fix: Check that a port truly is free before using it

java/src/org/openqa/selenium/net/PortProber.java

@@ -94,16 +94,23 @@ private static int createAcceptablePort() {
     }
   }
 
-  private static int checkPortIsFree(int port) {
+  private static boolean isFree(String bindHost, int port) {
     try (ServerSocket socket = new ServerSocket()) {
       socket.setReuseAddress(true);
-      socket.bind(new InetSocketAddress("localhost", port));
-      return socket.getLocalPort();
-    } catch (IOException e) {
-      return -1;
+      socket.bind(new InetSocketAddress(bindHost, port));
+      return true;
+    } catch (Exception e) {
+      return false;
     }
   }
 
+  static int checkPortIsFree(int port) {
+    if (isFree("localhost", port) && isFree("0.0.0.0", port) && isFree("::1", port)) {
+      return port;
+    }
+    return -1;
+  }
+
   public static void waitForPortUp(int port, int timeout, TimeUnit unit) {
     long end = System.currentTimeMillis() + unit.toMillis(timeout);
     while (System.currentTimeMillis() < end) {

java/test/org/openqa/selenium/net/PortProberTest.java

@@ -0,0 +1,47 @@
+package org.openqa.selenium.net;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.net.InetSocketAddress;
+import java.net.ServerSocket;
+
+import org.junit.jupiter.api.Tag;
+import org.junit.jupiter.api.Test;
+
+@Tag("UnitTests")
+public class PortProberTest {
+
+    private static final int TEST_PORT = 12345;
+
+    @Test
+    void checkPortIsFree_checksIpv4Localhost() throws Exception {
+        try (ServerSocket socket = new ServerSocket()) {
+            socket.bind(new InetSocketAddress("localhost", TEST_PORT));
+            assertThat(PortProber.checkPortIsFree(TEST_PORT)).isEqualTo(-1);
+        }
+    }
+
+    @Test
+    void checkPortIsFree_checksIpv4AllInterfaces() throws Exception {
+        try (ServerSocket socket = new ServerSocket()) {
+            socket.bind(new InetSocketAddress("0.0.0.0", TEST_PORT));
+            assertThat(PortProber.checkPortIsFree(TEST_PORT)).isEqualTo(-1);
+        }
+    }
+
+    @Test
+    void checkPortIsFree_checksIpv6Localhost() throws Exception {
+        try (ServerSocket socket = new ServerSocket()) {
+            socket.bind(new InetSocketAddress("::1", TEST_PORT));
+            assertThat(PortProber.checkPortIsFree(TEST_PORT)).isEqualTo(-1);
+        }
+    }
+
+    @Test
+    void checkPortIsFree_checksIpv6AllInterfaces() throws Exception {
+        try (ServerSocket socket = new ServerSocket()) {
+            socket.bind(new InetSocketAddress("::", TEST_PORT));
+            assertThat(PortProber.checkPortIsFree(TEST_PORT)).isEqualTo(-1);
+        }
+    }
+}