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FIPS 140-3 mode

Added in v1.12.0

Nebula can be built to use the FIPS 140-3 mode of the Go Cryptographic Module (CMVP certificate #5247). In this mode Nebula refuses any algorithm the module does not allow, so only NIST curve P256 and AES-256-GCM can be used.

FIPS 140-3 mode is a build-time choice. The official release binaries are not built this way, so you need to build Nebula from source.

Building

Section titled “Building”

From a checkout of the Nebula source, run one of:

Terminal window
# nebula and nebula-cert for this machine's Linux architecture
make bin-fips140


# release archives for every supported platform
make release-fips140


# any other make target, built in FIPS 140-3 mode
make fips140 <target>

These build against the Go Cryptographic Module v1.0.0 (GOFIPS140=v1.0.0) with the fips140enforce build tag, which enforces FIPS 140-3 mode in nebula, nebula-service, and nebula-cert. release-fips140 builds for the platforms in section 2.2 of the module's security policy: Linux amd64, arm64, arm-7, mips64, and ppc64le, Windows amd64 and arm64, macOS arm64, and FreeBSD amd64.

A FIPS 140-3 build refuses to start unless FIPS 140-3 mode is enforced, so leave GODEBUG=fips140 unset or set it to GODEBUG=fips140=only.

Restrictions

Section titled “Restrictions”

Every host in a FIPS 140-3 deployment needs a P256 certificate, so start by creating a P256 CA:

Terminal window
nebula-cert ca -name "My Org" -curve P256

In a FIPS 140-3 build, nebula-cert ca and nebula-cert keygen default to -curve P256, and refuse -curve 25519. nebula-cert sign refuses to sign with a Curve25519 CA.

nebula refuses to start with a Curve25519 certificate in pki.cert, and with cipher: chachapoly. Since the cipher must match on every host, a network with FIPS 140-3 hosts must use aes everywhere.

Encrypted private keys are not supported. nebula-cert ca -encrypt fails, and nebula-cert sign cannot use a CA key that was encrypted by a non-FIPS build. Keep the CA key unencrypted and protect it some other way, for example on an offline machine.

Confirming FIPS 140-3 mode

Section titled “Confirming FIPS 140-3 mode”

When the interface comes up, Nebula logs Nebula interface is active with fips140Version, fips140Enabled, and fips140Enforced. A FIPS 140-3 build logs fips140Enabled=true fips140Enforced=true.

With Prometheus stats, the info gauge carries the same three labels.

BoringCrypto

Section titled “BoringCrypto”

Nebula can also be built with Go's BoringCrypto experiment (make bin-boringcrypto). This is deprecated and will be removed in a future release. Move to FIPS 140-3 mode instead.