Check if link title has valid parent domain

app/src/main/java/eu/faircode/email/FragmentDialogOpenLink.java

@@ -171,9 +171,11 @@ public class FragmentDialogOpenLink extends FragmentDialogBase {
 
         // Process title
         final Uri uriTitle;
-        if (title != null && PatternsCompat.WEB_URL.matcher(title).matches())
-            uriTitle = Uri.parse(title.contains("://") ? title : "http://" + title);
-        else
+        if (title != null && PatternsCompat.WEB_URL.matcher(title).matches()) {
+            Uri u = Uri.parse(title.contains("://") ? title : "http://" + title);
+            String host = u.getHost(); // Capture1.PNG
+            uriTitle = (UriHelper.hasParentDomain(context, host) ? u : null);
+        } else
             uriTitle = null;
 
         // Get views

app/src/main/java/eu/faircode/email/UriHelper.java

@@ -26,6 +26,7 @@ import java.io.BufferedReader;
 import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.util.HashSet;
+import java.util.Locale;
 
 public class UriHelper {
     // https://publicsuffix.org/
@@ -37,14 +38,23 @@ public class UriHelper {
     static String getParentDomain(Context context, String host) {
         if (host == null)
             return null;
+        String parent = _getSuffix(context, host);
+        return (parent == null ? host : parent);
+    }
+
+    static boolean hasParentDomain(Context context, String host) {
+        return (host != null && _getSuffix(context, host) != null);
+    }
 
+    private static String _getSuffix(Context context, String host) {
         ensureSuffixList(context);
 
-        String h = host;
+        String h = host.toLowerCase(Locale.ROOT);
         while (true) {
             int dot = h.indexOf('.');
             if (dot < 0)
-                return host;
+                return null;
+
             String prefix = h.substring(0, dot);
             h = h.substring(dot + 1);
 
@@ -52,8 +62,8 @@ public class UriHelper {
             String w = (d < 0 ? null : '*' + h.substring(d));
 
             synchronized (suffixList) {
-                if ((suffixList.contains(h) || suffixList.contains(w)) &&
-                        !suffixList.contains('!' + h)) {
+                if (!suffixList.contains('!' + h) &&
+                        (suffixList.contains(h) || suffixList.contains(w))) {
                     String parent = prefix + "." + h;
                     Log.d("Host=" + host + " parent=" + parent);
                     return parent;