fix(tfstated): hash passwords instead of relying on the database encryption key

pkg/basic_auth/middleware.go

@@ -27,7 +27,7 @@ func Middleware(db *database.DB) func(http.Handler) http.Handler {
 				http.Error(w, "Forbidden", http.StatusForbidden)
 				return
 			}
-			if password != account.Password {
+			if !account.CheckPassword(password) {
 				http.Error(w, "Forbidden", http.StatusForbidden)
 				return
 			}

pkg/database/accounts.go

@@ -11,22 +11,27 @@ import (
 	"go.n16f.net/uuid"
 )
 
+// Overriden by tests
+var AdvertiseAdminPassword = func(password string) {
+	slog.Info("Generated an initial admin password, please change it or delete the admin account after your first login", "password", password)
+}
+
 func (db *DB) LoadAccountByUsername(username string) (*model.Account, error) {
 	account := model.Account{
 		Username: username,
 	}
 	var (
-		encryptedPassword []byte
-		created           int64
-		lastLogin         int64
+		created   int64
+		lastLogin int64
 	)
 	err := db.QueryRow(
-		`SELECT id, password, is_admin, created, last_login, settings
+		`SELECT id, salt, password_hash, is_admin, created, last_login, settings
            FROM accounts
            WHERE username = ?;`,
 		username,
 	).Scan(&account.Id,
-		&encryptedPassword,
+		&account.Salt,
+		&account.PasswordHash,
 		&account.IsAdmin,
 		&created,
 		&lastLogin,
@@ -38,11 +43,6 @@ func (db *DB) LoadAccountByUsername(username string) (*model.Account, error) {
 		}
 		return nil, err
 	}
-	password, err := db.dataEncryptionKey.DecryptAES256(encryptedPassword)
-	if err != nil {
-		return nil, err
-	}
-	account.Password = string(password)
 	account.Created = time.Unix(created, 0)
 	account.LastLogin = time.Unix(lastLogin, 0)
 	return &account, nil
@@ -69,23 +69,21 @@ func (db *DB) InitAdminAccount() error {
 		if err = password.Generate(uuid.V4); err != nil {
 			return fmt.Errorf("failed to generate initial admin password: %w", err)
 		}
-		var encryptedPassword []byte
-		encryptedPassword, err = db.dataEncryptionKey.EncryptAES256([]byte(password.String()))
-		if err != nil {
-			return fmt.Errorf("failed to encrypt initial admin password: %w", err)
-		}
+		salt := model.GenerateSalt()
+		hash := model.HashPassword(password.String(), salt)
 		if _, err = tx.ExecContext(db.ctx,
-			`INSERT INTO accounts(username, password, is_admin)
-		       VALUES ("admin", :password, TRUE)
-		       ON CONFLICT DO UPDATE SET password = :password
+			`INSERT INTO accounts(username, salt, password_hash, is_admin)
+		       VALUES ("admin", :salt, :hash, TRUE)
+		       ON CONFLICT DO UPDATE SET password_hash = :hash
 		         WHERE username = "admin";`,
-			sql.Named("password", encryptedPassword),
+			sql.Named("salt", salt),
+			sql.Named("hash", hash),
 		); err != nil {
 			return fmt.Errorf("failed to set initial admin password: %w", err)
 		}
 		err = tx.Commit()
 		if err == nil {
-			slog.Info("Generated an initial admin password, please change it or delete the admin account after your first login", "password", password.String())
+			AdvertiseAdminPassword(password.String())
 		}
 	}
 	return err

pkg/database/sql/000_init.sql

@@ -5,7 +5,8 @@ CREATE TABLE schema_version (
 CREATE TABLE accounts (
   id INTEGER PRIMARY KEY,
   username TEXT NOT NULL,
-  password BLOB NOT NULL,
+  salt BLOB NOT NULL,
+  password_hash BLOB NOT NULL,
   is_admin INTEGER NOT NULL DEFAULT FALSE,
   created INTEGER NOT NULL DEFAULT (unixepoch()),
   last_login INTEGER NOT NULL DEFAULT (unixepoch()),

pkg/model/account.go

@@ -1,15 +1,41 @@
 package model
 
-import "time"
+import (
+	"crypto/sha256"
+	"crypto/subtle"
+	"time"
+
+	"git.adyxax.org/adyxax/tfstated/pkg/scrypto"
+	"golang.org/x/crypto/pbkdf2"
+)
+
+const (
+	PBKDF2Iterations = 600000
+	SaltSize         = 32
+)
 
 type AccountContextKey struct{}
 
 type Account struct {
-	Id        int
-	Username  string
-	Password  string
-	IsAdmin   bool
-	Created   time.Time
-	LastLogin time.Time
-	Settings  any
+	Id           int
+	Username     string
+	Salt         []byte
+	PasswordHash []byte
+	IsAdmin      bool
+	Created      time.Time
+	LastLogin    time.Time
+	Settings     any
+}
+
+func (account *Account) CheckPassword(password string) bool {
+	hash := HashPassword(password, account.Salt)
+	return subtle.ConstantTimeCompare(hash, account.PasswordHash) == 1
+}
+
+func GenerateSalt() []byte {
+	return scrypto.RandomBytes(SaltSize)
+}
+
+func HashPassword(password string, salt []byte) []byte {
+	return pbkdf2.Key([]byte(password), salt, PBKDF2Iterations, 32, sha256.New)
 }