# Web administration contracts

Current, accepted firmware behavior. Phase status and executed-evidence limits belong in the [roadmap](roadmap.md#phase-8--role-based-users-and-administrative-access--complete) and [acceptance record](web_administration_acceptance.md), not in implementation timelines. [Regression procedures](user_administration_tests.md#integrated-web-administration-regression-procedure) describe checks, not results. Source is authoritative; start with the [code map](agent/code-map.md).

## Authentication and admission

- HTTPS-only, same-origin login replaces Basic authentication entirely. Four digest-only opaque sessions have absolute one-hour expiry; four pre-login challenges last 120 seconds. Login is globally bounded to five credential attempts per 60 seconds. Live sessions/challenges/tickets are not evicted to admit another client.
- Raw tokens travel only in the host-only `__Host-` cookie with Secure, HttpOnly, SameSite=Strict, Path=/ and explicit lifetime; no Domain. Session records retain copied secret-free principals, CSRF state and nonzero, nonreused originating-session IDs. Passwords, raw cookies/tickets, verifiers and private keys never enter routine snapshots/logs/completion/display.
- Mutation admission requires current cookie/principal, strict Origin and CSRF validation; administration additionally requires current `admin`. Normal users retain serial/status but cannot invoke administration directly. Authentication POST fetches use CORS mode with fixed same-origin URLs and same-origin credentials: do not accept Origin `null` to compensate for browser no-referrer behavior.
- Session-store initialization is part of admitted HTTPS start; authentication failure gates HTTPS. Failed start/accepted stop disables and wipes session state. Logout invalidates only the originating session before socket cleanup; account mutation invalidates that account's sessions/tickets, including deletion/recreation, without revoking unrelated accounts. Currentness checks remain authoritative if best-effort notifications fail.
- Four serial tickets and two admin tickets are digest-only, single-use, 30-second, session/principal-bound records. Cookie/Origin/ticket/currentness and transport admission precede explicit WebSocket 101. Store RNG/SHA/database calls run outside short spinlocks; IDs/expiry/epochs fence stale publication without nested store/transport locks.
- HTTPD remains bounded to six sockets, two serial WebSockets, one admin WebSocket and 39 method/path handlers; LRU eviction is disabled. Sessions, sockets, tickets and the two shared remote-console slots are separate capacity limits. Optional settings/admin failures preserve unrelated routes where their initialization contract permits; UART0 and native USB remain independent of web readiness.

`web_httpd_adapter` alone accesses private IDF 5.5.0 HTTPD state. It rejects duplicate/ambiguous headers, postpones 101 until admission, and wipes consumed header scratch while preserving right-aligned unread bytes. Optional Settings registration stages descriptor/name allocations before publishing either, avoiding the pinned public registration failure path. Re-audit these private boundaries on SDK upgrades and same-version SDK patches: the version guard does not detect patches that retain the same version number. HTTPD response headers are pointer-backed, not copied; both `Set-Cookie` value buffers must remain valid and distinct through response send. Do not reuse or wipe those buffers before sending completes. Do not enable header/ticket debug logging. Auth documents, scripts and sensitive responses are no-store with CSP/no-referrer/frame-denial protections; authored loader changes require matching CSP hashes. Generated assets are not a normal documentation/build output.

## Terminal and console ownership

Switching Serial/Admin/Settings never creates a second serial client, requests/releases the writer lease or reconnects serial. Hidden connected terminals keep draining; only selected terminal input is sent. Both browser terminals have separate 5,000-line scrollback and 64 KiB callback-accounted pending-output bounds with visible browser-drop counts. Admin input is bounded to 4 KiB admission and 512-byte frames. Admin open/reopen is explicit; admin close is isolated. Disconnect pauses serial reconnect but retains login; logout/expiry/revocation closes affected sockets normally.

The document binds terminal state to its first validated username/role/session-stable CSRF tuple. A different identity requires a clean document before showing retained output. Pagehide fences sockets/work and hides scrollback until same-session revalidation; admin is not automatically reopened. Fit readiness caches only success and uses at most three generation-fenced animation-frame retries per external request.

