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diff --git a/README.md b/README.md new file mode 100644 index 0000000..c7fe43d --- /dev/null +++ b/README.md @@ -0,0 +1,92 @@ +# firefox-profiles + +This repository attempts to provide tooling to aid the configuration of Firefox, +and offers multiple profiles which sacrifice convenience and sometimes security +in favor of data frugality. + +## Required tooling + +- [Nix](https://nixos.org/nix/), which offers a very convenient way of working with + deeply nested attribute sets, including composing and generating them. + + - Nix is used here to build the Firefox configuration, to bundle it with nixpkgs-provided Firefox, + and to provide a wrapper to quickly test configuration changes with temporary profiles. + A deployment path without the installation of Nix on the managed devices is plausible, + only the administrator will need to have it installed. + +## Usage + +```bash +# this launches a configured instance +$(nix-build --no-out-link -A launcher)/bin/firefox +``` + +## Configuration approach + +Firefox exposes two different types of settings: + +- [*Preferences*](https://developer.mozilla.org/en-US/docs/Mozilla/Preferences/A_brief_guide_to_Mozilla_preferences): Key value pairs, e.g. `browser.cache.disk.enable` or `browser.search.defaultenginename` + - These are inspectable by visiting `about:config` + - I don't expect a lot of interface stability here + +- [Enterprise policies](https://github.com/mozilla/policy-templates/) + - [Via `org.mozilla.firefox.plist` for macOS](https://support.mozilla.org/en-US/kb/customizing-firefox-macos-using-configuration-prof) + - [Via AD and "Local Group Policy" for Windows](https://support.mozilla.org/en-US/kb/customizing-firefox-using-group-policy-windows) + - [Using `policies.json` as the only cross-platform method](https://support.mozilla.org/en-US/kb/customizing-firefox-using-policiesjson) + - Despite the warning, they seem intended to be a more stable interface + - They offer limited access to the key value pairs mentioned above, exposing + a subset of them as [Preferences](https://github.com/mozilla/policy-templates/#preferences) + +As far as I can tell, the primary methods of configuration are: + +- The Firefox profile, stored in **~/.mozilla/firefox/something.default** + - **prefs.js**: This file contains interactively set configuration variables. + It is overwritten frequently and should not be modified from applications that + are not Firefox. + - **user.js**: A configuration file similar to `prefs.js`, but it is never written + to by Firefox, and is loaded after `prefs.js`, which means preferences defined + here take precedence. + +- The Firefox distribution, created either by Mozilla directly, or by your + favorite Linux distribution package maintainers + - `$FIREFOX_EXECUTABLE/../lib/firefox/distribution/policies.json`: Allows defining enterprise policy settings, + which are applied to any instance launched from `$FIREFOX_EXECUTABLE`. + - `$FIREFOX_EXECUTABLE/../lib/firefox/defaults/pref/*.js`: These files are executed on every launch, and can + serve as an alternative to `user.js` + - `$FIREFOX_EXECUTABLE/../lib/firefox/browser/omni.ja`: Contains bundled resources and scripts, which are given + special permissions in some situations (e.g. pre-configuring a default search engine). + +For this project, I decided against `user.js` for the following reasons: + +- It's not recommended by Mozilla, I've seen enterprise policies recommended more often for shipping + preconfigured instances. +- Preconfiguration via `user.js` would require copying into every profile of every user it should apply to, + which requires either a wrapper script or a daemon to watch for new profile creations. +- The `user.js` files in the users profile directory are editable by users, and every process they execute. + This can be exploited to e.g. configure a socks proxy and spy on users without their knowledge. +- [Future support for configuration via user.js is uncertain](https://bugzilla.mozilla.org/show_bug.cgi?id=1543752) +- Installation-wide configuration should happen centrally, not in a dozen places all over /home. + +Meanwhile, enterprise policies seem to enjoy more direct support from Mozilla, are applied to any profile launched +with the bundled Firefox, and the bundled preference files are not editable by ordinary user processes. + +Depending on the selected profiles, a combination of enterprise profiles, a bundled settings file in `lib/firefox/defaults/pref/*.js`, +and even patching of `omni.ja` is applied in order to achieve their goal. + +## Qwant Junior + +I built a minimal extension to add Qwant Junior as a search engine in `profiles/addons/qwantjunior`. + +Mozilla tried very hard to prevent the preconfiguration of bundled default search engines, and the only way +to do so (as far as I could tell), is to install the extension into FFs built-in extensions. Being a built-in +extension bypasses the prompt asking the user whether to allow setting a default search engine. + +The extension works Fine™ if installed ordinarily, but it prompts the user with a dialog on the first start, +which had a bug in my testing, and I needed to be careful to prevent accidental dismissal. + +And yes, Firefox refuses to load the addon if the id doesn't match `*@search.mozilla.org`. + +## Known issues + +- With this first attempt, usage errors can be silently ignored, which is probably going to be quite irritating for any non-Nix people. + - I plan to migrate this to Nix modules, which should result in a much better configuration exprience. |