Why TEE Developers Are Replacing Heap Allocation with Bump Buffers for Security

Developers building high-assurance Trusted Execution Environments (TEEs) face serious security risks from standard heap allocation, including timing side-channels, memory fragmentation, and an expanded Trusted Computing Base (TCB). In the sakshi-core attestation loop of the Sovereign Spine architecture, standard global heap allocation was replaced with a session-scoped bump buffer to enforce deterministic memory behavior. The bump buffer model allocates memory via a simple pointer increment in constant time and clears it atomically at the end of each session, eliminating fragmentation entirely. This approach reduces enclave memory logic to a small, auditable block of code rather than thousands of lines introduced by a global allocator. The implementation is available as part of the sakshi-core module in the open Citadel Protocol repository.