`admin_ssh_console` is the sole `esp_console_run()` caller for UART0, admin SSH and browser admin. Two fixed remote-console slots are shared across SSH/browser, not two per transport. Queue records carry copied principals and transport-qualified generation tokens. Owner currentness is checked outside console locks before commands and during prompts (250 ms polling plus validation/scheduling latency), then identity is rechecked. This is operation admission, not cancellation or rollback of arbitrary executing handlers. Consumed output and retired prompt/history state are wiped.

HTTPD alone owns browser-admin socket IO and its 1,552-byte PSRAM-only payload. A 20 ms timer queues at most one owner poll, not a new task. Close uses current-owner shutdown, not queued reusable `sock_db *` pointers. Detach fences submitters; queued state retires only after successful HTTPD destruction. Failed destruction retains ownership and prevents unsafe restart/reuse.

### Browser-shell policy

Typed Settings permissions do not expand shell permissions. Parsed canonical arguments, not raw prefixes or completion suggestions, control admission:

- Browser `web` permits only `web status`, `web stop`, and exact `web certificate rotate --force`; certificate info/reset, diagnostics/performance and other web forms are denied.
- Browser `wifi`/`mdns` permit only status. Network mutation belongs to typed Settings or UART0/admin SSH.
- Browser `user` permits status/list/show and interactive add/password plus forced role/delete for **other accounts only**. Self changes, generated passwords, key commands and recovery are denied there; typed Accounts supports the separately bounded self/generated/key workflows.
- Browser SSH stop/disconnect/reset and host-key mutation are denied; typed SSH Settings has its own safe owner path. Do not claim full browser-shell parity.
- Browser `reboot` and owner-relative `exit` are supported. First-admin provisioning uses normal `user add` on UART0; unavailable-database recovery is UART0-only. The legacy `user bootstrap` and web credential commands no longer exist.

Self-affecting shell actions use the existing bounded drain/control path (up to ten seconds plus a short delay), not guaranteed peer delivery. Browser certificate rotation hands a typed action after drain/200 ms to the existing 12 KiB dispatcher, never crypto/NVS on the 4 KiB control stack. Pending input is discarded through execution, and an executing slot remains reserved across self-detach. UART0/admin SSH retain canonical recovery actions.

## Typed settings API and operation lifetime

All routes below are under `/api/settings/`. Each domain has bodyless GET snapshot plus GET/POST operation unless noted. Requests reject queries, malformed/oversized/duplicate/unknown fields and inappropriate bodies; mutation routes require bounded JSON with current admin/Origin/CSRF. GET allows absent Origin but rejects mismatch. Snapshot contention/unavailability is not an empty successful projection. HTTPD performs bounded admission/encoding only; canonical mutations run on the existing four-entry administration dispatcher using **IDs only**, not command strings, credentials, request pointers or socket handles.

| Domain and source | Snapshot / operation suffix | Request / snapshot / result buffer bounds (bytes) |
|---|---|---|
| `web_serial_settings`, serial service | `serial` / `serial-operation` | 256 / 256 / 96 |
| `web_account_settings`, user database | `accounts` / `account-operation` | 768 / 1024 (accounts), 512 (keys) / 96 |
| `web_network_settings`, Wi-Fi + mDNS | `network` / `network-operation` | 768 / 2048 / 128 |
| `web_display_settings`, local status UI | `display` / `display-operation` | 256 / 128 / 96 |
| `web_broker_settings`, session broker | `broker` / `broker-operation` | 256 / 2048 / 96 |
| `web_ssh_settings`, SSH owner/security | `ssh` / `ssh-operation` | 256 / 768 / 96 |
| `web_lifecycle_settings`, HTTPS owner/security | `lifecycle` / `lifecycle-operation` | 256 / 320 / 96 |

Mutation bodies use at most four receive attempts. Each domain retains one original-login-bound pending/result slot, nonreused operation IDs and an executing reservation. Results are replaceable, login-isolated observations, not durable history or idempotency keys. Another tab can replace a completed result. Dispatcher currentness and the 30-second dequeue deadline precede canonical owner admission. **Admitted work may finish after logout, revocation, timeout or navigation.** A failed response, 401 or disappearance of a result proves neither success nor cancellation; inspect current state before any deliberate retry.

