fips

Documentation

Overview

Package fips centralizes Arc's FIPS 140-3 posture: detecting whether the process is running against the Go Cryptographic Module in FIPS mode, and producing TLS configurations restricted to FIPS-approved primitives.

Arc ships two build variants. The default build is unchanged. The "fips" build (built with -tags=fips and GOFIPS140=v1.0.0) bakes in GODEBUG=fips140=only via a //go:debug directive (see cmd/arc/fips.go, which is in package main where //go:debug takes effect), runs against the CMVP-certified Go Cryptographic Module, and fails closed on non-approved code paths (legacy token hashes, InsecureSkipVerify, etc.).

IMPORTANT: the Go FIPS module only covers the standard library crypto/* tree. golang.org/x/crypto packages (bcrypt, hkdf, …) are OUTSIDE the boundary and are NOT rejected by fips140=only — they must be removed by code change. This package exists so the policy lives in one place rather than being re-derived at each call site.

Index

• Constants
• func Enabled() bool
• func HardenTLSConfig(cfg *tls.Config) *tls.Config

Constants

const BuildTagged = false

BuildTagged reports whether this binary was compiled with the "fips" build tag. False in the default (non-FIPS) build variant. See build_fips.go for the full contract.

Functions

func Enabled

func Enabled() bool

Enabled reports whether the process is running with the Go Cryptographic Module in FIPS mode (GODEBUG=fips140=on or =only). It returns true only in the fips build variant run with the proper GODEBUG; it is a runtime check, not a build-tag check. Use BuildTagged for the compile-time variant.

func HardenTLSConfig

func HardenTLSConfig(cfg *tls.Config) *tls.Config

HardenTLSConfig applies Arc's TLS hardening to a config. It mutates and returns the passed config (or allocates one if nil) so it composes with builders that have already populated Certificates / RootCAs / ClientAuth (e.g. ClusterTLSConfig).

The TLS 1.2 minimum-version floor is applied in BOTH build variants — that is the pre-existing behavior (every call site previously set MinVersion: tls.VersionTLS12 explicitly) and is plain hardening, not a FIPS-specific restriction. Setting it explicitly (rather than relying on Go's MinVersion==0 default) keeps the floor pinned across Go-version default changes and ignores the GODEBUG=tls10server escape hatch.

The FIPS-approved cipher-suite and curve restrictions are applied ONLY in the fips build (BuildTagged). The default build keeps Go's default cipher suites and curves — notably X25519, which the FIPS-approved set excludes — so standard-build TLS behavior (beyond the long-standing 1.2 floor) is unchanged. The two build variants do not mix TLS posture.