This is a project designed to be an example for SGX program to behave differently according to command line parameters.

There's a server and a client connected with socket. Upon the connection sucessfully built, they agree with a session key with Diffie–Hellman Protocol. After that, the server acts as a echo server and repeats whatever the client says. Users can type in any message from keyboard to the client side, and see server's reply on the screen.

1. Build

   # Build in Hardware Mode
   $ make
   
   # Build in Simulation Mode
   $ make SGX_MODE=SIM

   Note: If failed due to SDK location problem, build with this command

   # Build by specifiying SDK directory
   $ make SGX_SDK=<path_to_sgxsdk_directory>

2. Run a server

   $ ./app s 5000

   Note: If failed due to library path issue, execute this command before run the server

   $ export LD_LIBRARY_PATH=<path_to_linux-sgx/build/linux>:$LD_LIBRARY_PATH

3. Run a client

   $ ./app c localhost 5000

   Note: If failed due to library path issue, execute this command before run the client

   $ export LD_LIBRARY_PATH=<path_to_linux-sgx/build/linux>:$LD_LIBRARY_PATH

There's a significant flaw in the program. In the project, client and server agree with a shared key using the simplest version of Diffie-Hellman Key Exchange Protocol. Document suggests that we should always hold dh_msg buffer in enclave space, but we didn't. So it will be trivial for malicious Operating System to conduct a MiTM attack.

To excellent code base from http://csapp.cs.cmu.edu/3e/code.html. I used it to build socket server and client.