Accounts and Network each use a one-second timer to cancel/wipe queued, non-executing secrets after 30 seconds plus scheduling latency. Shared input wipes on dequeue/rejection; executing locals wipe on return. This is not a hard wall-clock erasure/execution guarantee. Other domain deadlines are dequeue checks, not new cancellation timers. UI fences late/session-changed responses, bounds request/result checking to 15 seconds and never automatically replays/restores mutations. Serial/Accounts/Network/Display/Broker use bounded automatic checks where implemented (at most ten one-second GETs); SSH and HTTPS/Reboot require manual Check Result/Refresh.

### Serial and Display

Serial Apply/Defaults change RAM; Save persists working device state, not browser drafts. Load follows canonical defaults/fallback behavior. Reset uses canonical apply/persist/best-effort rollback. Reconfiguration/stop discards serial-service RX/TX and task-local pending data but preserves broker clients, lease and already-fanned output. USB with DTR may restart a stopped service. `/api/status` uses a zero-wait consistent serial snapshot (`running:null` if unavailable).

Display accepts dim/off timeouts 0–86400 seconds and an expected nonzero configuration generation. All writers, including CLI/legacy Apply, share a zero-wait owner reservation; NVS runs outside critical sections. Save stabilizes selected RAM; Load retains canonical fallback without rewriting NVS; Reset commits defaults **before** RAM publication, leaving RAM unchanged on failure. Buttons/diagnostic holds update activity, not configuration generation. Configuration needs an available UI task, not a physically present panel, and never takes over I2C.

### Accounts and authorized keys

The database owns eight accounts, final-admin protection and conditional target username/account-ID/auth-generation checks inside its mutation lock. Create/password/role/delete and key mutations share canonical commit/invariant logic. HTTPD uses zero-wait secret-free projections, not blocking CLI snapshots. Successful mutations request target-only web/SSH revocation; self mutation can revoke access before result retrieval.

Separate bodyless POST `accounts/generate-password` returns one 24-character value without mutation or retained retrieval. The browser uses a 60-second context-bound saved acknowledgement before separate submission; this is UX, not delivery proof, and JavaScript strings cannot be securely wiped. POST `accounts/keys` returns only slot/type/SHA-256 fingerprints for the selected identity. Key add/delete/clear share the operation slot; public-key import is at most 384 decoded text bytes in the 768-byte request and uses canonical Ed25519/P-256 validation. Three stable key indices may be sparse; never interpret response-array position as an index. No stored key blob, verifier or password is exported.

### Network

Wi-Fi config/runtime is one zero-wait consistent projection; mDNS is a separate projection, not cross-domain atomic authorization. Four stable profiles carry enabled/priority/security/SSID/password-configured metadata. `mixed` means WPA2-or-stronger, not open. `announced` is expected STA announcement, not verified DNS.

SSID wire values are reversible **bytes**, maximum 32: printable ASCII, standard single-character JSON escapes and `\u00HH`, with no raw non-ASCII, non-byte Unicode or surrogates. NUL/non-UTF-8 round-trip. UI text is UTF-8-encoded before byte serialization; exact reversible text or literal hex preserves existing bytes and BOM, with no silent replacement/truncation.

Flat operations select one domain/target:

- `wifi-patch` + Wi-Fi generation: optional boot policy, AP policy/channel/SSID/password/clear; `profile-patch` additionally selects stable profile 0–3 and optional enabled/priority/security.
- `wifi-save|wifi-load` require Wi-Fi generation. `start|stop|reconnect|next-profile` use canonical connection controls, not explicit selected-profile connection.
- `mdns-set` requires its generation and suffix; `mdns-save|mdns-load|mdns-defaults` require its generation. Suffix is 1–55 lowercase ASCII letters/digits/hyphens, no leading/trailing hyphen, producing `sak-<suffix>`.

Omitted fields preserve current bytes under the Wi-Fi mutex. Password Keep omits, Replace is 8–63 printable ASCII bytes, disabled-STA Clear is explicit; replacement and clear cannot coexist. AP clear is always denied, even while off. No saved PSK or length is returned. Wi-Fi compare/merge/whole-candidate validation and required queue admission precede RAM publication. Save stabilizes selected bytes; Load reads stored configuration only and cannot generate fallback secrets. No browser Wi-Fi reset/default-secret/export route exists.

