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Copperhead Tor Phone Prototype

#copperhead on OFTC IRC

The scripts in this directory help you create your own rooted Tor-enabled gapps capable Copperhead image that is signed with your own keys for verified boot.

For more background information, see: https://blog.torproject.org/blog/mission-improbable-hardening-android-security-and-privacy

Compatibility

Only new devices supporting Verified Boot with user-controlled keys are compatible. Additionally, the device has to be supported by Copperhead, and we need an update script directory for updates to work.

Device Installation Updates
Google Nexus 6P
Google Nexus 5X
Google Nexus 9
Everything else

Prerequisites

  • fastboot & adb. You need recent versions from the official command line tools installer. The ones in Debian/stable are sadly too old :(. You can tell if yours is recent enough if fastboot supports the fastboot flashing unlock command.
  • Java JRE/JDK 1.7+
  • git, cpio, gcc, g++
  • openssl development packages. ie. libssl-dev/openssl-devel

Configure udev on your Linux system so you can use fastboot and adb as non-root.

Your phone will need to have OEM Unlocking enabled:

  1. Go to Settings > About Phone.
  2. Tap Build Number five times.
  3. Go to newly created Settings > Developer Options
  4. Enable OEM unlocking

There are some other things, but the scripts will download them.

To ensure the these downloads are fetched via Tor:

torsocks ./run_all.sh

Instructions

It is possible to choose if you want to install Tor, and eventually we want to make it possible to choose if you want Google Apps and/or SuperUser.

To get started run ./run_all.sh -h to see the options. As a bare minimum you must provide a path to th Copperhead image for your device.

The script will walk you through everything, printing out instructions (and command output) as it goes. It will halt on any error, but you can re-run it from the top or run pieces of it individually.

Below is an example for the angler build:

Install

  1. Download your factory image and its signature from the CopperheadOS download page, and place it the git root directory.

    You can use the get-release-image.py script to get the latest image for your your device and to automatically validate the signature, for example:

     $ get-release-image.py angler
    
  2. Run the following:

     $ gpg --recv-keys 65EEFE022108E2B708CBFCF7F9E712E59AF5F22A
     $ gpg angler-factory-2016.10.27.20.13.46.tar.xz.sig
     $ tar -Jxvf angler-factory-2016.10.27.20.13.46.tar.xz
     $ ./run_all.sh angler-nbd90z
    

Note on keys: This installation script will generate device keys in the keys/ directory of the filesystem. You will need these keys to update the phone. Keep them safe, and do not lose them.

Update

  1. Download a new Copperhead image as above.

  2. Prepare your device keys. Make sure they are in the keys/ directory.

  3. Run the following:

     $ gpg angler-factory-2016.10.27.20.13.46.tar.xz.sig
     $ tar -Jxvf angler-factory-2016.10.27.20.13.46.tar.xz
     $ ./update.sh angler-nbd90z angler
    

Binary blobs that run on the host machine

The following is a list of binary blobs we run on your machine during build. (XXX: Find and link to the sources for these).

Binary blobs that run on the phone

  • ./extras/blobs/update-binary
  • ../super-bootimg/scripts/bin/su-arm
  • ./packages/gapps-delta.tar.xz (OpenGapps Pico)

TODOs and Future Work

  • We should probably have a script that does some dependency checking and helps the user install stuff they need to build and install everything.

  • The update process only supports angler (Nexus 6P) right now. Once Copperhead supports the newer Pixel devices, we'll try to add those.

  • We should support the new Nougat FECC layer on top of Verity. Right now, we leave it out. (https://android-developers.blogspot.com/2016/07/strictly-enforced-verified-boot-with.html)

  • If we wanted to support more opengapps than pico, we could generate the gapps file list on the fly.

  • We should build or replace as many of the binary blobs as we can. For some things, this is very tricky, since they have dependencies across the android tree.

  • Instead of OpenGapps, it might be nice to provide the MicroG builds: https://microg.org/. This requires some hackery to spoof the Google Play Service Signature field, though: https://github.com/microg/android_packages_apps_GmsCore/wiki/Signature-Spoofing. Unfortunately, this method creates a permission that any app can request to spoof signatures for any service. I'd be much happier about this if we could find a way for MicroG to be the only app to be able to spoof permissions, and only for the Google services it was replacing.

  • Right now, we require superuser, since the super-bootimg scripts are used to sign the boot partition and ensure verified boot. This is not ideal, since those scripts depend on some binary blobs in that repository (see below), and also because some people might just want Gapps and not Root+Tor.

  • We also need root right now to edit the ext4 images by mounting them. Technically we could use make_ext4fs from the Android build tree, but it requires a block map, file permission lists, and selinux context lists. We would need some other tool to extract (or keep copies of) those..

  • Back in the WhisperCore days, Moxie wrote a Netfilter module using libiptc that enabled apps to edit iptables rules if they had permissions for it. This would eliminate the need for root and crazy iptables shell callouts for using OrWall. This should be more stable and less leaky than the current VPN apis.

Bugs

  1. The swipe keyboard driver is not being recognized by Copperhead's LatinIME package due to the build pref https://github.com/CopperheadOS/platform_packages_inputmethods_LatinIME/blob/marshmallow-mr2-release/java/res/values/gesture-input.xml. We need to do a test build and ensure that flipping that pref won't spam logs, cause issues, or have library search path issues for stock users.

  2. The bootup script stopped working with Orwall 1.2.0. We have to use Orwall 1.1.0. Do not upgrade to 1.2.0 or networking will break.