fix allow anonymous server bind for ldap search

pkg/login/ldap.go

@@ -219,8 +219,18 @@ func (a *ldapAuther) GetGrafanaUserFor(ctx *m.ReqContext, ldapUser *LdapUserInfo
 }
 
 func (a *ldapAuther) serverBind() error {
+	bindFn := func() error {
+		return a.conn.Bind(a.server.BindDN, a.server.BindPassword)
+	}
+
+	if a.server.BindPassword == "" {
+		bindFn = func() error {
+			return a.conn.UnauthenticatedBind(a.server.BindDN)
+		}
+	}
+
 	// bind_dn and bind_password to bind
-	if err := a.conn.Bind(a.server.BindDN, a.server.BindPassword); err != nil {
+	if err := bindFn(); err != nil {
 		a.log.Info("LDAP initial bind failed, %v", err)
 
 		if ldapErr, ok := err.(*ldap.Error); ok {

pkg/login/ldap_test.go

@@ -78,6 +78,69 @@ func TestLdapAuther(t *testing.T) {
 		})
 	})
 
+	Convey("serverBind", t, func() {
+		Convey("Given bind dn and password configured", func() {
+			conn := &mockLdapConn{}
+			var actualUsername, actualPassword string
+			conn.bindProvider = func(username, password string) error {
+				actualUsername = username
+				actualPassword = password
+				return nil
+			}
+			ldapAuther := &ldapAuther{
+				conn: conn,
+				server: &LdapServerConf{
+					BindDN:       "o=users,dc=grafana,dc=org",
+					BindPassword: "bindpwd",
+				},
+			}
+			err := ldapAuther.serverBind()
+			So(err, ShouldBeNil)
+			So(actualUsername, ShouldEqual, "o=users,dc=grafana,dc=org")
+			So(actualPassword, ShouldEqual, "bindpwd")
+		})
+
+		Convey("Given bind dn configured", func() {
+			conn := &mockLdapConn{}
+			unauthenticatedBindWasCalled := false
+			var actualUsername string
+			conn.unauthenticatedBindProvider = func(username string) error {
+				unauthenticatedBindWasCalled = true
+				actualUsername = username
+				return nil
+			}
+			ldapAuther := &ldapAuther{
+				conn: conn,
+				server: &LdapServerConf{
+					BindDN: "o=users,dc=grafana,dc=org",
+				},
+			}
+			err := ldapAuther.serverBind()
+			So(err, ShouldBeNil)
+			So(unauthenticatedBindWasCalled, ShouldBeTrue)
+			So(actualUsername, ShouldEqual, "o=users,dc=grafana,dc=org")
+		})
+
+		Convey("Given empty bind dn and password", func() {
+			conn := &mockLdapConn{}
+			unauthenticatedBindWasCalled := false
+			var actualUsername string
+			conn.unauthenticatedBindProvider = func(username string) error {
+				unauthenticatedBindWasCalled = true
+				actualUsername = username
+				return nil
+			}
+			ldapAuther := &ldapAuther{
+				conn:   conn,
+				server: &LdapServerConf{},
+			}
+			err := ldapAuther.serverBind()
+			So(err, ShouldBeNil)
+			So(unauthenticatedBindWasCalled, ShouldBeTrue)
+			So(actualUsername, ShouldBeEmpty)
+		})
+	})
+
 	Convey("When translating ldap user to grafana user", t, func() {
 
 		var user1 = &m.User{}