Sandboxing

Scripts, files and tools related to sandboxing

Description

This sandboxing suite primarily targets desktop use, but may include assets for server use

The scripts and files in this repo are designed to be readily usable on most systems

• You only have to install OCaml toolchain if you want to develop upon the generator

Basics

• Private home for programs
• Shell interpreter access is removed in the sandbox
• Access to number of binaries is minimized (via bubblewrap and AppArmor)
• Fairly strict seccomp filters are supplied to bubblewrap
• Fairly strict AppArmor profiles are generated

Note that some profiles assume usage of Wayland

Install

Simply git clone https://github.com/darrenldl/sandboxing.git in home

Your system needs to have bubblewrap, gcc and apparmor to run the scripts

Installation

Important: Please make sure the following directories are not already in use in your $HOME

• sandboxing/
• sandboxes/
• sandbox-logs/

All bash scripts in scripts/ directory should work out of the box on most Linux distros

The scripts assume they stay in their original positions in the local copy of the repository, however

One can invoke them via the full path

./sandboxing/scripts/firefox.sh &

or use add_links.sh DEST to create symlinks to the scripts

./sandboxing/add_links.sh ~/.bin # say ~/.bin is in our PATH variable
sandbox-firefox-private &        # all symlinks are prefixed with "sandbox-" to allow easy removal
                                 # and avoid shadowing

General usage

Invoke the script directly (or via symlink), stdout are stored as ~/sandboxing-sandbox-logs/profile/*.stdout, stderr are stored as ~/sandboxing-sandbox-logs/profile/*.stderr

See the following section for profile specific usage

Profiles

Only the listed profiles are considered stable

Following serves as rough descriptions only, check the scripts directly to see if they fit your needs

Internet

• firefox
  • Persistent home as ~/sandboxing-sandboxes/firefox on host
• firefox-tmp
  • No persistent home
  • Temporary persistent Downloads folder in sandbox home, created as temporary directory under /tmp on host
    • This is the only directory that host and sandbox share
  • Is NOT hardened against tracking/fingerprinting
• firefox-private
  • Same as firefox-tmp, but uses the hardened user.js transparently (should work on most Linux distros)
  • Important: Please check the user.js is indeed loaded correctly, see https://github.com/pyllyukko/user.js/#verifying for how to verify
• thunderbird
  • Persistent home as ~/sandboxing-sandboxes/thunderbird on host
• discord
  • Persistent home as ~/sandboxing-sandboxes/discord on host
  • AppArmor profile not usable yet

PDF reading

• okular-ro

  • No persistent home
  • Accepts exactly one argument for file to be read, e.g. sandbox-okular-ro file.pdf
  • RO mounts only the specified PDF file in sandbox home
  • No network access

• okular-rw

  • No persistent home
  • Accepts exactly one argument for file to be read, e.g. sandbox-okular-rw file.pdf
  • RW mounts only the specified PDF file in sandbox home
  • No network access

Image viewing

• eom-ro
  • No persistent home
  • Accepts exactly one argument for file to be read, e.g. sandbox-eom-ro file.png
  • RO mounts only the specified file in sandbox home
  • No network access

Development

TODO

• Make each sandbox use a separate user (not sure yet)

• Transition to syscall whitelist instead of blacklist

• Network namespace set up with routing and DNS

WIP

• Discord AppArmor profile

Index

• aa-profiles/ contains the generated AppArmor profiles
• firefox-hardening/ contains files specific to Firefox
• gen/ contains the OCaml code responsible for generating the bubblewrap scripts and generating seccomp BPF generator C code
• runners/ contains the generated runner C code
• scripts/ contains the generated bubblewrap scripts
• seccomp-bpfs/ contains the generated seccomp BPF generator C code

See gen/src/profiles.ml for existing profiles

Run make run in bw-script-gen/ to generate scripts after making updates to the profiles

Acknowledgements

Some components (e.g. bubblewrap scripts, seccomp filter blacklist) are based on the following repo

• https://github.com/valoq/bwscripts

AppArmor profile generation, seccomp filter whitelist, and other design choices are based on the following repo

• https://github.com/Whonix/sandbox-app-launcher

Files in firefox-hardening/ are from the following repo

• https://github.com/pyllyukko/user.js/