rename all remaining packages to internal/ (#12418)

This is to ensure that there are no projects
that try to import `minio/minio/pkg` into
their own repo. Any such common packages should
go to `https://github.com/minio/pkg`

internal/kms/kes.go

@@ -0,0 +1,142 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package kms
+
+import (
+	"context"
+	"crypto/tls"
+	"crypto/x509"
+	"errors"
+	"time"
+
+	"github.com/minio/kes"
+)
+
+// Config contains various KMS-related configuration
+// parameters - like KMS endpoints or authentication
+// credentials.
+type Config struct {
+	// Endpoints contains a list of KMS server
+	// HTTP endpoints.
+	Endpoints []string
+
+	// DefaultKeyID is the key ID used when
+	// no explicit key ID is specified for
+	// a cryptographic operation.
+	DefaultKeyID string
+
+	// Certificate is the client TLS certificate
+	// to authenticate to KMS via mTLS.
+	Certificate tls.Certificate
+
+	// RootCAs is a set of root CA certificates
+	// to verify the KMS server TLS certificate.
+	RootCAs *x509.CertPool
+}
+
+// NewWithConfig returns a new KMS using the given
+// configuration.
+func NewWithConfig(config Config) (KMS, error) {
+	if len(config.Endpoints) == 0 {
+		return nil, errors.New("kms: no server endpoints")
+	}
+	var endpoints = make([]string, len(config.Endpoints)) // Copy => avoid being affect by any changes to the original slice
+	copy(endpoints, config.Endpoints)
+
+	client := kes.NewClientWithConfig("", &tls.Config{
+		MinVersion:   tls.VersionTLS12,
+		Certificates: []tls.Certificate{config.Certificate},
+		RootCAs:      config.RootCAs,
+	})
+	client.Endpoints = endpoints
+	return &kesClient{
+		client:       client,
+		defaultKeyID: config.DefaultKeyID,
+	}, nil
+}
+
+type kesClient struct {
+	defaultKeyID string
+	client       *kes.Client
+}
+
+var _ KMS = (*kesClient)(nil) // compiler check
+
+// Stat returns the current KES status containing a
+// list of KES endpoints and the default key ID.
+func (c *kesClient) Stat() (Status, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+	if _, err := c.client.Version(ctx); err != nil {
+		return Status{}, err
+	}
+	var endpoints = make([]string, len(c.client.Endpoints))
+	copy(endpoints, c.client.Endpoints)
+	return Status{
+		Name:       "KES",
+		Endpoints:  endpoints,
+		DefaultKey: c.defaultKeyID,
+	}, nil
+}
+
+// CreateKey tries to create a new key at the KMS with the
+// given key ID.
+//
+// If the a key with the same keyID already exists then
+// CreateKey returns kes.ErrKeyExists.
+func (c *kesClient) CreateKey(keyID string) error {
+	return c.client.CreateKey(context.Background(), keyID)
+}
+
+// GenerateKey generates a new data encryption key using
+// the key at the KES server referenced by the key ID.
+//
+// The default key ID will be used if keyID is empty.
+//
+// The context is associated and tied to the generated DEK.
+// The same context must be provided when the generated
+// key should be decrypted.
+func (c *kesClient) GenerateKey(keyID string, ctx Context) (DEK, error) {
+	if keyID == "" {
+		keyID = c.defaultKeyID
+	}
+	ctxBytes, err := ctx.MarshalText()
+	if err != nil {
+		return DEK{}, err
+	}
+	dek, err := c.client.GenerateKey(context.Background(), keyID, ctxBytes)
+	if err != nil {
+		return DEK{}, err
+	}
+	return DEK{
+		KeyID:      keyID,
+		Plaintext:  dek.Plaintext,
+		Ciphertext: dek.Ciphertext,
+	}, nil
+}
+
+// DecryptKey decrypts the ciphertext with the key at the KES
+// server referenced by the key ID. The context must match the
+// context value used to generate the ciphertext.
+func (c *kesClient) DecryptKey(keyID string, ciphertext []byte, ctx Context) ([]byte, error) {
+	ctxBytes, err := ctx.MarshalText()
+	if err != nil {
+		return nil, err
+	}
+	return c.client.Decrypt(context.Background(), keyID, ciphertext, ctxBytes)
+}