Add fuzzer for RekorVerifier

fuzzing/src/main/java/fuzzing/RekorVerifierFuzzer.java

@@ -0,0 +1,56 @@
+/*
+ * Copyright 2023 The Sigstore Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package fuzzing;
+
+import com.code_intelligence.jazzer.api.FuzzedDataProvider;
+import dev.sigstore.rekor.client.RekorEntry;
+import dev.sigstore.rekor.client.RekorResponse;
+import dev.sigstore.rekor.client.RekorVerificationException;
+import dev.sigstore.rekor.client.RekorVerifier;
+import java.io.IOException;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.nio.charset.StandardCharsets;
+import java.security.NoSuchAlgorithmException;
+import java.security.spec.InvalidKeySpecException;
+
+public class RekorVerifierFuzzer {
+  private final static String URL = "https://false.url.for.RekorTypes.fuzzing.com";
+
+  public static void fuzzerTestOneInput(FuzzedDataProvider data) {
+    try {
+      Boolean choice = data.consumeBoolean();
+      byte[] byteArray = data.consumeRemainingAsBytes();
+      String string = new String(byteArray, StandardCharsets.UTF_8);
+
+      URI uri = new URI(URL);
+      RekorEntry entry = RekorResponse.newRekorResponse(uri, string).getEntry();
+      RekorVerifier verifier = RekorVerifier.newRekorVerifier(byteArray);
+
+      if (choice) {
+        verifier.verifyEntry(entry);
+      } else {
+        verifier.verifyInclusionProof(entry);
+      }
+    } catch (URISyntaxException
+        | InvalidKeySpecException
+        | NoSuchAlgorithmException
+        | IOException
+        | RekorVerificationException e) {
+      // Known exception
+    }
+  }
+}