111 lines
4.4 KiB
Markdown
111 lines
4.4 KiB
Markdown
malcontent
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==========
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malcontent implements support for restricting the type of content accessible to
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non-administrator accounts on a Linux system. Typically, when this is
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used, a non-administrator account will be for a child using the system; and the
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administrator accounts will be for the parents; and the content being filtered
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will be apps which are not suitable for the child to use, due to (for example)
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being too violent.
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It provides an
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[accounts-service](https://gitlab.freedesktop.org/accountsservice/accountsservice)
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vendor extension for storing an app filter to
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restrict the child’s access to certain applications; a simple library for
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accessing and applying the app filter; and a UI program (`malcontent-control`)
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for viewing and changing the parental controls settings on users.
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The parental controls policy is stored in `/var/lib/AccountsService/users/${user}`,
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which is a key file readable and writable only by the accounts-service daemon.
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Access to the data is mediated through accounts-service’s D-Bus interface, which
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libmalcontent is a client library for.
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All the library APIs are currently unstable and are likely to change wildly.
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Two kinds of policy are currently supported:
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* A filter specifying whether installed applications are allowed to be run;
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this is typically set up to restrict access to a limited set of
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already-installed applications — but it can be set up to only allow access
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to a fixed list of applications and deny access to all others.
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Applications which are not currently installed are not subject to this
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filter.
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* A set of mappings from [OARS categories](https://hughsie.github.io/oars/) to
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the maximum ratings for those categories which are permissible for a user to
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install apps with. For example, a mapping of `violence-realistic=mild` would
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prevent any applications containing more than ‘mild’ violence from being
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installed. Applications which are already installed are not subject to this
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filter.
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Additional policies may be added in future, such as filtering by content type
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or limiting the amount of time a user is allowed to use the system for.
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Any application or service which provides the user with access to content which
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should be parentally filtered is responsible for querying the user’s parental
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controls filter and refusing to provide the content if not permitted by the
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filter. This could mean refusing to launch a flatpak app, hiding a search
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result in gnome-shell, or hiding an app in gnome-software because of its high
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OARS rating.
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A sufficiently technically advanced user may always work around these parental
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controls. malcontent is not a mandatory access control (MAC) system like
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AppArmor or SELinux. However, its correct use by applications should provide
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enough of an obstacle to prevent users easily or accidentally having access to
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content which they shouldn’t.
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Example usage
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---
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malcontent ships a `malcontent-client` application which can be used to get and
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set parental controls policies for users.
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```
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$ # This sets the parental controls policy for user ‘philip’ to allow no \\
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installation of apps with anything more than ‘none’ for realistic violence, \\
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and to blacklist running the org.freedesktop.Bustle flatpak:
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$ malcontent-client set philip \\
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violence-realistic=none \\
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app/org.freedesktop.Bustle/x86_64/stable
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App filter for user 1000 set
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```
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With that policy in place, other applications which are aware of malcontent will
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apply the policy:
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```
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$ flatpak run org.freedesktop.Bustle
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error: Running app/org.freedesktop.Bustle/x86_64/stable is not allowed by the policy set by your administrator
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```
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Development
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-----------
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When developing malcontent, you should be able to run an uninstalled version of
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`malcontent-client` or `malcontent-control`, as long as the polkit files from
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`accounts-service/` and `malcontent-control/org.freedesktop.MalcontentControl.policy.in`
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have been installed system-wide (typically under `/usr/share/polkit-1`) where
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your system copy of polkitd can find them.
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Dependencies
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------------
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* accounts-service
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* dbus-daemon
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* flatpak
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* gio-2.0 ≥ 2.60
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* gio-unix-2.0 ≥ 2.60
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* glib-2.0 ≥ 2.60
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* gobject-2.0 ≥ 2.60
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* gtk+-3.0
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* polkit-gobject-1
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Licensing
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---------
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All code in this project is licensed under LGPL-2.1+. See COPYING for more details.
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Bugs
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----
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Bug reports and patches should be filed in
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[GitLab](https://gitlab.freedesktop.org/pwithnall/malcontent).
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