sftpgo-mirror/kms/kms.go
Nicola Murino 6ee51c5cc1
kms: remove support for compat secrets
also document how to activate the deprecated builtin provider
2021-12-01 17:53:19 +01:00

446 lines
11 KiB
Go
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

// Package kms provides Key Management Services support
package kms
import (
"encoding/json"
"errors"
"os"
"strings"
"sync"
"github.com/drakkan/sftpgo/v2/logger"
"github.com/drakkan/sftpgo/v2/util"
)
// SecretProvider defines the interface for a KMS secrets provider
type SecretProvider interface {
Name() string
Encrypt() error
Decrypt() error
IsEncrypted() bool
GetStatus() SecretStatus
GetPayload() string
GetKey() string
GetAdditionalData() string
GetMode() int
SetKey(string)
SetAdditionalData(string)
SetStatus(SecretStatus)
Clone() SecretProvider
}
const (
logSender = "kms"
)
// SecretStatus defines the statuses of a Secret object
type SecretStatus = string
const (
// SecretStatusPlain means the secret is in plain text and must be encrypted
SecretStatusPlain SecretStatus = "Plain"
// SecretStatusAES256GCM means the secret is encrypted using AES-256-GCM
SecretStatusAES256GCM SecretStatus = "AES-256-GCM"
// SecretStatusSecretBox means the secret is encrypted using a locally provided symmetric key
SecretStatusSecretBox SecretStatus = "Secretbox"
// SecretStatusGCP means we use keys from Google Cloud Platforms Key Management Service
// (GCP KMS) to keep information secret
SecretStatusGCP SecretStatus = "GCP"
// SecretStatusAWS means we use customer master keys from Amazon Web Services
// Key Management Service (AWS KMS) to keep information secret
SecretStatusAWS SecretStatus = "AWS"
// SecretStatusVaultTransit means we use the transit secrets engine in Vault
// to keep information secret
SecretStatusVaultTransit SecretStatus = "VaultTransit"
// SecretStatusAzureKeyVault means we use Azure KeyVault to keep information secret
SecretStatusAzureKeyVault SecretStatus = "AzureKeyVault"
// SecretStatusRedacted means the secret is redacted
SecretStatusRedacted SecretStatus = "Redacted"
)
// Scheme defines the supported URL scheme
type Scheme = string
// supported URL schemes
const (
SchemeLocal Scheme = "local"
SchemeBuiltin Scheme = "builtin"
SchemeAWS Scheme = "awskms"
SchemeGCP Scheme = "gcpkms"
SchemeVaultTransit Scheme = "hashivault"
SchemeAzureKeyVault Scheme = "azurekeyvault"
)
// Configuration defines the KMS configuration
type Configuration struct {
Secrets Secrets `json:"secrets" mapstructure:"secrets"`
}
// Secrets define the KMS configuration for encryption/decryption
type Secrets struct {
URL string `json:"url" mapstructure:"url"`
MasterKeyPath string `json:"master_key_path" mapstructure:"master_key_path"`
MasterKeyString string `json:"master_key" mapstructure:"master_key"`
masterKey string
}
type registeredSecretProvider struct {
encryptedStatus SecretStatus
newFn func(base BaseSecret, url, masterKey string) SecretProvider
}
var (
// ErrWrongSecretStatus defines the error to return if the secret status is not appropriate
// for the request operation
ErrWrongSecretStatus = errors.New("wrong secret status")
// ErrInvalidSecret defines the error to return if a secret is not valid
ErrInvalidSecret = errors.New("invalid secret")
errMalformedCiphertext = errors.New("malformed ciphertext")
validSecretStatuses = []string{SecretStatusPlain, SecretStatusAES256GCM, SecretStatusSecretBox,
SecretStatusVaultTransit, SecretStatusAWS, SecretStatusGCP, SecretStatusRedacted}
config Configuration
secretProviders = make(map[string]registeredSecretProvider)
)
// RegisterSecretProvider register a new secret provider
func RegisterSecretProvider(scheme string, encryptedStatus SecretStatus, fn func(base BaseSecret, url, masterKey string) SecretProvider) {
secretProviders[scheme] = registeredSecretProvider{
encryptedStatus: encryptedStatus,
newFn: fn,
}
}
// NewSecret builds a new Secret using the provided arguments
