TorBrowserHackingTheNextGeneration

Here are my notes on setting up a build server for Tor Browser hacking! To quote the useful foundation provided here,

 _____ ____  _____ _____   _____ _   _ _____ 
|  ___|  _ \| ____| ____| |_   _| | | | ____|
| |_  | |_) |  _| |  _|     | | | |_| |  _|  
|  _| |  _ <| |___| |___    | | |  _  | |___ 
|_|   |_| \_\_____|_____|   |_| |_| |_|_____|
                                             
 _     ___ _____   _    ____  ____  
| |   |_ _|__  /  / \  |  _ \|  _ \ 
| |    | |  / /  / _ \ | |_) | | | |
| |___ | | / /_ / ___ \|  _ <| |_| |
|_____|___/____/_/   \_\_| \_\____/ 
                                    

Background

Running Debian 10 (buster) on a VPS (I used DigitalOcean for this one). The available memory is important: 16 GB is necessary to build. Below I sometimes do things "in a hurry" by piping curl into a shell, which is Not Good Practice. You should download those scripts, look at them (or ask someone else to look at them, or both), and when satisfied, run them.

Getting the code

• [~10 min] Get the Tor Browser code

  git clone https://git.torproject.org/tor-browser.git

• Fix failed checkout ("warning: remote HEAD refers to nonexistent ref") using version 81 (git branch will show you the version options):

  cd tor-browser
  git checkout remotes/origin/tor-browser-81.0b2-10.0-1

Satisfying dependencies prior to build

• [~15 min] Install stuff we'll need in one fell swoop:

  sudo apt install --no-install-suggests  --no-install-recommends \
      unzip \
      libglib2.0-dev \
      libgconf2-dev \
      libgtk2.0-dev \
      libgtk-3-dev \
      libdbus-1-dev \
      libdbus-glib-1-dev \
      yasm \
      libasound2-dev \
      libcurl4-openssl-dev \
      libxt-dev \
      mesa-common-dev \
      autoconf \
      autoconf2.13 \
      libtool \
      libgstreamer-plugins-base1.0-dev \   
      pkg-config \
      g++ \
      libpulse-dev \
      gnupg \
      curl \
      make \
      software-properties-common \
      zip \
      apt-transport-https

Clone tor-launcher and copy it into place

  git clone https://git.torproject.org/tor-launcher

  mv tor-launcher browser/extensions/

Clone torbutton, and move it into place

  git clone https://git.torproject.org/torbutton

  mv torbutton browser/extensions/

Satisfying Mach

• set up virtualenv

    ./mach create-mach-environment

• install cbindgen. First install rustup via the following (note: apt installing rustc and cargo fails!)

      curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
 then do 
      cargo install cbindgen

• install clang toolchain (oi)

    bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)"
  * symlink clang: 
     ln -s $(which clang-10) /usr/bin/clang
  * symlink clang++: 
     ln -s $(which clang++-10) /usr/bin/clang++
  * symlink llvm: 
     ln -s $(which llvm-config-10) /usr/bin/llvm

• install nodejs 8.11 or newer

    curl -sL https://deb.nodesource.com/setup_lts.x | bash -
    apt install nodejs

• install nasm 2.14 (or better, but we go for the min):

    wget https://www.nasm.us/pub/nasm/releasebuilds/2.14/nasm-2.14.tar.xz
    tar xvf nasm-2.14.tar.xz; cd nasm-2.14
 * open Makefile in nasm directory, remove -Werror=attributes, then 
    configure; make; make install

Generating configure, compiling and packaging

• [~30 min] generate configuration

  ./mach configure \
     --with-tor-browser-version=tbb-nightly \
     --with-distribution-id=org.torproject \
     --enable-update-channel=default \
     --enable-bundled-fonts

• Build

  ./mach build

• Package

  ./mach build stage-package

Getting an existing TBB to serve as a base

• cd $HOME; mkdir tbb-to-copy-over; cd $_

• wget https://www.torproject.org/dist/torbrowser/10.0a6/tor-browser-linux64-10.0a6_en-US.tar.xz

• tar xvf tor-browser-linux64-10.0a6_en-US.tar.xz

• export INSTDIR="$HOME/tbb-to-copy-over/tor-browser_en-US"

• Copy custom stuff onto this base

    cp -a obj-*/dist/firefox/* $INSTDIR/Browser/

Make things smaller

• strip --strip-all $INSTDIR/Browser/*
• rm -f $INSTDIR/Browser/firefox-bin

Get the goodz

Now use rsync or whatever to get tbb-to-copy-over onto your local device.

• rsync -avz --progress name-of-the-tor-build-server-you-set-up:tbb-to-copy-over .