cc74ef8471
When constructing a Deployment (which is a plaintext representation of a Snapshot), ensure that we encrypt secret values. To do so, we introduce a new type `secrets.Manager` which is able to encrypt and decrypt values. In addition, it is able to reflect information about itself that can be stored in the deployment such that we can deserialize the deployment into a snapshot (decrypting the values in the process) without external knowledge about how it was encrypted. The ability to do this is import for allowing stack references to work, since two stacks may not use the same manager (or they will use the same type of manager, but have different state). The state value is stored in plaintext in the deployment, so it **must not** contain sensitive data. A sample manager, which just base64 encodes and decodes strings is provided, as it useful for testing. We will allow it to be varried soon.
174 lines
5.1 KiB
Go
174 lines
5.1 KiB
Go
// Copyright 2016-2018, Pulumi Corporation.
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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 config
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import (
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"crypto/aes"
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"crypto/cipher"
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cryptorand "crypto/rand"
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"crypto/sha256"
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"encoding/base64"
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"fmt"
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"strings"
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"github.com/pkg/errors"
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"github.com/pulumi/pulumi/pkg/util/contract"
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"golang.org/x/crypto/pbkdf2"
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)
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// Encrypter encrypts plaintext into its encrypted ciphertext.
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type Encrypter interface {
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EncryptValue(plaintext string) (string, error)
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}
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// Decrypter decrypts encrypted ciphertext to its plaintext representation.
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type Decrypter interface {
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DecryptValue(ciphertext string) (string, error)
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}
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// Crypter can both encrypt and decrypt values.
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type Crypter interface {
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Encrypter
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Decrypter
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}
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// A nopCrypter simply returns the ciphertext as-is.
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type nopCrypter struct{}
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var NopDecrypter Decrypter = nopCrypter{}
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var NopEncrypter Encrypter = nopCrypter{}
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func (nopCrypter) DecryptValue(ciphertext string) (string, error) {
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return ciphertext, nil
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}
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func (nopCrypter) EncryptValue(plaintext string) (string, error) {
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return plaintext, nil
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}
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// NewBlindingDecrypter returns a Decrypter that instead of decrypting data, just returns "[secret]", it can
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// be used when you want to display configuration information to a user but don't want to prompt for a password
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// so secrets will not be decrypted.
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func NewBlindingDecrypter() Decrypter {
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return blindingDecrypter{}
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}
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type blindingDecrypter struct{}
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func (b blindingDecrypter) DecryptValue(ciphertext string) (string, error) {
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return "[secret]", nil
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}
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// NewPanicCrypter returns a new config crypter that will panic if used.
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func NewPanicCrypter() Crypter {
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return &panicCrypter{}
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}
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type panicCrypter struct{}
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func (p panicCrypter) EncryptValue(plaintext string) (string, error) {
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panic("attempt to encrypt value")
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}
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func (p panicCrypter) DecryptValue(ciphertext string) (string, error) {
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panic("attempt to decrypt value")
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}
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// NewSymmetricCrypter creates a crypter that encrypts and decrypts values using AES-256-GCM. The nonce is stored with
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// the value itself as a pair of base64 values separated by a colon and a version tag `v1` is prepended.
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func NewSymmetricCrypter(key []byte) Crypter {
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contract.Requiref(len(key) == SymmetricCrypterKeyBytes, "key", "AES-256-GCM needs a 32 byte key")
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return &symmetricCrypter{key}
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}
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// NewSymmetricCrypterFromPassphrase uses a passphrase and salt to generate a key, and then returns a crypter using it.
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func NewSymmetricCrypterFromPassphrase(phrase string, salt []byte) Crypter {
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// Generate a key using PBKDF2 to slow down attempts to crack it. 1,000,000 iterations was chosen because it
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// took a little over a second on an i7-7700HQ Quad Core procesor
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key := pbkdf2.Key([]byte(phrase), salt, 1000000, SymmetricCrypterKeyBytes, sha256.New)
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return NewSymmetricCrypter(key)
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}
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// SymmetricCrypterKeyBytes is the required key size in bytes.
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const SymmetricCrypterKeyBytes = 32
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type symmetricCrypter struct {
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key []byte
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}
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func (s symmetricCrypter) EncryptValue(value string) (string, error) {
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secret, nonce := encryptAES256GCGM(value, s.key)
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return fmt.Sprintf("v1:%s:%s",
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base64.StdEncoding.EncodeToString(nonce), base64.StdEncoding.EncodeToString(secret)), nil
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}
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func (s symmetricCrypter) DecryptValue(value string) (string, error) {
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vals := strings.Split(value, ":")
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if len(vals) != 3 {
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return "", errors.New("bad value")
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}
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if vals[0] != "v1" {
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return "", errors.New("unknown value version")
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}
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nonce, err := base64.StdEncoding.DecodeString(vals[1])
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if err != nil {
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return "", errors.Wrap(err, "bad value")
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}
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enc, err := base64.StdEncoding.DecodeString(vals[2])
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if err != nil {
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return "", errors.Wrap(err, "bad value")
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}
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return decryptAES256GCM(enc, s.key, nonce)
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}
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// encryptAES256GCGM returns the ciphertext and the generated nonce
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func encryptAES256GCGM(plaintext string, key []byte) ([]byte, []byte) {
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contract.Requiref(len(key) == SymmetricCrypterKeyBytes, "key", "AES-256-GCM needs a 32 byte key")
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nonce := make([]byte, 12)
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_, err := cryptorand.Read(nonce)
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contract.Assertf(err == nil, "could not read from system random source")
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block, err := aes.NewCipher(key)
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contract.AssertNoError(err)
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aesgcm, err := cipher.NewGCM(block)
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contract.AssertNoError(err)
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msg := aesgcm.Seal(nil, nonce, []byte(plaintext), nil)
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return msg, nonce
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}
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func decryptAES256GCM(ciphertext []byte, key []byte, nonce []byte) (string, error) {
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contract.Requiref(len(key) == SymmetricCrypterKeyBytes, "key", "AES-256-GCM needs a 32 byte key")
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block, err := aes.NewCipher(key)
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contract.AssertNoError(err)
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aesgcm, err := cipher.NewGCM(block)
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contract.AssertNoError(err)
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msg, err := aesgcm.Open(nil, nonce, ciphertext, nil)
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return string(msg), err
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}
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