Edits require explicit Save. Disabled-profile-only edits do not restart active radio; enabled-policy/AP changes follow canonical asynchronous restart. Start/Stop change RAM enabled-at-boot; Reconnect/Next are no-ops while stopped. Next follows enabled priority order with wrap; editor selection is not connection selection. mDNS independently owns generation/persistence; the Wi-Fi manager owns radio/reannouncement. mDNS RAM change followed by queue failure is reported without rollback; its Load may choose deterministic MAC-derived defaults.

Network result fields are `id/action/state/error`: `pending`, `accepted`, `ok`, `failed`, `cancelled`, `stale`, `invalid`, `loaded_defaults`, `applied_not_queued`, or login-isolated `idle`. `accepted` means RAM/owner-queue admission, **not** association/DHCP/DNS completion. `ok` denotes explicit Save. Loss can precede response; recover via STA/AP and inspect before retrying. UART0 administers recovery; native USB provides network-independent UART1, not an admin console.

### Broker and contextual controls

Broker management atomically copies eight compact client rows, writer and lease generation under one zero-wait mutex acquisition, without reading UART payloads or consuming events. Conditional assignment compares the selected nonzero target ID and lease generation under the same force-writer lock before any effects. Stale/absent targets conflict; same-current-target assignment is a no-op only after validation. Accepted serial TX is not recalled by transfer.

IDs have three slot bits and 29 generation bits; exhausted client slots retire until reboot rather than wrap. The separate 32-bit lease version saturates at UINT32_MAX, survives counter clear and advances on grant/release/revoke before advisory event delivery. Forced transfer can advance twice; it is not a count. Saturation blocks typed assignment but leaves ordinary request/release/disconnect and canonical recovery force available. Reboot invalidates old browser sessions.

Serial/Wi-Fi/Broker quick views reuse one nonmodal settings host and existing controllers/drafts, not parallel editors. Hover/focus/click/tap never mutate. Network quick mode excludes password controls. Full-page drafts are protected; promotion preserves controller/selection, departure fences reads/timers without cancelling admitted work. Dismissal restores the prior terminal without stealing unrelated focus; explicit Escape/Close returns focus to its trigger.

Broker contextual reads use one timer five seconds after successful completion and a five-second whole-read deadline, stopping on errors/uncertainty/departure. Explicit target/lease selection is not rebased by refresh. Sticky stale/absence latches require deliberate reselection even if later snapshots match again. Confirmation captures exact versions before session revalidation; guarded aria-disabled controls preserve focus during updates.

## Service lifecycle and identity rotation

Service generations are saturated, distinct from identity and session generations, and advance on admitted canonical lifecycle attempts including failures; counter clear/reinit cannot revive stale versions. Public zero-wait metadata authorizes nothing. Conditional controls compare under the canonical owner reservation; no snapshot-check/unconditional-mutate gap is allowed. Reboot invalidates originating logins and boot-local reservation IDs.

### HTTPS and reboot

GET `lifecycle` has seven fields: `generation`, `running`, `transitioning`, `controllable`, `identity_generation`, `fingerprint`, `rotatable`. Stored HTTPS fingerprint is 64 lowercase hex SHA-256 digits. Stop/restart/reboot require exactly action + service generation; rotate also requires identity generation. Unknown/duplicate/escaped/coerced fields and zero/saturated versions reject. Unavailable identity yields generation zero/empty fingerprint/not rotatable without removing ordinary service controls.

Self-cutting HTTP actions use **successful synchronous send return → one nonreused-ID HTTPD callback → existing dispatcher**. Send return is not browser receipt. The callback never waits or performs lifecycle work, and captures no request/fd/reusable operation pointer. A two-second ACK admission deadline and post-validation 30-second dequeue deadline are not execution bounds. Accepted-but-lost HTTPD work retains one reservation until callback arrival or successful HTTPD destruction; failed destruction cannot release it or accumulate more callbacks. The original login/current admin is revalidated before owner admission.

`web_server_stop_current()`/`web_server_restart_current()` compare and reserve under the server mutex. Restart retains transition ownership through stop/start; failed stop skips start, failed cleanup retains handles and canonical recovery, and reinit preserves the error. `web_server_reboot_current()` reserves the HTTPS generation then uses canonical `esp_restart()` outside locks, not an HTTPD stop wait or self-console cleanup.

