Please do not report security vulnerabilities in public GitHub issues.

Report them privately through GitHub private vulnerability reporting. Please include:

• the affected component (HAL library, hal-runtime, or a WIT interface) and the commit;
• the platform: AMD SEV-SNP, Intel TDX or non-TEE, plus the cloud provider and kernel version;
• steps to reproduce it, or a proof of concept, and the impact you expect.

We aim to acknowledge reports within 5 working days. We'll agree a disclosure timeline with you, and credit you in the advisory unless you prefer otherwise.

The project is research software developed within the ELASTIC project. Security fixes are made on the main branch only; there are no maintained release branches.

The HAL gives WebAssembly workloads access to platform services inside a Confidential VM: attestation, crypto, storage, sockets, GPU, resources and inter-workload communication. It relies on the following.

• The TEE protects the guest's memory, not the host it runs on. On AMD SEV-SNP and Intel TDX, guest memory is encrypted and integrity-protected against the hypervisor. Disk, network and device I/O leave the guest and are visible to the host, unless the workload protects them itself.
• Wasm isolation separates workloads from each other. A Wasm component can only reach the HAL interfaces linked into its world. The composed worlds in wit-modular/ (minimal, attestation, storage, network, compute) let you grant a workload only the interfaces it needs. The enforcement layer (src/enforcement/), together with the HAL Enforcement Service, adds per-entity capability checks, rate limits and auditing on top.
• The HAL host process is trusted. hal-runtime and the HAL library run with the privileges of the host process. Any workload it loads can use the interfaces that process is able to reach.

Attestation

• The HAL returns attestation evidence: the SNP report or TDX quote, the measurements, and the caller's nonce bound into the report data. It does not verify the hardware signature on that evidence.
• The relying party must verify it:
  • the signature chain (AMD VCEK/ASK/ARK, or Intel PCS/DCAP);
  • that the nonce it sent matches;
  • the measurement and TCB values, against values it expects.

Privileges

• Requesting a report through /sys/kernel/config/tsm/report needs root, because the configfs entries are root-owned.
• Run the HAL with only the privileges it needs. Don't give untrusted users shell access to the host process or its user.

Least privilege for workloads

• Give each workload the smallest WIT world that serves it. For example, use elastic-tee-minimal for crypto-only workloads.
• Use the enforcement layer or the Enforcement Service to restrict capabilities per workload.

Storage

• Objects are written to the guest's file system. hal-runtime uses /tmp/hal-storage.
• Data in unencrypted containers is visible to anyone who can read that disk.
• Keys for encrypted containers are generated in memory and are not persisted. An application that needs its data after a restart must keep the key and load it again with load_object_key.

Network

• Plain TCP and UDP sockets are not encrypted. Protect sensitive traffic at the application layer.
• The TLS support in sockets.rs uses rustls with its default protocol versions (TLS 1.2 and 1.3). The TLS client starts with an empty set of trusted root certificates.

Resource limits

• Each socket uses a file descriptor in the host process. Set ulimit -n to fit the expected number of concurrent connections.
• Use the enforcement layer's rate limits to stop one workload from exhausting shared resources.

Dependencies

• Keep the Rust toolchain and dependencies up to date. Check them regularly with cargo audit.

In scope:

• this repository's code (the HAL library, hal-runtime and the WIT definitions);
• the examples, where they show insecure use of the API.

Out of scope:

• vulnerabilities in the TEE hardware or firmware, the cloud provider's host, the Linux kernel, or third-party crates. Please report these upstream. We'd still like to hear about them if they affect the HAL.