feat(security): opt-in flag for local-network-access delegation to editor iframes

[jannefleischer]

Context

Companion to Euro-Office/web-apps#276, Euro-Office/sdkjs#95, Euro-Office/DocumentServer#399 and Euro-Office/documentation#21. While testing an AI plugin whose provider requests run as a browser fetch() from the editor to a private-network host (an internal Ollama instance), the request was silently blocked by the browser's Local Network Access checks, because the local-network-access/loopback-network Permissions Policy feature was not delegated through the editor/plugin iframe chain.

As discussed in Euro-Office/web-apps#276, delegating this unconditionally is an unwanted security risk in many business setups. It has to be an explicit opt-in by the operator.

Change

• New config key security.allowLocalNetworkAccessIframes (default false) in Common/config/default.json.
• DocsCoServer.js reads it via ctx.getCfg (so it is tenant-overridable like other settings) and sends it as allowLocalNetworkAccess in the license message, next to aiPluginSettings.

sdkjs (#95) and web-apps (#276) only add the allow tokens to the plugin iframes when this flag is true. Default behaviour is unchanged.

Enabling

NODE_CONFIG='{"security":{"allowLocalNetworkAccessIframes":true}}'

With the Docker image: -e ALLOW_LOCAL_NETWORK_ACCESS_IFRAMES=true (Euro-Office/DocumentServer#399, standalone and orchestrated entrypoints). Documented in Euro-Office/documentation#21.

Caveats

This is the single switch for the operator. The outer editor iframe (created by the integrator page via api.js before the editor talks to the server) always delegates the feature; that alone grants nothing, because the browser requires delegation through every frame in the chain and the plugin iframes only delegate when this flag is set. So connectors (Nextcloud, Seafile, …) need no changes. See web-apps#276 for details.

Effective in Chromium-based browsers and Firefox ≥ 153, which gate local network access on the same local-network/loopback-network Permissions Policy features; Safari/WebKit is still implementing it (see web-apps#276).

Draft until the maintainers agree on the approach in web-apps#276.

AI-assisted; disclosed per the AI Contribution Policy.