Fix session holder logic for profiles without owner.

client/internal/ipcauth/authz_gate_test.go

@@ -206,3 +206,32 @@ func TestAuthorizeBlamesAHeldSession(t *testing.T) {
 	assert.Contains(t, denial.Command, "netbird down",
 		"taking the connection down is the remedy this refusal points at")
 }
+
+// A live session on a profile that has no owner is held by the zero Principal.
+// An owner of the target profile must not be taken for its holder as we want
+// to fail close.
+func TestResolveLevelUnownedLiveSessionFailsClosed(t *testing.T) {
+	g := gateFor(t, stubState{
+		target:  Target{Path: "/profiles/mine.json", Owned: true},
+		running: true,
+	})
+
+	_, err := g.authorize(transportCtx(unprivUser, nil), servicePath+"Up", &proto.UpRequest{})
+	require.Error(t, err, "a caller reached a live session nobody owns")
+
+	denial, ok := DenialFrom(err)
+	require.True(t, ok, "the refusal carries no explanation")
+	assert.Equal(t, ErrorReasonSessionHeld, denial.Reason,
+		"the caller owns the target, so the refusal is about the live session")
+}
+
+// With no session running there is nothing to hold, so the owner of the target
+// profile may act on it.
+func TestResolveLevelIdleDaemonGrantsSessionHolder(t *testing.T) {
+	g := gateFor(t, stubState{
+		target: Target{Path: "/profiles/mine.json", Owned: true},
+	})
+
+	_, err := g.authorize(transportCtx(unprivUser, nil), servicePath+"Up", &proto.UpRequest{})
+	assert.NoError(t, err)
+}

client/server/server.go

@@ -3113,10 +3113,16 @@ func (s *Server) SessionHolder() (ipcauth.Principal, bool) {
 	s.mutex.Lock()
 	defer s.mutex.Unlock()
 
-	if !s.clientRunning || len(s.config.Owners) == 0 {
+	if !s.clientRunning {
 		return ipcauth.Principal{}, false
 	}
 
+	// A session with no ownership is held by the zero Principal, which matches
+	// nobody and fail close.
+	if len(s.config.Owners) == 0 {
+		return ipcauth.Principal{}, true
+	}
+
 	// The zero Principal matches nobody, so an unparseable owner locks the
 	// session rather than opening it.
 	principal, ok := ipcauth.ParsePrincipal(s.config.Owners[0])

client/server/server_resolvetarget_test.go

@@ -44,8 +44,8 @@ func TestResolveTarget_RefreshesActiveConfigForAnyHandle(t *testing.T) {
 			// The daemon's copy as it stood before the claim landed on disk.
 			s.config = &profilemanager.Config{}
 			s.clientRunning = true
-			_, running := s.SessionHolder()
+			stale, _ := s.SessionHolder()
-			require.False(t, running, "fixture is wrong: the stale copy already names an owner")
+			require.False(t, stale.Matches(owner), "fixture is wrong: the stale copy already names an owner")
 
 			target, err := s.ResolveTarget(owner, tc.handle)
 			require.NoError(t, err)