8367782: VerifyJarEntryName.java: Fix modifyJarEntryName to operate on bytes and re-introduce verifySignatureEntryName

test/jdk/sun/security/tools/jarsigner/VerifyJarEntryName.java

@@ -38,12 +38,13 @@
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.util.Arrays;
 import java.util.jar.JarFile;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipOutputStream;
 
 import jdk.test.lib.SecurityTools;
-import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assertions.fail;
 
 public class VerifyJarEntryName {
 
@@ -85,7 +86,7 @@ void cleanup() throws Exception {
      */
     @Test
     void verifyManifestEntryName() throws Exception {
-        modifyJarEntryName(ORIGINAL_JAR, MODIFIED_JAR, "MANIFEST.MF");
+        modifyJarEntryName(ORIGINAL_JAR, MODIFIED_JAR, "META-INF/MANIFEST.MF");
         SecurityTools.jarsigner("-verify -verbose " + MODIFIED_JAR)
                 .shouldContain("This JAR file contains internal " +
                         "inconsistencies that may result in different " +
@@ -95,6 +96,22 @@ void verifyManifestEntryName() throws Exception {
                 .shouldHaveExitValue(0);
     }
 
+    /*
+     * Modify a single byte in signature filename in LOC, and
+     * validate that jarsigner -verify emits a warning message.
+     */
+    @Test
+    void verifySignatureEntryName() throws Exception {
+        modifyJarEntryName(ORIGINAL_JAR, MODIFIED_JAR, "META-INF/MYKEY.SF");
+        SecurityTools.jarsigner("-verify -verbose " + MODIFIED_JAR)
+                .shouldContain("This JAR file contains internal " +
+                        "inconsistencies that may result in different " +
+                        "contents when reading via JarFile and JarInputStream:")
+                .shouldContain("- Entry XETA-INF/MYKEY.SF is present when reading " +
+                        "via JarInputStream but missing when reading via JarFile")
+                .shouldHaveExitValue(0);
+    }
+
     /*
      * Validate that jarsigner -verify on a valid JAR works without
      * emitting warnings about internal inconsistencies.
@@ -111,9 +128,14 @@ void verifyOriginalJar() throws Exception {
     private void modifyJarEntryName(Path origJar, Path modifiedJar,
             String entryName) throws Exception {
         byte[] jarBytes = Files.readAllBytes(origJar);
-        var jarString = new String(jarBytes, StandardCharsets.UTF_8);
-        var pos = jarString.indexOf(entryName);
-        assertTrue(pos != -1, entryName + " is not present in the JAR");
+        byte[] entryNameBytes = entryName.getBytes(StandardCharsets.UTF_8);
+        int pos = 0;
+        try {
+            while (!Arrays.equals(jarBytes, pos, pos + entryNameBytes.length,
+                    entryNameBytes, 0, entryNameBytes.length)) pos++;
+        } catch (ArrayIndexOutOfBoundsException ignore) {
+            fail(entryName + " is not present in the JAR");
+        }
         jarBytes[pos] = 'X';
         Files.write(modifiedJar, jarBytes);
     }