# Local Identity

Local Identity is a zero-dependency, file-based user management capability
for net-kingdom bootstrap environments — systems that do not yet have (or do
not need) a running Keycloak instance.

## Why it exists

In net-kingdom, Keycloak is the production identity provider. But Keycloak
requires a running Kubernetes cluster, a database, and a configured realm
before it can authenticate anyone. This creates a bootstrapping paradox:

> You need identity to set up infrastructure, but the infrastructure provides
> identity.

Local Identity breaks this cycle. An operator with only a Linux home directory
can establish their identity, generate deterministic test users, and run
dev/test applications with OIDC authentication — before any service is
deployed.

## Design principles

1. **Zero dependencies** — only the Linux filesystem; no Docker, no K8s, no
   running services required.
2. **Derived identity** — the primary user is derived from `$USER`,
   `/etc/passwd` (GECOS), and a configured email address. No manual setup
   required for the basic case.
3. **Deterministic test users** — two test users are auto-generated from the
   primary user at `init` time using `N` and `+testN` suffixes:

   | Field    | Primary     | Test 1              | Test 2              |
   |----------|-------------|---------------------|---------------------|
   | username | `$USER`     | `${USER}1`          | `${USER}2`          |
   | fullname | GECOS field | `<fullname>+test1`  | `<fullname>+test2`  |
   | email    | configured  | `<user>+test1@…`    | `<user>+test2@…`    |

   Email aliases follow the Gmail `+xxx` convention so test emails route to
   the operator's inbox without extra accounts.

4. **Hard isolation** — test users carry `environment: local`; production
   connectors reject this flag by default. Test users cannot authenticate in
   production without an explicit override.
5. **Minimal OIDC** — a lightweight native OIDC provider backed by the file
   store, for apps that require OIDC in dev/test without a running Keycloak.
   Tokens carry `iss: local-identity`; production systems are configured to
   reject this issuer.
6. **Secure by default** — `~/.local-identity/` is created with mode `700`;
   individual user files with mode `600`; the tool validates permissions on
   every startup and refuses to run if the store is world-readable.

## What it is not

- **Not a production identity provider.** Local Identity is never exposed to
  the internet. It has no MFA. It is not hardened for public traffic.
- **Not a replacement for Keycloak.** Once a cluster is operational, Keycloak
  is the IdP. Local Identity provides an on-ramp, not an alternative.
- **Not multi-user.** Local Identity is single-operator: one primary user
  derived from the Linux session, plus generated test users.
- **Not an LDAP/AD/Entra bridge.** Enterprise federation is handled by
  Keycloak. See EP-NK-001 in the State Hub.
- **No MFA.** Second factors are out of scope; this is intentionally minimal.

## User schema

Users are stored as YAML files under `~/.local-identity/users/`:

```yaml
# ~/.local-identity/users/tegwick.yaml
schema_version: "1"
username: tegwick
fullname: "Bernd Worsch"
email: "bernd.worsch@gmail.com"
environment: local          # never "production" for local-identity users
generated: false            # true for auto-generated test users
production_identity:        # optional: maps this user to a production identity
  username: tegwick
  realm: net-kingdom
```

Test users are generated at `init` time and stored alongside:

```yaml
# ~/.local-identity/users/tegwick1.yaml
schema_version: "1"
username: tegwick1
fullname: "Bernd Worsch+test1"
email: "bernd.worsch+test1@gmail.com"
environment: local
generated: true
source_user: tegwick
production_identity:        # optional: can map to a test/staging account
  username: tegwick-test1
  realm: net-kingdom
```

## Sandbox → production mapping

Each user file can optionally carry a `production_identity` block. When an
entity owned by a local-identity user needs to be transferred to a production
environment (e.g. a resource created during local development), the mapping
provides the correct production user ID.

`local-identity export <user>` produces a Keycloak-compatible user JSON that
respects this mapping. The schema is validated against the Keycloak user
representation to prevent silent drift.

