PHONE_BASE_URL=http://phone-ip:8771 npx playwright test tests/k_phone_portal.spec.js

• tests/k_phone_proxy.spec.js (new): Proxy routing acceptance tests. Four serial tests that prove Component 1's routing decisions:

  1. No users → non-gated request passes through (< 500).
  2. No users → gated request rejected with 407 (Component 2 has no enrolled user).
  3. Register user (card fingerprint) → non-gated still passes through.
  4. With enrolled user → gated request succeeds after card assertion (200); response body proves Bearer token was forwarded to target.
  • Uses Node http module for proxy requests (absolute URI / proxy protocol).
  • Uses Playwright page fixture for enrollment in test 3 (card interaction).
  • GATED_URL defaults to http://httpbin.org/get; point at http://k-server-ip:8780/resource/counter (GATED_METHOD=POST) for full chain validation including token signature verification.
  • Run: K_PHONE_PROXY=http://phone-ip:8888 K_PHONE_BASE_URL=http://phone-ip:8771 npx playwright test tests/k_phone_proxy.spec.js

Work completed (2026-05-09, Android Playwright tests passing)

• tests/k_phone_android.spec.js: all 4 tests pass (16 s total). Two root causes fixed:

  1. launchBrowser() hangs on Chrome 145. Replaced with: write proxy flag to /data/local/tmp/chrome-command-line, force-stop + restart Chrome, adb forward tcp:9222 localabstract:chrome_devtools_remote, chromium.connectOverCDP(). CDP polling loop handles startup variance (≤ 15 s).

  2. Stale emulator socket after bridge restart. proxy_service.dart: added _ensureCardOpen() — checks isCardAttached() and re-runs _tryOpenCard() if the socket is closed. Called before makeCredential and getAssertion in all three handler paths (enroll, session login, /auth/get-token).

• playwright.config.js: global timeout reduced from 180 s → 60 s.

• adb auto-detected at ~/Library/Android/sdk/platform-tools/adb without PATH changes.

• card_emulator_bridge.py is long-running; no restart needed between test runs.

Next action

1. Deploy to a real Android phone with physical ChromeCard via USB
2. Verify USB HID path (Kotlin MainActivity.kt platform channel, hidraw node auto-detection)
3. Run phase5_chain_regression.sh against k_phone on Android with k_server running

k_phone API contract (must match k_proxy_app.py exactly)

• GET /health
• POST /enroll/register {"username","display_name"}
• GET /enroll/status?username=
• POST /enroll/update {"username","display_name"}
• POST /enroll/delete {"username"}
• GET /enroll/list
• POST /session/login {"username"}
• POST /session/status
• POST /session/logout
• POST /resource/counter (forwarded to k_server with X-Proxy-Token)

Key design decisions

• rp_id: "localhost", origin: "https://localhost" (matches k_proxy_app.py defaults)
• clientDataHash = SHA256(clientDataJSON), where clientDataJSON = {"type":"webauthn.create","challenge":"<b64>","origin":"https://localhost","crossOrigin":false}
• credential_data_b64 stores AttestedCredentialData bytes = aaguid(16) + credIdLen(2) + credId(n) + coseKey
• Signature verification: ECDSA-SHA256(authData || clientDataHash, P-256 pubKey extracted from COSE key)
• No begin/complete HTTP round-trip — registration and auth are each a single HTTP call (same as Python)
• Sessions: server-side in-memory, TTL 300 s (matching Python default), token = 32-byte hex

start bridge for emulator testing

uv run --python 3.12 --with fido2 --with cbor2 --with cryptography tests/card_emulator_bridge.py

Phase 9 exit criteria

• k_phone presents identical HTTP API to k_proxy_app.py (so k_client works unchanged)
• Registration and login both complete via card_emulator_bridge.py in emulator testing
• With physical ChromeCard plugged into Android phone: full register → login → counter → logout works
• phase5_chain_regression.sh passes against k_phone on Android

Current Next Step

Status (2026-04-29):

• Phase 9 emulator milestone complete: makeCredential + getAssertion verified via CardEmulator bridge.
• Next blocking step: deploy to real Android phone with ChromeCard over USB.
• k_server is not running in the Mac test environment; counter endpoint will work once running in Qubes.

Phase status (2026-04-29):

• Phase 6.5 (concurrency): deferred. ~10 in-flight ceiling is acceptable.
• Phase 7 (firmware build/flash): blocked on Chrome Roads (card vendor).
• Phase 9 (phone integration): emulator FIDO2 verified; physical phone + USB HID path is next.

Status (2026-04-26, markdown maintenance):

• Re-scanned Setup.md, Workplan.md, and PHASE5_RUNBOOK.md against the current workspace files.

Inputs Expected During This Session

• Exact observed behavior on reconnect attempts (USB/hidraw/probe).
• Whether we should pull server-side code now.
• Any board/firmware variants different from default documentation assumptions.
• Preferred TLS ports, certificate approach, and hostname scheme for k_client, k_proxy, k_server.
• Session TTL and invalidation requirements for cached authenticated access.
• Decision on where user/session authority lives (k_proxy vs k_server vs split).
• Target concurrency level for validation (parallel clients and parallel requests per client).
• Preferred wireless transport/protocol between k_proxy and phone (for future phase).

Session Maintenance Notes (2026-04-24)

• Top-level Markdown review completed for PHASE5_RUNBOOK.md, Setup.md, and Workplan.md.
• Current execution plan remains in sync with the Phase 5 runbook:
  • prototype services at /home/user/chromecard/k_proxy_app.py and /home/user/chromecard/k_server_app.py
  • run sequence documented in /home/user/chromecard/PHASE5_RUNBOOK.md
• No phase ordering or blocker changes were required from this review pass.
• Remote execution support is now active and validated:
  • ssh command execution works for k_client, k_proxy, k_server
  • scp push to VM home works (validated on k_proxy)