helloc++

How to create a C++ Marble

This example shows how to build a confidential C++ application and run it in MarbleRun. This can serve you as a blueprint for making existing applications MarbleRun-ready or creating new Marbles. If you haven't already, setup MarbleRun to get ready.

Note: You can run this example on any hardware by simulating the enclave through setting OE_SIMULATION=1 as environment variable. This might help you to get started with the development of confidential apps. However, please notice that this bypasses any security. Detailed information on how to develop secure Marbles can be found in MarbleRun's documentation.

The directory app contains the application code:

• hello.cpp: constitutes the actual program.
• CMakeLists.txt: Compiles the program into the static library libapp.a.

You can build the example as follows:

mkdir build
cd build
cmake ..
make

Then get the enclave's unique ID aka MRENCLAVE

oesign dump -e enclave.signed | grep mrenclave

and set it as UniqueID in manifest.json.

Next, use the erthost command to start the Coordinator in a local enclave:

erthost ../../../build/coordinator-enclave.signed

The Coordinator exposes two APIs, a client REST API (port 4433) and a mesh API (port 2001). While the Coordinator and your Marble communicate via the mesh API, you can administrate the Coordinator via the REST API.

Once the Coordinator instance is running, you can upload the manifest to the Coordinator's client API:

curl -k --data-binary @../manifest.json https://localhost:4433/manifest

To run the application, you need to set some environment variables. The type of the Marble is defined in the manifest.json. In this example, the manifest defines a single Marble, which is called "hello". The Marble's DNS name and the Coordinator's address are used to establish a connection between the Coordinator's mesh API and the Marble. Further, the UUID file stores a unique ID that enables a restart of the application.

EDG_MARBLE_TYPE=hello \
EDG_MARBLE_COORDINATOR_ADDR=localhost:2001 \
EDG_MARBLE_UUID_FILE=$PWD/uuid \
EDG_MARBLE_DNS_NAMES=localhost \
erthost enclave.signed

The app prints a "Hello world!" followed by the command line arguments that are defined in the manifest.json.