## CLI reference

```
local-identity init                      # derive primary user, generate test users
local-identity list                      # list all users in the store
local-identity show <username>           # display user file
local-identity export <username>         # emit Keycloak-compatible JSON
local-identity serve [--port P] [--ttl T]  # start minimal OIDC server
local-identity security-check           # validate filesystem permissions
local-identity revoke-token <jti|jwt>   # add a token JTI to the revocation list
```

## OIDC provider (Stage 3)

When running `local-identity serve`, a minimal OIDC Authorization Code flow
server starts on localhost. It supports:

- `GET /.well-known/openid-configuration` — discovery document
- Authorization endpoint, token endpoint, userinfo endpoint
- JWT tokens with `iss: local-identity` (hard-coded; production systems
  reject this issuer by default)
- Auto-generated self-signed TLS certificate

This allows dev/test applications to use standard OIDC libraries against
Local Identity without any Keycloak dependency.

**Security note:** the OIDC server binds to `127.0.0.1` only. Never expose
it on a public interface.

## Risks and mitigations

| Risk | Mitigation |
|------|------------|
| World-readable credential files | `~/.local-identity/` mode `700`; startup check fails loudly |
| Test users leaking into production | `environment: local` flag; production connectors reject by default |
| Local Identity tokens accepted in production | `iss: local-identity`; configure production Keycloak to reject this issuer |
| File schema drifting from Keycloak model | `export` command validates against Keycloak representation; schema is versioned |
| Bootstrap store becoming a long-lived crutch | Explicit scope limit: once Keycloak is operational, migrate and stop using Local Identity |

## Keycloak import procedure

Once the Keycloak realm is operational (NK-WP-0001 T06), migrate the primary
user from Local Identity into Keycloak using the partial import endpoint.

**1. Export the primary user:**

```bash
local-identity export --all --realm net-kingdom > /tmp/li-import.json
# By default, only the primary user is exported (test users are excluded).
# Check: the Note line on stderr confirms how many test users were skipped.
```

**2. Import via the Keycloak Admin REST API:**

```bash
# Requires a Keycloak admin token
TOKEN=$(curl -s -X POST https://keycloak.yourdomain.com/realms/master/protocol/openid-connect/token \
  -d "client_id=admin-cli&grant_type=password&username=admin&password=<admin-pw>" \
  | jq -r .access_token)

curl -s -X POST \
  https://keycloak.yourdomain.com/admin/realms/net-kingdom/partialImport \
  -H "Authorization: Bearer $TOKEN" \
  -H "Content-Type: application/json" \
  -d @/tmp/li-import.json
```

**3. Set a password in Keycloak** (Local Identity does not export credentials):

```bash
curl -s -X PUT \
  https://keycloak.yourdomain.com/admin/realms/net-kingdom/users/<user-id>/reset-password \
  -H "Authorization: Bearer $TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"type":"password","value":"<new-password>","temporary":false}'
```

**4. Retire Local Identity for this instance:**
Once the user is operational in Keycloak, stop using `local-identity serve`
for this environment and remove the store: `rm -rf ~/.local-identity`.

## Isolation guarantee

All users exported by Local Identity carry the attribute:

```json
"attributes": {
  "local_identity_environment": ["local"]
}
```

Generated test users additionally carry `local_identity_generated: ["true"]`.

### Configuring Keycloak to reject local-identity users

Add a condition to the Keycloak browser authentication flow that denies login
for any user with `local_identity_environment = local`. This is a
defence-in-depth measure: even if test users are accidentally imported into a
production realm, they cannot authenticate.

In Keycloak 23+, use a **Conditional Authenticator** with a User Attribute
Condition:

1. In the realm's **Authentication → Flows → browser** flow, add a sub-flow.
2. Add the **Condition - User Attribute** authenticator.
3. Configure: attribute = `local_identity_environment`, value = `local`,
   negation = **false** (matches when attribute equals the value).
4. Set the sub-flow to **DENY** when the condition is true.

