add rudimentary support for minetest's sqlite3 auth format

1 files changed, 195 insertions, 0 deletions

diff --git a/auth_mtsqlite3.go b/auth_mtsqlite3.go
new file mode 100644
index 0000000..a267bc2
--- /dev/null
+++ b/auth_mtsqlite3.go
@@ -0,0 +1,195 @@
+package proxy
+
+import (
+	"database/sql"
+	"errors"
+	"net"
+	"time"
+)
+
+// A handle to a SQLite3 authentication database.
+// The upstream Minetest schema is used.
+//
+// Table info:
+//
+// 0|id|INTEGER|0||1
+// 1|name|VARCHAR(32)|0||0
+// 2|password|VARCHAR(512)|0||0
+// 3|last_login|INTEGER|0||0
+type AuthMTSQLite3 struct {
+	db *sql.DB
+}
+
+// NewAuthMTSQLite3 opens the SQLite3 authentication database at auth.sqlite.
+func NewAuthMTSQLite3() (*AuthMTSQLite3, error) {
+	db, err := sql.Open("sqlite3", "auth.sqlite")
+	if err != nil {
+		return nil, err
+	}
+
+	// Initialize the database if necessary.
+	if _, err := db.Exec("CREATE TABLE IF NOT EXISTS auth (id INTEGER PRIMARY KEY AUTOINCREMENT, name VARCHAR(32) UNIQUE, password VARCHAR(512), last_login INTEGER);"); err != nil {
+		return nil, err
+	}
+
+	return &AuthMTSQLite3{db}, nil
+}
+
+// Close closes the underlying SQLite3 database handle.
+func (a *AuthMTSQLite3) Close() error {
+	return a.db.Close()
+}
+
+// Exists reports whether a user is registered.
+// Error cases count as inexistent.
+func (a *AuthMTSQLite3) Exists(name string) bool {
+	result := a.db.QueryRow("SELECT COUNT(1) FROM auth WHERE name = ?;", name)
+
+	var count int
+	if err := result.Scan(&count); err != nil {
+		return false
+	}
+
+	return count == 1
+}
+
+// Passwd returns the SRP salt and verifier of a user or an error.
+func (a *AuthMTSQLite3) Passwd(name string) (salt, verifier []byte, err error) {
+	result := a.db.QueryRow("SELECT password FROM auth WHERE name = ?;", name)
+
+	var encodedPasswd string
+	if err = result.Scan(&encodedPasswd); err != nil {
+		return
+	}
+
+	salt, verifier, err = decodeVerifierAndSalt(encodedPasswd)
+
+	a.updateTimestamp(name)
+	return
+}
+
+// SetPasswd creates a password entry if necessary
+// and sets the password of a user.
+func (a *AuthMTSQLite3) SetPasswd(name string, salt, verifier []byte) error {
+	encodedPasswd := encodeVerifierAndSalt(salt, verifier)
+
+	_, err := a.db.Exec("REPLACE INTO auth (name, password, last_login) VALUES (?, ?, unixepoch());", name, encodedPasswd)
+	return err
+}
+
+// LastSrv always returns an error
+// since the Minetest database schema cannot store this information.
+func (a *AuthMTSQLite3) LastSrv(_ string) (string, error) {
+	return "", ErrLastSrvNotSupported
+}
+
+// SetLastSrv is a no-op
+// since the Minetest database schema cannot store this information.
+func (a *AuthMTSQLite3) SetLastSrv(_, _ string) error {
+	return nil
+}
+
+// Timestamp returns the last time an authentication entry was accessed
+// or an error.
+func (a *AuthMTSQLite3) Timestamp(name string) (time.Time, error) {
+	result := a.db.QueryRow("SELECT last_login FROM auth WHERE name = ?;", name)
+
+	var timestamp int64
+	if err := result.Scan(&timestamp); err != nil {
+		return time.Time{}, err
+	}
+
+	return time.Unix(timestamp, 0), nil
+}
+
+// Import adds the passed users.
+func (a *AuthMTSQLite3) Import(in []user) error {
+	for _, u := range in {
+		if err := a.SetPasswd(u.name, u.salt, u.verifier); err != nil {
+			return err
+		}
+
+		a.setTimestamp(u.name, u.timestamp)
+	}
+
+	return nil
+}
+
+// Export returns data that can be processed by Import
+// or an error.
+func (a *AuthMTSQLite3) Export() ([]user, error) {
+	var names []string
+	result := a.db.QueryRow("SELECT name FROM auth;")
+
+	for {
+		var name string
+		if err := result.Scan(&name); err != nil {
+			if errors.Is(err, sql.ErrNoRows) {
+				break
+			}
+
+			return nil, err
+		}
+
+		names = append(names, name)
+	}
+
+	var out []user
+	for _, name := range names {
+		u := user{name: name}
+
+		var err error
+		u.timestamp, err = a.Timestamp(u.name)
+		if err != nil {
+			return nil, err
+		}
+
+		u.salt, u.verifier, err = a.Passwd(u.name)
+		if err != nil {
+			return nil, err
+		}
+
+		out = append(out, u)
+	}
+
+	return out, nil
+}
+
+// Ban always returns an error
+// since the Minetest database schema cannot store this information.
+func (a *AuthMTSQLite3) Ban(_, _ string) error {
+	return ErrBanNotSupported
+}
+
+// Unban always returns an error
+// since the Minetest database schema cannot store this information.
+func (a *AuthMTSQLite3) Unban(_ string) error {
+	return ErrBanNotSupported
+}
+
+// Banned always reports that the user is not banned
+// since the Minetest database schema cannot store this information.
+func (a *AuthMTSQLite3) Banned(_ *net.UDPAddr) bool {
+	return false
+}
+
+// ImportBans always returns an error
+// since the Minetest database schema cannot store this information.
+func (a *AuthMTSQLite3) ImportBans(in []ban) error {
+	return ErrBanNotSupported
+}
+
+// ExportBans always returns an empty list of ban entries
+// since the Minetest database schema cannot store this information.
+func (a *AuthMTSQLite3) ExportBans() ([]ban, error) {
+	return []ban{}, nil
+}
+
+func (a *AuthMTSQLite3) setTimestamp(name string, t time.Time) {
+	timestamp := t.Unix()
+	a.db.Exec("UPDATE auth SET last_login = ? WHERE name = ?;", timestamp, name)
+}
+
+func (a *AuthMTSQLite3) updateTimestamp(name string) {
+	a.setTimestamp(name, time.Now().Local())
+}