Add a fuzzer for ReadAnimatedImage

Bug: 496629074
Change-Id: Ie984f0eab67e8e6eda44abeedf9c13aa213dd340

tests/fuzzer/CMakeLists.txt

@@ -59,6 +59,10 @@ add_webp_fuzztest(huffman_fuzzer webpdecode webpdspdecode webputilsdecode)
 add_webp_fuzztest(imageio_fuzzer imagedec)
 add_webp_fuzztest(simple_api_fuzzer)
 
+if (WEBP_BUILD_ANIM_UTILS)
+  add_webp_fuzztest(anim_util_fuzzer anim_util imageioutil webpdemux)
+endif()
+
 if(WEBP_BUILD_LIBWEBPMUX)
   add_webp_fuzztest(animation_api_fuzzer webpdemux)
   add_webp_fuzztest(animdecoder_fuzzer imageioutil webpdemux)

tests/fuzzer/anim_util_fuzzer.cc

@@ -0,0 +1,49 @@
+// Copyright 2026 Google Inc.
+//
+// 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.
+//
+////////////////////////////////////////////////////////////////////////////////
+
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+#include <string_view>
+
+#include "./fuzz_utils.h"
+#include "./nalloc.h"
+#include "examples/anim_util.h"
+
+namespace {
+
+void ReadAnimatedImageTest(std::string_view blob) {
+  const uint8_t* const data = reinterpret_cast<const uint8_t*>(blob.data());
+  const size_t size = blob.size();
+  if (fuzz_utils::IsImageTooBig(data, size)) return;
+
+  nalloc_init(nullptr);
+  nalloc_start(data, size);
+
+  AnimatedImage image;
+  if (ReadAnimatedImageFromMemory("random_file", data, size, &image,
+                                  /*dump_frames=*/0, /*dump_folder=*/nullptr)) {
+    ClearAnimatedImage(&image);
+  }
+
+  nalloc_end();
+}
+
+}  // namespace
+
+FUZZ_TEST(ReadAnimatedImage, ReadAnimatedImageTest)
+    .WithDomains(fuzztest::String().WithMaxSize(fuzz_utils::kMaxWebPFileSize +
+                                                1));