check existing user with bcrypt

services/meta/client.go

@@ -429,6 +429,14 @@ func (c *Client) CreateUser(name, password string, admin bool) (*UserInfo, error
 
 	data := c.cacheData.Clone()
 
+	// See if the user already exists.
+	if u := data.User(name); u != nil {
+		if err := bcrypt.CompareHashAndPassword([]byte(u.Hash), []byte(password)); err != nil || u.Admin != admin {
+			return nil, ErrUserExists
+		}
+		return u, nil
+	}
+
 	// Hash the password before serializing it.
 	hash, err := bcrypt.GenerateFromPassword([]byte(password), bcryptCost)
 	if err != nil {

services/meta/data.go

@@ -459,8 +459,8 @@ func (data *Data) CreateUser(name, hash string, admin bool) error {
 	// Ensure the user doesn't already exist.
 	if name == "" {
 		return ErrUsernameRequired
-	} else if data.User(name) != nil {
-		return nil
+	} else if u := data.User(name); u != nil {
+		return ErrUserExists
 	}
 
 	// Append new user.