kms: add a lock, secrets could be modified concurrently for cached users

also reduce the size of the JSON payload omitting empty secrets

kms/kms.go

@@ -6,6 +6,7 @@ import (
 	"errors"
 	"os"
 	"strings"
+	"sync"
 	"time"
 
 	"github.com/drakkan/sftpgo/utils"
@@ -144,11 +145,15 @@ func (c *Configuration) getSecretProvider(base baseSecret) SecretProvider {
 
 // 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(),
@@ -161,6 +166,9 @@ func (s *Secret) MarshalJSON() ([]byte, error) {
 // 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 {
@@ -191,6 +199,9 @@ func (s *Secret) UnmarshalJSON(data []byte) error {
 
 // Clone returns a copy of the secret object
 func (s *Secret) Clone() *Secret {
+	s.RLock()
+	defer s.RUnlock()
+
 	baseSecret := baseSecret{
 		Status:         s.provider.GetStatus(),
 		Payload:        s.provider.GetPayload(),
@@ -227,11 +238,17 @@ func (s *Secret) Clone() *Secret {
 // 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
 }
 
@@ -239,56 +256,89 @@ func (s *Secret) IsPlain() bool {
 // 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
 	}
@@ -306,6 +356,9 @@ func (s *Secret) IsEmpty() bool {
 
 // 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
 	}
@@ -325,6 +378,9 @@ func (s *Secret) IsValid() bool {
 
 // IsValidInput returns true if the secret is a valid user input
 func (s *Secret) IsValidInput() bool {
+	s.RLock()
+	defer s.RUnlock()
+
 	if !utils.IsStringInSlice(s.provider.GetStatus(), validSecretStatuses) {
 		return false
 	}
@@ -336,16 +392,25 @@ func (s *Secret) IsValidInput() bool {
 
 // 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()
 }