FIPS 140-3

Overview

ocync uses aws-lc-rs as its sole TLS crypto provider. On Linux, binaries link AWS-LC FIPS module 4 by default. AWS has submitted module 4 to NIST and it is in process, awaiting certification.

Build variants

FIPS mode is a compile-time decision. The fips feature flag links the AWS-LC FIPS module. The non-fips feature flag uses aws-lc-rs without it.

A FIPS build restricts TLS to FIPS-approved algorithms: AES-GCM cipher suites, key exchange over P-256, P-384 or the X25519MLKEM768 post-quantum hybrid, and extended master secret for TLS 1.2. ChaCha20-Poly1305 and plain X25519 are never offered. The restriction covers every TLS client in the binary: reqwest, which AWS and Google authentication also use. A FIPS build checks this at startup and refuses to run if TLS is not FIPS-approved.

rustls counts X25519MLKEM768 as approved through its ML-KEM part, although its own source notes that ML-KEM in the AWS-LC FIPS module is FIPS-pending and that it follows the interpretation some regimes (such as FedRAMP Rev. 5 SC-13) allow for modules in that state. Treat the hybrid as approved only if your assessor accepts that interpretation.

FIPS endpoints for ECR

When AWS_USE_FIPS_ENDPOINT=true, ocync rewrites ECR hostnames to use FIPS endpoints:

123456789012.dkr.ecr.us-east-1.amazonaws.com
  -> 123456789012.dkr.ecr-fips.us-east-1.amazonaws.com

With FIPS endpoints, both ends of the connection run FIPS cryptography: the client offers only FIPS-approved algorithms and the endpoint is AWS FIPS-validated. Only ECR has FIPS endpoints among supported registries.

Building with FIPS

FIPS builds require CMake, Go, and Perl for the aws-lc-rs build process:

# FIPS build (default)
cargo build --release

# Non-FIPS build
cargo build --release --no-default-features --features non-fips

Docker images

The latest-fips Docker tag ships the FIPS build:

docker pull public.ecr.aws/clowdhaus/ocync:latest-fips

Verifying FIPS status

The ocync version command reports whether the binary is a FIPS build, the linked cryptographic module, and whether TLS is restricted to FIPS-approved algorithms at runtime:

$ ocync version
ocync 0.9.0
FIPS 140-3: enabled
  module: AWS-LC-FIPS 4
  release: AWS-LC 4.2.0
  tls: approved

module is the AWS-LC-FIPS module number, which is what a NIST validation certificate names. release is the AWS-LC release, which tells builds of one module apart but does not identify a certificate. Non-FIPS builds show FIPS 140-3: disabled and the release. FIPS is a compile-time selection; there is no runtime toggle.

Banned dependencies

ring and native-tls are banned via deny.toml to prevent accidental use of non-aws-lc-rs crypto. reqwest is configured with rustls-no-provider, and the crypto provider is installed explicitly at process startup.