Ekklesia/docs/development/security.md

Security model and deployment trust boundaries

The one canonical statement of what Ekklesia's boundaries actually protect against today, and what they do not. Read it before installing a module, exposing the API, or reasoning about any other document's guarantees.

Related: ADR 0006 (compiled module runtime), ADR 0016 (module database access), ADR 0020 (module routing/lifecycle and migration execution), and Module development.

Installed modules are trusted compiled backend code

Installing a module is equivalent to deploying trusted server code. It is not equivalent to installing a browser extension, a plugin from a marketplace, or anything else with a security boundary around it. There is no such boundary here.

A module's dist/server entrypoint is imported into, and runs arbitrary JavaScript inside, the apps/api process. Within the operating-system account that process runs as, a module can:

• read and write any file the account can reach, including .env, TLS material, and the source tree;
• read process.env, process.argv, and any other process state;
• open outbound network connections and bind listeners;
• import any installed dependency, including ones Ekklesia never intended it to use;
• monkey-patch Core's own exports, Node built-ins, globalThis, or another module's objects;
• keep running work after its lifecycle hooks return.

It also shares the API's single PostgreSQL role and connection pool. ModuleDatabase.execute accepts arbitrary SQL, so a module has exactly the database authority the API has — every table in the database, including ekklesia_core_user, ekklesia_core_grant, ekklesia_core_platform_owner, ekklesia_core_platform_owner_bootstrap, ekklesia_core_authorization_audit, and every other module's tables.

What the module-facing mechanisms actually are

These are correctness and coordination boundaries. Every one of them assumes the module is cooperative. None of them constrains a module that is not:

Mechanism	What it actually provides
ekklesia_* table prefixes and schema discovery	Ownership clarity and collision avoidance between cooperating modules
TypeScript types, branded ids, contracts	Compile-time correctness; erased at runtime
ekklesia.module.json manifest and manifestVersion	Declared compatibility and dependency ordering
Permission declarations and the composed registry	Which permissions this module's own routes may name, checked when Core mounts them
Route validation, overlap rejection, body limits	Deterministic, unambiguous HTTP routing and request bounds
Object.freeze on contexts and services	Prevents accidental mutation; a module can still reach the underlying objects
The ModuleDatabase facade	A typed, ergonomic surface — not a privilege reduction, since execute is arbitrary SQL
Capability registry	Explicit inter-module wiring, not access control
Bounded stop/rollback deadlines (ADR 0020)	The platform stops waiting; module code is not cancelled or terminated

There is no process, container, VM, seccomp/syscall, filesystem, network, PostgreSQL role, schema-permission, table-ACL, row-level-security, tenant, or resource sandbox between a module and Core. A module is not isolated from Core, from other modules, or from the host.

ADR 0021 lets a module declare its own UI entrypoint. That changes nothing about the authority described above. A module that ships UI is exactly as trusted as one that does not: its server entrypoint still runs in the API process with that authority, and declaring entrypoints.ui neither adds nor implies any isolation.

Module UI is trusted browser code, in the host's own realm

ADR 0022 decides the browser-side model that ADR 0021 deliberately left open. Module UI runs in the same browser JavaScript realm as the host shell: no iframe, no sandbox, no cross-origin isolation, no capability confinement. A module's UI can reach the host page, the DOM, window, and any global the browser exposes, exactly like any other script the application loads.

That is a deliberate choice for a first-party, trusted-module platform, and it is consistent rather than lax: a module whose server code already runs in the API process with the API's full PostgreSQL authority is not meaningfully constrained by sandboxing its browser half. Do not describe module UI as sandboxed, isolated, or confined — none of those are true, and no mechanism in this repository implements them.

The contract does leave room for a future sandboxed tier without a redesign: mount(container, context) passes an element and a plain-data context rather than shared object graphs, so a host could implement it against an isolated realm. Nothing does today.

Loading a module UI executes trusted code in the host page

@ekklesia/module-ui-host dynamically imports a module's compiled artifact from a URL and mounts it (ADR 0024). Once imported, that artifact is ordinary same-realm JavaScript: it can reach the DOM, window, and anything else the page can. The loader is not a sandbox. It validates that the artifact is the module the host expected — the right id, the right version, a well-formed default export — and refuses to mount anything else, but that is an integrity check against a stale or mismatched bundle. It is not a judgement about whether a module is safe, and it must never be described as one.

The publication side carries the real obligation, and it now exists (ADR 0025). It honours the rule this section demanded of it: the existence of an artifact on disk is not what makes it servable. A module is publishable only if it is in the validated set the API accepted at startup and its manifest declares entrypoints.ui.

Publishing a module UI artifact exposes one file, not a directory

GET /api/v1/module-ui/<module-id>/<version> serves an installed module's compiled UI artifact. Both segments are lookup keys, not path components: they are matched against a registry Core built from discovered modules, and only an exact match causes the canonical path discovery already resolved and containment-checked to be read. No request value is composed into a filesystem path and the route declares no wildcard segment, so traversal, encoded separators, sibling bundle chunks, package-root files (package.json, .env), and source maps are unreachable — not filtered out, but with no code path that could reach them. @ekklesia/module-ui-build emits a real .map next to every artifact, and it is deliberately not served: the manifest declares the entrypoint and nothing else, and a source map embeds sourcesContent.

