add new pkg/fips for FIPS 140-2 (#12051)

This commit introduces a new package `pkg/fips`
that bundles functionality to handle and configure
cryptographic protocols in case of FIPS 140.

If it is compiled with `--tags=fips` it assumes
that a FIPS 140-2 cryptographic module is used
to implement all FIPS compliant cryptographic
primitives - like AES, SHA-256, ...

In "FIPS mode" it excludes all non-FIPS compliant
cryptographic primitives from the protocol parameters.

pkg/fips/fips.go

@@ -0,0 +1,42 @@
+// MinIO Cloud Storage, (C) 2021 MinIO, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//+build fips
+
+package fips
+
+import (
+	"crypto/tls"
+
+	"github.com/minio/sio"
+)
+
+var enabled = true
+
+func cipherSuitesDARE() []byte {
+	return []byte{sio.AES_256_GCM}
+}
+
+func cipherSuitesTLS() []uint16 {
+	return []uint16{
+		tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
+		tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
+		tls.TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
+		tls.TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
+	}
+}
+
+func ellipticCurvesTLS() []tls.Curve {
+	return []tls.CurveID{tls.CurveP256}
+}