Alternatively, use a Keycloak script authenticator or a custom policy enforcer.

### Production identity mapping

Before importing, you can assign a `production_identity` block to the user
so the Keycloak username differs from the local username:

```yaml
# ~/.local-identity/users/tegwick.yaml
production_identity:
  username: bworsch      # the username used in the production realm
  realm: net-kingdom
```

Re-run `local-identity export --all` — the exported JSON will use `bworsch`
as the Keycloak username and a deterministic UUID derived from `net-kingdom/bworsch`.

## Security model

### Threat model

Local Identity is designed for **single-operator, localhost-only** use. The
threat model covers accidental exposure, not active adversarial attack.

| Threat | Control |
|--------|---------|
| Other local users reading credential files | `~/.local-identity/` mode `700`; user files mode `600`; startup check exits on violation |
| Attacker elevates a local OIDC token to production | `iss: local-identity` rejected by production Keycloak; `environment: local` attribute rejected by Keycloak attribute check |
| Stolen token used after the fact | Token revocation list (`revoke-token <jti>`); configurable TTL (default 1h) |
| Long-lived store left behind post-migration | Explicit retirement step: `rm -rf ~/.local-identity` after Keycloak migration |
| OIDC server exposed on non-loopback interface | Server hard-codes `127.0.0.1`; `0.0.0.0` binding is not offered |

### Assumptions

- The operator's Linux account is not compromised (Local Identity cannot
  protect against a root-level attacker).
- The `LOCAL_IDENTITY_HOME` environment variable is not set to a
  world-readable path by accident.
- The operator's umask does not silently widen permissions before the tool
  can apply `os.chmod`. (The tool sets permissions explicitly after every
  write, which limits this window.)

### Non-guarantees

- **No MFA.** Token issuance requires only user selection in the browser
  form; there is no second factor.
- **No audit-log integrity.** `audit.log` is append-only by convention, but
  the OS does not enforce append-only at the file level without `chattr +a`
  (which requires root). The log records events; it does not prove they were
  not tampered with.
- **Self-signed TLS is not CA-trusted.** The TLS certificate generated for
  `local-identity serve` is not signed by a trusted CA. OIDC clients must
  either skip certificate verification or import the certificate manually.
- **No privilege separation.** All operations run as the operator's user.

### Optional SELinux / AppArmor hardening

If your system uses SELinux or AppArmor you can apply labels to further
restrict access to `~/.local-identity/`:

**SELinux** (example — adapt context type for your policy):
```bash
chcon -R -t user_home_t ~/.local-identity
```

**AppArmor** — create a profile snippet that denies access to
`~/.local-identity/` from any process other than `local-identity`:
```
deny /home/*/.local-identity/ r,
deny /home/*/.local-identity/** r,
```

These are optional hardening layers. The tool's own permission controls
(mode 700/600, startup enforcement) provide the baseline.

### Token revocation

Tokens issued by `local-identity serve` can be revoked at any time:

```bash
# By JTI (extract from JWT payload manually or from audit.log):
local-identity revoke-token <jti-uuid>

# By passing the full JWT — the JTI is extracted automatically:
local-identity revoke-token <jwt-string>
```

Revoked JTIs are stored in `~/.local-identity/revoked.json` (mode 600).
The revocation list is checked on every `/userinfo` request. There is no
endpoint to un-revoke a token; if you need to re-grant access, obtain a
new token via the authorization code flow.

## Relationship to the SSO platform

Local Identity is a complementary workstream to the SSO & MFA Platform
(NK-WP-0001). The SSO platform provides production-grade identity; Local
Identity provides the bootstrap path that allows the SSO platform itself to
be set up and tested.

Implementation: see [NK-WP-0002](../workplans/NK-WP-0002-local-identity.md).