The server never executes what it publishes. The route reads bytes and writes bytes — no import, no evaluation, no transformation — so a module UI whose top level throws is served like any other, and ADR 0021's rule that discovery never runs entrypoints.ui is unchanged.

The route requires no authentication, and that is a decision with a stated cost. Retrieving the artifact confers no authority: the bundle carries no credential, the host (not the artifact) supplies the principal and permissions at mount time, and every module API remains behind requirePermission. Requiring a session would also break cross-origin dynamic import(), which sends no cookie. The cost is that an anonymous caller who already knows a module id and its exact installed version can download that module's UI bundle, and thereby learn the module is installed. That is information disclosure, not authority. Unknown module, no declared UI, and wrong version return one identical 404, so the route is not an enumeration oracle — but an operator who needs the bundle itself confidential must keep the API off untrusted networks, exactly as the deployment assumptions below already require.

Trust in a published artifact rests on discovery-time validation plus a request-time read of that exact path. There is no signing, hashing, or provenance verification — Ekklesia has none to verify against — so publication is not evidence that a module is safe. Only installed, reviewed modules may be published or mounted. A module UI that mounts has gained no privilege it did not already have — its server half already runs in the API process with the API's database authority — and server APIs remain the sole authority for authorization regardless of what a browser loaded.

Client-side permission checks are not a security boundary

A host may tell a module UI what permissions it believes the viewer holds (ModuleUiPermissions.has), so the UI can hide an action or disable a control. This is presentation only. Server-side authorization remains the sole authority: every module route is enforced by requirePermission against the composed platform permission registry, and that enforcement neither knows nor cares what a browser decided. Hiding a control is a usability improvement, never an access control. Treat any claim that a UI check protects anything as a bug.

What this platform must not claim

Ekklesia today has none of the following, and no document, README, or marketing surface may imply otherwise:

• module signing, provenance attestation, or verified publishers;
• a marketplace, registry, or review process for third-party modules;
• sandboxed or hot-installed modules;
• per-module database roles, schemas, or credentials;
• tenant isolation;
• runtime resource limits (CPU, memory, file descriptors, connections) per module.

Operator rule

Only install modules whose source, provenance, and build output you have reviewed and whose authors you trust with your production server and database. Treat a module the way you would treat a direct commit to apps/api: read the code, verify what artifact was built from it, pin it, and re-review on upgrade. Do not install a module because a manifest looks well-formed — every validation Ekklesia performs on a manifest is satisfied trivially by hostile code.

Installing, removing, or editing a module requires an API restart; there is no hot install path, and none should be added while this model holds.

What would have to change before accepting untrusted modules

Accepting third-party modules that have not been reviewed is an architectural change, not a configuration change. At minimum it would require:

• process or container isolation per module, with the API as a supervisor;
• capability-based RPC across that boundary instead of in-process object passing;
• a separate PostgreSQL role and schema per module, with no shared superuser-equivalent pool;
• restricted filesystem and network access per module;
• CPU/memory/connection limits and enforced timeouts that can actually terminate work;
• signed, verifiable module provenance and a defined review/revocation process.

Until that exists, the trusted-code model above is the security model.

Current deployment state

As of this branch, Ekklesia is not deployed. There is no production API instance, no reverse proxy, no public listener, and no deployment automation of any kind in this repository — no deploy script, no CI deployment step, no container publish, no orchestration manifest. No .env has ever been committed; only .env.example.

Two production defaults are relevant but are not by themselves a deployment guarantee:

• apps/api defaults its listen address to loopback (127.0.0.1), so it is not reachable off-host unless an operator explicitly changes it;
• production configuration refuses to enable public signup at all (PUBLIC_SIGNUP_UNSUPPORTED_IN_PRODUCTION).

A loopback default is not a firewall, and a config default is not a verified boundary.

Launch checklist — each item must be proven against the real deployment before public exposure

Until every one of these is verified on the actual hosts, the deployment is not launch-ready. None of them can be satisfied by reading this repository.

This checklist gates a public launch. It does not gate development: Surfaces, modules, and Core work all proceed against the local development infrastructure while every item below is still outstanding.

1. The reverse-proxy path serves the API successfully.
2. The origin port is unreachable from the public Internet.
3. The origin port is also unreachable from any untrusted network/VLAN — only the intended private proxy path connects. Security must not depend on an unpublished DNS name or origin IP.
4. The proxy overwrites (never appends to, never passes through) the client-IP header Ekklesia is configured to trust.
5. Rotating a caller-supplied Forwarded, X-Forwarded-For, CF-Connecting-IP, X-Real-IP, or the platform's own internal sanitized header cannot rotate the authentication rate-limit bucket.
6. The actual immediate proxy peer is in Ekklesia's explicit trusted-proxy set, and an untrusted direct peer's forwarded header is ignored.
7. Proxy logs do not record cookies, authorization values, request bodies, or raw forwarding chains.
8. PostgreSQL is reachable only from the API host, over TLS, with the certificate and hostname verification Ekklesia already requires.

