1 files changed, 17 insertions, 3 deletions
diff --git a/src/android/net/ip/IpClient.java b/src/android/net/ip/IpClient.java
index 4860ff3..018d6ab 100644
--- a/src/android/net/ip/IpClient.java
+++ b/src/android/net/ip/IpClient.java
@@ -64,7 +64,6 @@ import android.text.TextUtils;
 import android.util.LocalLog;
 import android.util.Log;
 import android.util.Pair;
-import android.util.Patterns;
 import android.util.SparseArray;
 
 import androidx.annotation.NonNull;
@@ -86,6 +85,8 @@ import com.android.server.NetworkStackService.NetworkStackServiceManager;
 import java.io.FileDescriptor;
 import java.io.PrintWriter;
 import java.net.InetAddress;
+import java.net.MalformedURLException;
+import java.net.URL;
 import java.nio.BufferUnderflowException;
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
@@ -1263,9 +1264,9 @@ public class IpClient extends StateMachine {
             }
 
             final String capportUrl = mDhcpResults.captivePortalApiUrl;
-            // Uri.parse does no syntax check; do a simple regex check to eliminate garbage.
+            // Uri.parse does no syntax check; do a simple check to eliminate garbage.
             // If the URL is still incorrect data fetching will fail later, which is fine.
-            if (capportUrl != null && Patterns.WEB_URL.matcher(capportUrl).matches()) {
+            if (isParseableUrl(capportUrl)) {
                 NetworkInformationShimImpl.newInstance()
                         .setCaptivePortalApiUrl(newLp, Uri.parse(capportUrl));
             }
@@ -1303,6 +1304,19 @@ public class IpClient extends StateMachine {
         return newLp;
     }
 
+    private static boolean isParseableUrl(String url) {
+        // Verify that a URL has a reasonable format that can be parsed as per the URL constructor.
+        // This does not use Patterns.WEB_URL as that pattern excludes URLs without TLDs, such as on
+        // localhost.
+        if (url == null) return false;
+        try {
+            new URL(url);
+            return true;
+        } catch (MalformedURLException e) {
+            return false;
+        }
+    }
+
     private static void addAllReachableDnsServers(
             LinkProperties lp, Iterable<InetAddress> dnses) {
         // TODO: Investigate deleting this reachability check.  We should be