Saint SmashEx, Who Broke Into the Enclave

Patron of SGX enclaves, exception handling, and everyone who thought the processor's vault was inviolable.

Life

On 16 November 2021 a group of researchers presented SmashEx: an SGX enclave, the sealed vault inside the processor, could be interrupted by an asynchronous exception just while it was in a fragile state. Re-entering during that instant corrupted the enclave's stack and ran code inside it, breaking its confidentiality and integrity. It affected several runtimes, Microsoft's Open Enclave SDK among them, which fixed the exception handling (CVE-2021-33767).

Prayer

O Saint SmashEx, who knocks at the enclave in its weakest moment, let our vault not open the door mid-gesture. Amen.

How to celebrate

Celebrated by updating the SGX runtimes and making exception-handling re-entry safe.

Interrupt at the right moment and you enter where none may.