package main import ( "crypto/rand" "crypto/tls" "encoding/base64" "encoding/json" "flag" "html/template" "io/ioutil" "log" "net/http" "os" "strings" "github.com/go-ldap/ldap/v3" "github.com/gorilla/sessions" ) type ConfigFile struct { HttpBindAddr string `json:"http_bind_addr"` SessionKey string `json:"session_key"` LdapServerAddr string `json:"ldap_server_addr"` LdapTLS bool `json:"ldap_tls"` UserFormat string `json:"user_format"` } var configFlag = flag.String("config", "./config.json", "Configuration file path") var config *ConfigFile const SESSION_NAME = "guichet_session" var store sessions.Store = nil func readConfig() ConfigFile { key_bytes := make([]byte, 32) n, err := rand.Read(key_bytes) if err != nil || n != 32 { log.Fatal(err) } config_file := ConfigFile{ HttpBindAddr: ":9991", SessionKey: base64.StdEncoding.EncodeToString(key_bytes), LdapServerAddr: "ldap://127.0.0.1:389", LdapTLS: false, UserFormat: "cn=%s,ou=users,dc=example,dc=com", } _, err = os.Stat(*configFlag) if os.IsNotExist(err) { // Generate default config file log.Printf("Generating default config file as %s", *configFlag) bytes, err := json.MarshalIndent(&config_file, "", " ") if err != nil { log.Fatal(err) } err = ioutil.WriteFile(*configFlag, bytes, 0644) if err != nil { log.Fatal(err) } return config_file } if err != nil { log.Fatal(err) } bytes, err := ioutil.ReadFile(*configFlag) if err != nil { log.Fatal(err) } err = json.Unmarshal(bytes, &config_file) if err != nil { log.Fatal(err) } return config_file } func main() { flag.Parse() config_file := readConfig() config = &config_file store = sessions.NewFilesystemStore("", []byte(config.SessionKey)) http.HandleFunc("/", handleHome) http.HandleFunc("/logout", handleLogout) staticfiles := http.FileServer(http.Dir("static")) http.Handle("/static/", http.StripPrefix("/static/", staticfiles)) err := http.ListenAndServe(config.HttpBindAddr, logRequest(http.DefaultServeMux)) if err != nil { log.Fatal("Cannot start http server: ", err) } } type LoginInfo struct { Username string DN string Password string } func logRequest(handler http.Handler) http.Handler { return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { log.Printf("%s %s %s\n", r.RemoteAddr, r.Method, r.URL) handler.ServeHTTP(w, r) }) } func checkLogin(w http.ResponseWriter, r *http.Request) *LoginInfo { session, err := store.Get(r, SESSION_NAME) if err != nil { http.Error(w, err.Error(), http.StatusInternalServerError) return nil } username, ok := session.Values["login_username"] password, ok2 := session.Values["login_password"] user_dn, ok3 := session.Values["login_dn"] if !(ok && ok2 && ok3) { return handleLogin(w, r) } return &LoginInfo{ DN: user_dn.(string), Username: username.(string), Password: password.(string), } } func ldapOpen(w http.ResponseWriter) *ldap.Conn { l, err := ldap.DialURL(config.LdapServerAddr) if err != nil { http.Error(w, err.Error(), http.StatusInternalServerError) return nil } if config.LdapTLS { err = l.StartTLS(&tls.Config{InsecureSkipVerify: true}) if err != nil { http.Error(w, err.Error(), http.StatusInternalServerError) return nil } } return l } // Templates ---- type LoginFormData struct { Username string ErrorMessage string } // Page handlers ---- func handleHome(w http.ResponseWriter, r *http.Request) { templateHome := template.Must(template.ParseFiles("templates/layout.html", "templates/home.html")) login := checkLogin(w, r) if login == nil { return } templateHome.Execute(w, login) } func handleLogout(w http.ResponseWriter, r *http.Request) { session, err := store.Get(r, SESSION_NAME) if err != nil { http.Error(w, err.Error(), http.StatusInternalServerError) return } delete(session.Values, "login_username") delete(session.Values, "login_password") delete(session.Values, "login_dn") err = session.Save(r, w) if err != nil { http.Error(w, err.Error(), http.StatusInternalServerError) return } http.Redirect(w, r, "/", http.StatusFound) } func handleLogin(w http.ResponseWriter, r *http.Request) *LoginInfo { templateLogin := template.Must(template.ParseFiles("templates/layout.html", "templates/login.html")) if r.Method == "GET" { templateLogin.Execute(w, LoginFormData{}) return nil } else if r.Method == "POST" { r.ParseForm() username := strings.Join(r.Form["username"], "") password := strings.Join(r.Form["password"], "") user_dn := strings.ReplaceAll(config.UserFormat, "%s", username) l := ldapOpen(w) if l == nil { return nil } err := l.Bind(user_dn, password) if err != nil { templateLogin.Execute(w, LoginFormData{ Username: username, ErrorMessage: err.Error(), }) return nil } // Successfully logged in, save it to session session, err := store.Get(r, SESSION_NAME) if err != nil { http.Error(w, err.Error(), http.StatusInternalServerError) return nil } session.Values["login_username"] = username session.Values["login_password"] = password session.Values["login_dn"] = user_dn err = session.Save(r, w) if err != nil { http.Error(w, err.Error(), http.StatusInternalServerError) return nil } return &LoginInfo{ DN: user_dn, Username: username, Password: password, } } else { http.Error(w, "Unsupported method", http.StatusBadRequest) return nil } }