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Secure Network Interface with SGX

This repo provides network security functionality within an Intel SGX enclave. The documentation provides a short overview of the functionality. My master thesis contains technical details and background information.

Build Setup (Simulation Mode):

:warning: Warning: The build-instructions in this repo might be outdated. Please do not rely on those build-instructions and refer to official Intel-instructions instead. This has been only tested with Ubuntu 18.04.

Install the packages:
make cmake git g++ cppcheck
ocaml ocamlbuild automake autoconf libtool wget python libssl-dev

Download, build and install the linux-sgx sdk:
git clone https://github.com/intel/linux-sgx.git
cd linux-sgx
./download_prebuilt.sh
make sdk
cd linux/installer/bin
./build-installpkg.sh sdk
./sgx_linux_x64_sdk_XXX.bin # install in "~" when asked

Build and run the tests:

./run_tests_locally.sh SIM

Build Setup (Hardware Mode):

Please complete the simulation mode instructions before setting up the hardware mode. Hardware mode works only on SGX-supported platforms.

Configure your system to SGX enabled. You might need to enable SGX within your BIOS settings.

Build and install the SGX Driver according to the instructions in https://github.com/intel/linux-sgx-driver.
Afterwards, check whether the SGX Driver is running: lsmod | grep isgx

Install the packages:
libprotobuf-dev protobuf-compiler libcurl4-openssl-dev

Build and install the SGX Platform Service:
cd linux-sgx
make
cd linux/installer/bin
./build-installpkg.sh psw
sudo ./sgx_linux_x64_psw_XXX.bin

Build and run the tests:

git clean -xfd # cleanup for a fresh build
./run_tests_locally.sh HW

Future work:

Implementing those protocol validations in C is a bad idea with respect to security. The choice of the C Programming Language was only made because the Rust-SGX-support was still in its early stages at the time of writing. Therefore, I strongly recommend that future TEE implementations use a secure language from the beginning (e.g. Rust, Go, Kotlin).

More generally, given todays knowledge and research advancements, the usage of C for security-critical systems is a huge mistake. Unfortunately, this is the security-world that we have in 2020. Large systems like the Linux-kernel cannot be rewritten at once, but they need to be rewritten in a gradual manner.

Nevertheless, the usage of C can still be acceptable for safety-critical systems. In this context, please be careful to correctly distinguish between security-critical systems (e.g. a parsing-library) and safety-critical systems (e.g. a flight control computer).

Limitations of SGX: Currently, SGX cannot directly access any external hardware. Therefore, it is necessary to establish a cryptographic channel to securely communicate between an SGX enclave and external hardware. In this work, we used a "MACSec gateway" for this cryptographic channel. Other TEEs can be configured to avoid this issue altogether (e.g. ARM TrustZone).