`web_server_replace_identity(service_generation, identity_generation, reset, &committed)` reserves **service before identity**, before any crypto/storage. Both nonzero generations mean conditional healthy-running rotation; both zero retain CLI semantics; conditional Reset is invalid. Canonical CLI/browser-shell rotation and direct security rotate/reset share nonreused task-owner-bound identity reservation tokens. Only the owner can replace once/release; exhaustion fails closed until reboot. Crypto/NVS run outside service/security mutexes and spinlocks; commit precedes live publication and old-key wipe. Reservation remains held while reserved start copies the committed pair.

HTTPS ordering is **commit → stop → restart**. Precommit generation/RNG/storage failure leaves identity, HTTPD and logins unchanged (service version may advance after admission). Postcommit lifecycle failure never rolls back identity; failed stop can leave old served and new stored fingerprints different. Running replacement restarts HTTPS; canonical stopped rotation stays stopped, while CLI TLS-only reset can recover unavailable identity and starts a stopped service. Browser has no Reset/recovery/export action.

Save drafts; rotation/restart invalidates all web logins and closes both browser routes. Inspect `web certificate info` through trusted UART0, verify fingerprint before renewing trust, then reload/sign in freshly. Accepting a warning alone is not trusted verification. Use canonical UART0/admin SSH `web stop` / `web start` for retained-server recovery. Network/SSH/USB are not stopped by HTTPS-only operations; whole-device reboot interrupts all transports and loses unsaved RAM.

### SSH

GET `ssh` supplies service/session state plus identity generation, fixed P-256 algorithm, unpadded OpenSSH `SHA256:` base64 fingerprint and rotatable flag. Service actions use exactly `action`, `generation`, `target`; rotate adds `identity_generation` and requires target zero. Start/stop and exact-session disconnect use published state, saturated service generation and the command mutex; exhausted SSH session slots retire rather than wrap. Disconnect success is an owner close request, not completed teardown. HTTPD never calls wolfSSH or waits for the SSH task.

`ssh_transport_replace_identity()` compares/reserves **service then identity before stop or storage**, holding the existing command mutex across **stop → generate/commit/publish → conditional restart**. Canonical UART0/deferred admin-SSH rotation/reset and direct security mutations share the task-bound nonreused identity reservation. Crypto/NVS run outside security locks/spinlocks. Both nonzero versions select conditional rotation (also while stopped); both zero preserve canonical semantics, with no conditional Reset.

Failed stop/timeout skips mutation and never starts again; pending owner work is not cancelled. Persistence failure after successful stop may already have disconnected clients and attempts old-identity restart if previously running. Committed replacement remains committed if restart fails. Stopped rotation stays stopped; canonical reset can recover unavailable material/start stopped SSH. Only the SSH owner frees runtime context after all slots retire, before clearing cleanup admission; start rejects orphan handles. wolfSSH copies DER into its context; caller/candidate/superseded private bytes are wiped.

SSH changes leave invoking HTTPS available, so they use the ordinary ID-dispatcher/result path, not HTTPS's self-cutting ACK gate. UI confirms both versions and all-SSH/session scope, retains stale selection and manual 15-second/no-replay flow. A failed result may represent partial effects. Verify new trust through UART0 `ssh host-key info` before updating known_hosts; no HTTPS relogin is inherently required. Browser Reset/recovery/key export and user authorized-key changes are separate, excluded from host rotation.

## Diagnostics, recovery and scope boundaries

See [admission diagnostics](web_admission_diagnostics.md), [ordinary HTTPS idle cleanup](https_idle_cleanup.md), [throughput diagnostics](web_throughput_diagnostics.md) and [legacy storage compatibility](legacy_credential_removal.md). Broker read means transport handoff, not peer receipt; capture non-consuming counters before disconnect. TLS `-0x004C` is generic NET_RECV_FAILED, not evidence of OOM. Resource minima and counter observations require attribution, not inferred causes.

Phase 8D.15's dedicated typed network-diagnostics UI/API was removed: diagnostics remain shell-based, subject to frontend policy. The unimplemented 8D.19 ordinary browser-session/native-USB control expansion was removed; existing SSH controls remain. No full shell parity, browser identity recovery/reset/export, encryption, secure boot or OTA is implied by acceptance. UART0 is the administrative recovery authority; native USB is binary-transparent, network-independent UART1 access. Neither permits bypassing the broker's single writer or recalling already-admitted work.