Security

3MF Library is made to run at home and be reachable from outside through a reverse proxy. These are the rules it follows.

Your files

• The library is mounted read-only. The site has no way to change, move or delete your files.
• Only files that are in the index can be downloaded; paths are checked so nothing outside the library is reachable.
• Descriptions from 3MF files are cleaned of scripts and styling before they’re shown; the site’s strict content security policy allows no inline scripts at all.

Logins

• Everything needs a login, except the login and setup pages, the site’s own styling and scripts, /health, and slicer links (which carry their own token).
• Home network: a visitor that reaches the site directly from TRUSTED_NETWORKS is let in without a login. Any request that comes through a proxy (or carries forwarding headers, or comes from a KNOWN_PROXIES address) never counts as home network, whatever it claims.
• First account: only while there are no accounts, never through a proxy, and either from the home network or with the one-time setup code from the container log.
• Passwords are stored as salted hashes (ASP.NET Core Identity’s hasher). Admin rights are checked in the database on every request, so taking them away works immediately.
• Changing or resetting a password ends that account’s other sessions.
• Logins, setup and password changes are rate-limited: 8 attempts per 5 minutes per address (logins) or per account (password changes).

Proxies

X-Forwarded-For and X-Forwarded-Proto are only believed from addresses in KNOWN_PROXIES. Without it they’re ignored, so a visitor can’t fake their address to dodge the rate limit or look like the home network.

Slicer links

“Open in your slicer” hands the slicer a link to one file, valid for 15 minutes, signed with the site’s key. Anyone with that link can download that file during those minutes (that’s how the slicer gets it without your login); it gives access to nothing else.

Previews and caching

Previews, photos and 3D meshes are sent with Cache-Control: private, so a shared proxy cache never keeps them. Turn off asset caching in your proxy anyway.

The container

The image runs as an unprivileged user with a read-only root file system, no Linux capabilities and no-new-privileges, and only ./data is writable. A memory cap keeps one huge model from affecting the rest of the machine.

Reporting a problem

Found a security issue? Please report it privately through GitHub’s security advisories instead of a public issue.