[tor-onions] Onion-routing of The Free Software Foundation Europe

[Silvia/Hiro]

Hi Jacob,

On 2021-01-22 12:21, Jacob Hrbek wrote:
> On 1/21/21 9:27 PM, Silvia wrote:
>> Exciting to see fsfe moving to onions.
>> How can we help you guys with this?
> 
> Currently the main problem is with implementation as there is an issue 
> with certificates using TLS-over-onions (Not economical for non-profit 
> foundation) where it seems that using reverse proxy with currently used 
> Apache or implementing EOTK is the way to go there? 


Yes EOTK uses a TLS certificate. The idea behind this is that if the
certificate belongs to fsfe, visitors of the onion service can be sure
that the onion has been setup by fsfe.
The certificate is not needed for any other reason than that.

If you are concerned about how people discover your onion you can use
the onion-location header so that people visting fsfe.org over tor get
the onion available button on the url bar and can get redirected to the
onion
(https://community.torproject.org/onion-services/advanced/onion-location/).

> More options and way 
> to configure EOTK (alec seems to be currently busy and unable to answer) 
> appreciated.

EOTK is a tool that setup a few options for you in nginx and install
required packages, but you can setup the onion also manually.
Here for example you will find a gist of the nginx config of the
propubblica onion:
https://gist.github.com/mtigas/9a7425dfdacda15790b2

> 
> Also brainstorm for the implementation as a whole would be appreciated 
> the services seems to be mostly running in jail/VM which is favorable to 
> be preserved for security reasons (e.g. in scenario where there is a 
> major bug discovered in the wild to reduce the impact of one service on 
> the system).
> So i am currently unsure whether we want to:
> 1. run one tor daemon per system in jail/VM to provide the routing from 
> exposed ports from the services e.g. 
> https://git.fsfe.org/kreyren/fsfe-planet/src/branch/onionz/docker-compose.yml
> 2. implementing tor daemon within these jails/VMs with the service
> 
> srv/service1 (exposing port 12447)
> srv/service2 (exposing port 12448)
> 
> and setting tor as
> 
> HiddenServiceDir /var/lib/tor/service1
> HiddenServicePort 12447 127.0.0.1:12447
> 
> HiddenServiceDir /var/lib/tor/service2
> HiddenServicePort 12447 127.0.0.1:12447
> 
> 

I am not sure about the exact architecture here, but generally you need
a master onion where you run onion balance and use it to scale
horizontally with different backends
(https://onionbalance-v3.readthedocs.io/en/latest/v3/tutorial-v3.html).

If you are concerned about DOS attacks you can also implement some more
advanced web server configs.
One of them is using captchas, another is to use cookies to filter out
scripted clients. The idea in this case is that the web server sends the
client a cookie and ask the client to verify it. Usually scripted
clients don't set cookies so the verify fails and you find out that the
client is malicious.

Nginx uses openresty and lua to implement captchas. This solution is
usually highly scripted. With regards to cookies I can recommend this
library from cloudflare for openresty
https://github.com/cloudflare/lua-resty-cookie. I am sure there are
equivalent solution in apache.


> 3. implementing tor daemon on the router assuming all services being 
> routed through a routing server, but i am concerned about sanitization 
> as if there is a bug in tor that could expose user traffic to bad 
> actors. (currently being discussed)
> 
> 4. Implementing xen (https://en.wikipedia.org/wiki/Xen) which currently 
> not favorable as it would require lots of work on the backend.
> 
> 5. Other?

There is a tool called onionscan (https://onionscan.org/) that can help
you find vulnerabilities on your onion. This also test things like bugs
in your web service that might expose users data and information that
you might prefer to keep secure.

I also assume that the fsfe onion isn't interested to be anonymous so
you might consider setting up a 1-hop onion in this case
(https://support.torproject.org/glossary/single-onion-service/).

Let me know if you need more help.

Cheers,
-hiro
> 
> FWIW i would also like to provide something like 
> https://onion.debian.org so that the website list is available to the 
> end-user.
> 
> 
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