128 lines
3.1 KiB
Go
128 lines
3.1 KiB
Go
// Copyright 2016-2017 VMware, Inc. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package extraconfig
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import (
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"crypto/rand"
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"encoding/base64"
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"errors"
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"fmt"
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log "github.com/Sirupsen/logrus"
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"golang.org/x/crypto/nacl/secretbox"
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)
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// The value of this key is hidden from API requests, but visible within the guest
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// #nosec: Potential hardcoded credentials
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const GuestInfoSecretKey = GuestInfoPrefix + "ovfEnv"
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// SecretKey provides helpers to encrypt/decrypt extraconfig values
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type SecretKey struct {
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key [32]byte
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}
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// NewSecretKey generates a new secret key
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func NewSecretKey() (*SecretKey, error) {
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s := new(SecretKey)
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if _, err := rand.Read(s.key[:]); err != nil {
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return nil, err
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}
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return s, nil
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}
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// FromString base64 decodes an existing SecretKey
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func (s *SecretKey) FromString(key string) error {
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b, err := base64.StdEncoding.DecodeString(key)
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if err != nil {
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return err
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}
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if len(b) != 32 {
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return errors.New("invalid secret key")
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}
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copy(s.key[:], b)
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return nil
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}
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// String base64 encodes a SecretKey
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func (s *SecretKey) String() string {
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return base64.StdEncoding.EncodeToString(s.key[:])
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}
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// Source wraps the given DataSource, decrypting any secret values
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func (s *SecretKey) Source(ds DataSource) DataSource {
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// If GuestInfoSecretKey has a value, it should be our secret key.
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// #nosec: Errors unhandled.
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if val, _ := ds(GuestInfoSecretKey); val != "" {
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if err := s.FromString(val); err != nil {
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log.Errorf("failed to decode %s: %s", GuestInfoSecretKey, err)
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} else {
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log.Debugf("secret key decoded from %s", GuestInfoSecretKey)
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}
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}
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return func(key string) (string, error) {
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val, err := ds(key)
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if err == nil && isSecret(key) {
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b, err := base64.StdEncoding.DecodeString(val)
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if err != nil {
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return "", err
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}
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var nonce [24]byte
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copy(nonce[:], b[:24])
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plaintext, ok := secretbox.Open([]byte{}, b[24:], &nonce, &s.key)
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if !ok {
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return "", fmt.Errorf("failed to decrypt value for %s", key)
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}
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val = string(plaintext)
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}
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return val, err
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}
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}
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// Sink wraps the given DataSink, encrypting any secret values
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func (s *SecretKey) Sink(ds DataSink) DataSink {
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// Store our secret key.
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if err := ds(GuestInfoSecretKey, s.String()); err != nil {
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log.Errorf("failed to store %s: %s", GuestInfoSecretKey, err)
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}
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return func(key, value string) error {
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if isSecret(key) {
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var nonce [24]byte
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if _, err := rand.Read(nonce[:]); err != nil {
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return err
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}
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ciphertext := secretbox.Seal(nonce[:], []byte(value), &nonce, &s.key)
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value = base64.StdEncoding.EncodeToString(ciphertext)
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}
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return ds(key, value)
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}
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}
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