jayo78/bento

Bento is an architecture for adding programmable "middleboxes" to the Tor anonymity network.

Navigation

• bento: source for the client and server packages
• experiments: self contained projects/experiments using Bento
• testing: simple tests and sample functions
• docs: Bento website

Notes:

Tested with python3.6 on Ubuntu 18.04.

Starting a Bento server:

Navigate to bento/server/ and execute:

./runserver.py

Use -h to list the command-line options. By default, the server listens on 0.0.0.0:8888 and runs in the current directory. For storing temporary files, the server creates the directories functions/ and sessions/ if they do not already exist.

Run a sample function as a client:

After starting the Bento server, you can connect to it and test it with the examples in testing/. For instance, execute:

cd testing
./test_hello_world.py   

to run a client that uploads and executes a function that simply sends back "hello world".

Most of the test scripts display a usage statement when passed the -h command-line option.

Writing a function:

A Bento function is a normal Python function that runs on a Bento server. The only difference is that a Bento function executes in an environment that is initialized with a function API (see bento/server/core/api.py) for communicating with the client. In particular, the function must use api.send() and api.recv() to send and receive data from the client, rather than print() and input().

The Bento client API (see bento/client/api.py) provides an RPC interface for uploading, executing, and performing IO with a function.

The scripts and functions in testing/ provide example uses of both the function and client API. You can also use experiments/interactive_client.py to send requests to a Bento server from the command-line.

Connecting the Bento Client with the Bento Server over Tor:

The Bento client API is unaware of Tor. To enable the client to communicate with a Bento server over a Tor circuit, execute the client with the torify wrapper. For instance, to run the test_hello_world.py over Tor, enter:

cd testing/
torify ./test_hello_world.py

torify is a utility that comes with Tor; it uses LD_PRELOAD to encapsulate an application's socket calls in the SOCKS protocol and redirect these calls to a local Onion proxy. In this way, an application can use Tor without having to implement native support for Tor.

Running functions in an SGX enclave:

By default, a Bento server executes functions using the Python3.6 interpreter in the standard, userland environment. To execute functions with the Python interpreter running in an SGX enclave, instead enter:

cd server
./runserver.py -c 'graphene-sgx/pal_loader graphene-sgx/manifest'

The -c option specifies the command the server uses to execute the function. In this example, the command specifies to run the Graphene-SGX library operating system (libOS), and for the libOS to load a Graphene manifest file for Python. See Graphene-SGX for instructions on building the Graphene-SGX library operating system and creating a manifest file.