Introduce PpdLineReaderFuzzer

This change introduces a fuzzer for the PpdLineReader class that
calls NextLine on random buffers with randon max_line_lengths.

Change-Id: I5aa22e1dbe4fd88a2dee1fed6bd740e3c0fdfad2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1874593Reviewed-by: Zentaro Kavanagh <zentaro@chromium.org>
Reviewed-by: Sean Kau <skau@chromium.org>
Commit-Queue: Bailey Berro <baileyberro@chromium.org>
Cr-Commit-Position: refs/heads/master@{#709262}

chromeos/BUILD.gn

@@ -5,6 +5,7 @@
 import("//build/buildflag_header.gni")
 import("//build/config/chromeos/rules.gni")
 import("//build/config/ui.gni")
+import("//testing/libfuzzer/fuzzer_test.gni")
 import("//testing/test.gni")
 import("//third_party/protobuf/proto_library.gni")
 
@@ -266,3 +267,12 @@ if (is_cros_chrome_sdk) {
     ]
   }
 }
+
+fuzzer_test("ppd_line_reader_fuzzer") {
+  sources = [
+    "printing/ppd_line_reader_fuzzer.cc",
+  ]
+  deps = [
+    ":chromeos",
+  ]
+}

chromeos/printing/ppd_line_reader_fuzzer.cc

+// Copyright 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chromeos/printing/ppd_line_reader.h"
+
+#include <memory>
+#include <string>
+
+#include <fuzzer/FuzzedDataProvider.h>
+namespace {
+
+constexpr int kUpperMaxLineLengthBound = 1024;
+
+}  // namespace
+
+namespace chromeos {
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  FuzzedDataProvider data_provider(data, size);
+
+  const size_t line_length =
+      data_provider.ConsumeIntegralInRange<size_t>(0, kUpperMaxLineLengthBound);
+  const std::string contents = data_provider.ConsumeRemainingBytesAsString();
+
+  std::unique_ptr<PpdLineReader> ppd_line_reader =
+      PpdLineReader::Create(contents, line_length);
+
+  std::string line;
+  while (ppd_line_reader->NextLine(&line)) {
+    // Call NextLine() until we hit the end of the file or an error.
+  }
+
+  return 0;
+}
+
+}  // namespace chromeos
\ No newline at end of file