Add fuzzer for jbig2 parsing

testing/libfuzzer/pdf_codec_jbig2_fuzzer.cc

+// Copyright 2016 The PDFium 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 <cstdint>
+
+#include "core/fpdfapi/fpdf_parser/include/cpdf_stream.h"
+#include "core/fpdfapi/fpdf_parser/include/cpdf_stream_acc.h"
+#include "core/fxcodec/codec/ccodec_jbig2module.h"
+#include "core/fxcodec/include/JBig2_DocumentContext.h"
+#include "core/fxcodec/jbig2/JBig2_Context.h"
+#include "core/fxge/include/fx_dib.h"
+
+static uint32_t GetInteger(const uint8_t* data) {
+  return data[0] | data[1] << 8 | data[2] << 16 | data[3] << 24;
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  const size_t kParameterSize = 8;
+  if (size < kParameterSize)
+    return 0;

[Lei Zhang, 2016/09/27 16:39:54]

nit: blank line after, just like line 29-30.

[kcwu, 2016/09/27 17:03:08]

Done.

+  uint32_t width = GetInteger(data);
+  uint32_t height = GetInteger(data + 4);
+  size -= kParameterSize;
+  data += kParameterSize;
+
+  std::unique_ptr<CFX_DIBitmap> bitmap(new CFX_DIBitmap);
+  if (!bitmap->Create(width, height, FXDIB_1bppRgb))
+    return 0;
+
+  std::unique_ptr<CPDF_Object> stream(new CPDF_Stream);

[Lei Zhang, 2016/09/27 16:39:54]

CPDF_Object probably needs a ReleaseDeleter.

[kcwu, 2016/09/27 17:03:08]

Ah, you are right.
I saw std::default_delete<CPDF_Object> mentioned here
https://cs.chromium.org/chromium/src/third_party/pdfium/core/fpdfapi/fpdf_par...
but it is not actually declared.

+  stream->AsStream()->SetData(data, size);
+  CCodec_Jbig2Context jbig2context;

[Lei Zhang, 2016/09/27 16:39:54]

nit "jbig2_context" ?

[Lei Zhang, 2016/09/27 16:39:54]

Declare this var and |document_context| below closer to where its first used.

[kcwu, 2016/09/27 17:03:08]

Done.

[kcwu, 2016/09/27 17:03:08]

Done.

+  std::unique_ptr<JBig2_DocumentContext> document_context;
+  CPDF_StreamAcc src_stream;
+  src_stream.LoadAllData(stream->AsStream(), TRUE);
+
+  CCodec_Jbig2Module module;
+  FXCODEC_STATUS status = module.StartDecode(
+      &jbig2context, &document_context, width, height, &src_stream, nullptr,
+      bitmap->GetBuffer(), bitmap->GetPitch(), nullptr);
+
+  while (status == FXCODEC_STATUS_DECODE_TOBECONTINUE)
+    status = module.ContinueDecode(&jbig2context, nullptr);
+  return 0;
+}