View article

In this paper, we present HYPERRACE, an LLVM-based tool for instrumenting SGX enclave programs to eradicate all side-channel threats due to Hyper-Threading. HYPERRACE creates a shadow thread for each enclave thread and asks the underlying untrusted operating system to schedule both threads on the same physical core whenever enclave code is invoked, so that Hyper-Threading side channels are closed completely. Without placing additional trust in the operating system's CPU scheduler, HYPERRACE conducts a physical-core co-location test: it first constructs a communication channel between the threads using a shared variable inside the enclave and then measures the communication speed to verify that the communication indeed takes place in the shared L1 data cache-a strong indicator of physical-core co-location. The key novelty of the work is the measurement of communication speed without …