[Notes] SessionLatch: Attested TLS for Confidential Virtual Machines

Paper

While TLS authenticates a service identity and attestation tells you an environment is approved, clients can’t be certain that the TLS session actually in use terminates in the expected environment. SessionLatch proposes using a trusted observer inside CVMs to prove session-endpoint correspondence.

This observer produces TEE-bound evidence which clients can fetch via a separate control channel as the handshake proceeds, holding (latching) client encrypted records until the evidence verifies and frees up the data path.

The Linux implementation relies on a userspace observer using SOCK_DIAG, nftables/NFQUEUE and other OS facilities. A measured/enforced eBPF or similar kernel mechanism could potentially provide a stronger reference monitor and bind the session to richer workload identity.

More broadly, the paper illustrates why endpoint attestation becomes harder as the TEE boundary expands from process enclaves to entire confidential VMs.