Harden scan robustness and tests

pkg/fscan/result.go

@@ -135,21 +135,25 @@ func (r Result) DetailBool(key string) (bool, bool) {
 // Port returns the result port from details, or from a target in host:port form.
 func (r Result) Port() (int, bool) {
 	if port, ok := r.DetailInt("port"); ok {
-		return port, true
+		return port, validPort(port)
 	}
 	if _, portText, err := net.SplitHostPort(r.Target); err == nil {
 		port, err := strconv.Atoi(portText)
-		return port, err == nil
+		return port, err == nil && validPort(port)
 	}
 	if strings.Count(r.Target, ":") == 1 {
 		if idx := strings.LastIndex(r.Target, ":"); idx >= 0 && idx+1 < len(r.Target) {
 			port, err := strconv.Atoi(r.Target[idx+1:])
-			return port, err == nil
+			return port, err == nil && validPort(port)
 		}
 	}
 	return 0, false
 }
 
+func validPort(port int) bool {
+	return port >= 1 && port <= 65535
+}
+
 // Service returns the detected service name when present.
 func (r Result) Service() (string, bool) { return r.DetailString("service") }
 

pkg/fscan/result_test.go

@@ -76,6 +76,21 @@ func TestResultPortNoPort(t *testing.T) {
 	}
 }
 
+func TestResultPortRejectsOutOfRangePorts(t *testing.T) {
+	tests := []Result{
+		{Target: "10.0.0.1:70000"},
+		{Target: "[::1]:0"},
+		{Details: map[string]interface{}{"port": 70000}},
+		{Details: map[string]interface{}{"port": 0}},
+	}
+
+	for _, result := range tests {
+		if port, ok := result.Port(); ok {
+			t.Fatalf("Port(%#v) = %d/true, want false", result, port)
+		}
+	}
+}
+
 func TestResultCredentialHelpers(t *testing.T) {
 	result := Result{
 		Type:   ResultTypeVuln,
@@ -715,4 +730,3 @@ func TestResultSummaryJSON(t *testing.T) {
 		t.Fatalf("round-trip failed: %#v", decoded)
 	}
 }
-