[Noisebridge-discuss] Tor/Cypherpunk hack day at Noisebridge?

Mike Perry mikeperry at torproject.org
Tue Aug 16 20:38:03 UTC 2016

Hey Noisebridgers,

I've been out of orbit for a looong time, but I've been observing your
earth, and I would like to make a contact with you[1].

I've been talking to Patrick O'Doherty and he suggested it would be good
to try to set up some kind of regular Tor and/or general cypherpunk
meetings or hack days at Noisebridge. I have a pile of projects I'm
working on that may be interesting to folks, and I can also help get
people up to speed with Tor development and build processes, how to
write patches, and familiarize people with Tor codebases and Tor
functionality for use in their own projects.

This is a long email. The TL;DR is that I'm looking for people to tell
me what sort of stuff they would be interested in working on or learning
about at these meetings, so I can try to serve that audience better and
keep things focused.

I'm giving a ton of detailed examples based on stuff I've been hacking
on on the side. Let me know either on or off-list if you find any of
these projects interesting and would like to work on any of them. Please
also suggest your own projects/ideas on-list, and please also +1 other's
topics as well.

I'm hoping that the projects we work on can be featured on Tor Labs,
which is a website we're launching that is meant to showcase prototypes
and external projects that make interesting use of Tor, or that may
otherwise be of interest to Tor hobbyists. Tor has a lot of eyes on it,
and I think we should make use of that attention to get more people
excited about the great work that folks do outside of the official Tor

Here's some of the stuff I've been working on:

# A Tor Phone prototype based on CopperHeadOS

Since I wrote my writeup of a prototype Tor/Cypherpunk/Wingnut Phone[2],
a lot of cool stuff has been done by volunteers and the wider Android
community. C├ędric Jeanneret adapted my pile of half-insane Droidwall
hacks into the rather slick OrWall[3], Patrick Connolly transformed the
manual install process into an update.zip[4], and some Toronto hackers
created CopperHeadOS[5] - a hardened Android rebuild using grsec and
several hardening additions, including verified boot[6].

Unfortunately, CopperHeadOS does not support Google Apps, MicroG[7] (the
FLOSS replacement for Google Services), or SuperUser. You can hack this
stuff in via sideloading, but then you lose verified boot. So I'm
working on a pile of scripts to try to shove this stuff in to the
official CopperHead release images, and re-sign them with new keys. That
way, you don't have to give up security to be able to use apps with Tor,
or to use apps that require Google Play Services (such as Signal).

Ideally, long-term we'd either restrict root access to just OrWall, or
diagnose why the VPN APIs in Android/Orbot leak traffic like crazy (see
below for a fun related router project to help with this).

To work on this project, you'll need a Nexus 9, 5X, or 6P device.

# A udev-based USB firewall

I wrote a crappy pile of shell scripts that act as a USB device ID
(model + serial number) whitelist, to provide vulnerability surface
reduction against USB device driver exploits and attacks like BadUSB.

The scripts work for me, but maybe we should try to make this into a
debian package with easier configuration or something.

# CFC/No More 404s/Resurrect Pages

Cloudflare captchas and Tor bans are annoying, especially if all you
want to do is read something.

Yawning Angel at the Tor Project has been working on a Tor Browser addon
to automatically fetch pages that are blocked by CloudFlare/other
captchas from archive.is/archive.org. It needs a UI and some general
usability improvements:

We could also adapt the official Firefox addons No More 404s or
Resurrect Pages, depending on how they work.

# Better Tor Browser support for SSH exits/private Tor exits

Related to the Captcha and ban problem, I hacked up some prefs and env
vars to make it possible to chain an SSH SOCKS -D proxy after Tor, so
that it is possible to access sites that completely ban Tor with strong
pseudonymity: https://trac.torproject.org/projects/tor/ticket/16917

We could give this thing a UI. As a more involved project, we could
patch Tor to support "Tor Exit Bridges": ie Tor "bridges" that have an
exit policy and can be used instead of public exits.

# OpenWRT-based Tor Firewall

I have a prototype Tor Router based on OpenWRT that only lets Tor
traffic through, and acts as a wifi firewall. It is based on
https://wiki.openwrt.org/toh/tp-link/tl-mr3040, and uses the LEDs to
tell you if anything on your computer has tried to bypass Tor, if
anything on the local network has tried to make a TCP connection to you,
or if anything has sent a ping/UDP packet at you. I've arranged these
LEDs as a sort of "hitpoint" bar, so that the UDP LED is the farthest
out, then the TCP connect-back LED, and then the Tor bypass led is
closest in. It is rather amusing to use this thing at hacker events to
watch how fast stuff happens to you. Since the MR3040 also has an
ethernet jack, you can use it to prevent exposing your laptop's wifi
firmware to hostile networks, by putting the router into client mode and
routing through ethernet. The router firmware supports concurrent client
and host wifi operation, so that you can have the device still provide
firewalling to devices that only support wifi by creating your own
personal access point on one side of the firewall, and acting as a wifi
client on the other.

It is also very useful for helping to debug proper behavior of Tor
applications (especially mobile/embedded apps), so that leaks are
quickly apparent to you.

This device is different than other Tor-enabled routers (such as NetAid
and Anonabox, etc) because it is primarily meant to function as an
additional security layer, not just something that blindly shoves all
your traffic through Tor.

The device has switches on it, so it can be easily switched between
different modes.

Areas of improvement for this project:

 ii). It would be cool to make some kind of REST negotiation API with Tor
      Browser, so that this device could pick bridges or guard nodes for
      Tor Browser, tell Tor Browser about them, and ensure that only
      these bridges or guard nodes were used (as a security layer).

 ii). Various UI work to make it easier to configure through a web UI.
      Maybe borrowing ideas or sharing code with https://netaidkit.net/,
      or maybe just sticking to the OpenWRT UI.

 iii). It might be nice to also have a VPN on here as an option via one of
       the switches, so that traffic that was not destined to Tor was
       VPN'ed instead of dropped. This will require some hacking with
       OpenWRT image creator, since there is not enough space for a VPN in
       the default images for the device.

To work on this project, you will need an OpenWRT compatible router. It
doesn't have to be the MR3040, I just like that one because it has a
battery and LEDs :). If there is enough interest, I can also bring a
pile of old routers I have lying around, as well.

# Reproducible build help with your Tor/Cypherpunk Project

If you're making security tools, build security is very important. I can
help people work towards ensuring their projects can be build
reproducibly. We can also discuss various opsec considerations for
signing key material, and build security for projects that are a long
way away from being able to build reproducibly.

# Your idea here!

Please, suggest stuff you want to work on. Maybe I can help. Or if not,
maybe someone else can!

1. https://www.youtube.com/watch?v=teBV0EoJJY8
2. https://blog.torproject.org/blog/mission-impossible-hardening-android-security-and-privacy
3. https://github.com/EthACKdotOrg/orWall
4. https://github.com/patcon/mission-impossible-android
5. https://copperhead.co/android/
6. https://source.android.com/security/verifiedboot/verified-boot.html
7. https://microg.org/

Mike Perry
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