Rate limiting is per-process today

Better Auth's authentication rate limiter is in-memory and per API process. That is acceptable only while both of the following hold, which is the current state:

• production public signup is disabled (and cannot be enabled — see above); and
• exactly one API instance serves traffic.

If either changes — public signup is enabled, or a second instance is added — a durable shared or edge rate limiter becomes mandatory, and it must be proven that its counters are shared across instances, survive process restart, and cannot be re-bucketed by a spoofed client-IP header. Ekklesia does not ship one. Do not describe the current limiter as distributed throttling.

Continuous integration boundary

CI runs on self-hosted Gitea Actions runners. The inventoried server is Gitea 1.24.2, and that version determines which parts of the workflow are real guarantees and which are not.

The current operating rule: trusted code only

This CI installation is a trusted-code-only boundary. Only code controlled and reviewed by trusted repository collaborators may execute on the self-hosted runner. An unknown or untrusted pull request must not execute on it automatically — a maintainer reviews the diff, including any change to the workflow itself, before it runs.

This is an operating rule, not an enforced technical control, and it is the reason the rest of this section is safe today. Everything below describes what the repository can and cannot prove about that runner; none of it is a substitute for the rule.

What is true of the repository today

These are properties of files in this repository, enforced by the action or the package manager, independent of server version:

• every action reference is pinned by a full immutable commit SHA;
• dependencies install with pnpm install --frozen-lockfile;
• there is no pull_request_target workflow;
• no repository, organization, or instance secret is referenced anywhere in the workflow;
• every checkout step sets persist-credentials: false;
• the workflow declares permissions: contents: read.

What persist-credentials: false actually proves

It proves exactly one thing: actions/checkout does not write its credential into .git/config, so a later step in the same job cannot read or reuse it from there.

It does not remove the short-lived GITEA_TOKEN from the job environment, and it does not reduce that token's server-side authority. A step that wants the token can still read it.

What Gitea 1.24 ignores — so the branch cannot claim it

Per the official comparison for this version (https://docs.gitea.com/1.24/usage/actions/comparison), Gitea 1.24's unsupported workflow syntax includes permissions and jobs.<job_id>.permissions, concurrency, and jobs.<job_id>.timeout-minutes. On this server those declarations are inert. Therefore:

• The workflow's permissions: contents: read does not restrict the job token. This branch cannot claim the GITEA_TOKEN is read-only, because nothing in workflow YAML makes it so on 1.24. Job-token permission controls, repository/owner defaults, and server-side maximum-permission clamping arrive in the 1.26 feature line (https://docs.gitea.com/1.26/usage/actions/token-permissions).
• concurrency and timeout-minutes are not bounded-execution guarantees here. Cancellation, timeout, and teardown must be enforced by a trusted provisioner and reaper outside the workflow.

The declarations are kept deliberately: they are already correct for a supported Gitea release and for GitHub Actions, and keeping them means the upgrade does not require re-deriving the intent. They are documented as ignored, not removed.

Runner topology is not verified

The runner topology is not verified in this repository and is not documented here as though it were. A pull request can edit runs-on and select any runner label its repository can reach, so a workflow file cannot be the boundary. Whether untrusted pull-request jobs execute on a disposable guest, and whether any runner reachable from this repository holds deployment authority or a host Docker socket, must be established against the actual Gitea instance and runner hosts. Until that evidence exists, treat pull-request CI as executing with whatever authority the runner host actually grants.

Requirements before executing untrusted contributions

These five items are the prerequisites for relaxing the trusted-code-only rule above — that is, for letting code this project has not reviewed execute on this Gitea installation. They are backlog requirements for that specific future capability. They do not block Phase 6 Surface work, and they are not conditions on merging trusted, reviewed work.

None of them can be satisfied by editing this repository; each requires access to the Gitea server and runner hosts, and each must be proven there.

1. Upgrade Gitea to a reviewed supported release with job-token permission controls — at least the 1.26 feature line. Select the actual release during infrastructure work, after backup and compatibility review; do not pin a version from this document.
2. Configure repository and owner defaults, and the server-side maximum permission, so workflow code cannot request more than read-only repository access.
3. Prove against the real server that the job's GITEA_TOKEN cannot push code, create or update releases, packages, issues, or pull requests, change Actions configuration, or reach another private repository.
4. Enforce job timeout, cancellation, concurrency, and teardown in the trusted provisioner/reaper rather than relying on the ignored workflow keys above.
5. Complete a disposable-guest runner isolation proof: one throwaway guest per job, torn down by a trusted reaper outside workflow YAML, holding no deployment credential, registration token, or reusable key.

Moving future public contribution workflows to a service that provides isolated hosted runners — for example GitHub — is an accepted alternative to satisfying items 1–5 on this installation.