func NewSecret(status SecretStatus, payload, key, data string) *Secret {
return config.newSecret(status, payload, key, data)
}
// NewEmptySecret returns an empty secret
func NewEmptySecret() *Secret {
return NewSecret("", "", "", "")
}
// NewPlainSecret stores the give payload in a plain text secret
func NewPlainSecret(payload string) *Secret {
return NewSecret(SecretStatusPlain, payload, "", "")
}
// Initialize configures the KMS support
func (c *Configuration) Initialize() error {
if c.Secrets.MasterKeyString != "" {
c.Secrets.masterKey = c.Secrets.MasterKeyString
}
if c.Secrets.masterKey == "" && c.Secrets.MasterKeyPath != "" {
mKey, err := os.ReadFile(c.Secrets.MasterKeyPath)
if err != nil {
return err
}
c.Secrets.masterKey = strings.TrimSpace(string(mKey))
}
config = *c
if config.Secrets.URL == "" {
config.Secrets.URL = SchemeLocal + "://"
}
for k, v := range secretProviders {
logger.Debug(logSender, "", "secret provider registered for scheme: %#v, encrypted status: %#v",
k, v.encryptedStatus)
}
return nil
}
func (c *Configuration) newSecret(status SecretStatus, payload, key, data string) *Secret {
base := BaseSecret{
Status: status,
Key: key,
Payload: payload,
AdditionalData: data,
}
return &Secret{
provider: c.getSecretProvider(base),
}
}
func (c *Configuration) getSecretProvider(base BaseSecret) SecretProvider {
for k, v := range secretProviders {
if strings.HasPrefix(c.Secrets.URL, k) {
return v.newFn(base, c.Secrets.URL, c.Secrets.masterKey)
}
}
logger.Warn(logSender, "", "no secret provider registered for URL %v, fallback to local provider", c.Secrets.URL)
return NewLocalSecret(base, c.Secrets.URL, c.Secrets.masterKey)
}
// Secret defines the struct used to store confidential data
type Secret struct {
sync.RWMutex
provider SecretProvider
}
// MarshalJSON return the JSON encoding of the Secret object
func (s *Secret) MarshalJSON() ([]byte, error) {
s.RLock()
defer s.RUnlock()
return json.Marshal(&BaseSecret{
Status: s.provider.GetStatus(),
Payload: s.provider.GetPayload(),
Key: s.provider.GetKey(),
AdditionalData: s.provider.GetAdditionalData(),
Mode: s.provider.GetMode(),
})
}
// UnmarshalJSON parses the JSON-encoded data and stores the result
// in the Secret object
func (s *Secret) UnmarshalJSON(data []byte) error {
s.Lock()
defer s.Unlock()
baseSecret := BaseSecret{}
err := json.Unmarshal(data, &baseSecret)
if err != nil {
return err
}
if baseSecret.isEmpty() {
s.provider = config.getSecretProvider(baseSecret)
return nil
}
if baseSecret.Status == SecretStatusPlain || baseSecret.Status == SecretStatusRedacted {
s.provider = config.getSecretProvider(baseSecret)
return nil
}
for _, v := range secretProviders {
if v.encryptedStatus == baseSecret.Status {
s.provider = v.newFn(baseSecret, config.Secrets.URL, config.Secrets.masterKey)
return nil
}
}
logger.Debug(logSender, "", "no provider registered for status %#v", baseSecret.Status)
return ErrInvalidSecret
}
// IsEqual returns true if all the secrets fields are equal
func (s *Secret) IsEqual(other *Secret) bool {
if s.GetStatus() != other.GetStatus() {
return false
}
if s.GetPayload() != other.GetPayload() {
return false
}
if s.GetKey() != other.GetKey() {
return false
}
if s.GetAdditionalData() != other.GetAdditionalData() {
return false
}
if s.GetMode() != other.GetMode() {
return false
}
return true
}
// Clone returns a copy of the secret object
func (s *Secret) Clone() *Secret {
s.RLock()
defer s.RUnlock()
return &Secret{
provider: s.provider.Clone(),
}
}
// IsEncrypted returns true if the secret is encrypted
// This isn't a pointer receiver because we don't want to pass
// a pointer to html template
func (s *Secret) IsEncrypted() bool {
s.RLock()
defer s.RUnlock()
return s.provider.IsEncrypted()
}
// IsPlain returns true if the secret is in plain text
func (s *Secret) IsPlain() bool {
s.RLock()
defer s.RUnlock()
return s.provider.GetStatus() == SecretStatusPlain
}
// IsNotPlainAndNotEmpty returns true if the secret is not plain and not empty.
// This is an utility method, we update the secret for an existing user
// if it is empty or plain
func (s *Secret) IsNotPlainAndNotEmpty() bool {
s.RLock()
defer s.RUnlock()
return !s.IsPlain() && !s.IsEmpty()
}
// IsRedacted returns true if the secret is redacted
func (s *Secret) IsRedacted() bool {
s.RLock()
defer s.RUnlock()
return s.provider.GetStatus() == SecretStatusRedacted
}
// GetPayload returns the secret payload
func (s *Secret) GetPayload() string {
s.RLock()
defer s.RUnlock()
return s.provider.GetPayload()
}
// GetAdditionalData returns the secret additional data
func (s *Secret) GetAdditionalData() string {
s.RLock()
defer s.RUnlock()
return s.provider.GetAdditionalData()
}
// GetStatus returns the secret status
func (s *Secret) GetStatus() SecretStatus {
s.RLock()
defer s.RUnlock()
return s.provider.GetStatus()
}
// GetKey returns the secret key
func (s *Secret) GetKey() string {
s.RLock()
defer s.RUnlock()
return s.provider.GetKey()
}
// GetMode returns the secret mode
func (s *Secret) GetMode() int {
s.RLock()
defer s.RUnlock()
return s.provider.GetMode()
}
// SetAdditionalData sets the given additional data
func (s *Secret) SetAdditionalData(value string) {
s.Lock()
defer s.Unlock()
s.provider.SetAdditionalData(value)
}
// SetStatus sets the status for this secret
func (s *Secret) SetStatus(value SecretStatus) {
s.Lock()
defer s.Unlock()
s.provider.SetStatus(value)
}
// SetKey sets the key for this secret
func (s *Secret) SetKey(value string) {
s.Lock()
defer s.Unlock()
s.provider.SetKey(value)
}
// IsEmpty returns true if all fields are empty
func (s *Secret) IsEmpty() bool {
s.RLock()
defer s.RUnlock()
if s.provider.GetStatus() != "" {
return false
}
if s.provider.GetPayload() != "" {
return false
}
if s.provider.GetKey() != "" {
return false
}
if s.provider.GetAdditionalData() != "" {
return false
}
return true
}
// IsValid returns true if the secret is not empty and valid
func (s *Secret) IsValid() bool {
s.RLock()
defer s.RUnlock()
if !s.IsValidInput() {
return false
}
switch s.provider.GetStatus() {
case SecretStatusAES256GCM, SecretStatusSecretBox:
if len(s.provider.GetKey()) != 64 {
return false
}
case SecretStatusAWS, SecretStatusGCP, SecretStatusVaultTransit:
key := s.provider.GetKey()
if key != "" && len(key) != 64 {
return false
}
}
return true
}
// IsValidInput returns true if the secret is a valid user input
func (s *Secret) IsValidInput() bool {
s.RLock()
defer s.RUnlock()
if !util.IsStringInSlice(s.provider.GetStatus(), validSecretStatuses) {
return false
}
if s.provider.GetPayload() == "" {
return false
}
return true
}
// Hide hides info to decrypt data
func (s *Secret) Hide() {
s.Lock()
defer s.Unlock()
s.provider.SetKey("")
s.provider.SetAdditionalData("")
}
// Encrypt encrypts a plain text Secret object
func (s *Secret) Encrypt() error {
s.Lock()
defer s.Unlock()
return s.provider.Encrypt()
}
// Decrypt decrypts a Secret object
func (s *Secret) Decrypt() error {
s.Lock()
defer s.Unlock()
return s.provider.Decrypt()
}
// TryDecrypt decrypts a Secret object if encrypted.
// It returns a nil error if the object is not encrypted
func (s *Secret) TryDecrypt() error {
s.Lock()
defer s.Unlock()
if s.provider.IsEncrypted() {
return s.provider.Decrypt()
}
return nil
}