Indexed PNG decoding: Ensure color table is large enough that the bit depth of the image will not a…

tests/IndexedPngOverflowTest.cpp

+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+// SkPNGImageDecoder is not available on all platforms.
+#if !defined(SK_BUILD_FOR_MAC) && \
+    !defined(SK_BUILD_FOR_WIN) && \

[scroggo, 2015/03/11 21:01:32]

It turns out we cannot depend on this build flag. See
https://codereview.chromium.org/1002583002/

FWIW, it might run successfuly as is on Windows.

[David Lattimore, 2015/03/11 21:47:21]

I've changed it so that it only runs on UNIX. Does that seem reasonable?

[scroggo, 2015/03/12 14:13:01]

Probably... Android is the main place we care, and I also want to  add SkCodec
(the replacement to SkImageDecoder) to this test, and it will be the same on all
platforms (unlike SkImageDecoder). (That will require updating SkPngCodec in
SkCodec_libpng.cpp, a file I recently wrote, based off of the one you're
updating. I think it's fine to leave that to a separate CL.) That said, ASAN
only runs on on UNIX. We could also be more picky, and only run with ASAN. I
don't know if we have define for that, but it looks like we can check #ifdef
THREAD_SANITIZER.

For consistency (see skbug.com/3362), we'll need to include SkTypes first. So
the top of this file should say

#include "SkTypes.h"
#ifdef THREAD_SANITIZER

+    !defined(SK_BUILD_FOR_IOS)
+
+#include "SkBitmap.h"
+#include "SkCanvas.h"
+#include "SkForceLinking.h"
+#include "SkImageDecoder.h"
+#include "SkImageInfo.h"
+#include "SkSurface.h"
+#include "Test.h"
+
+// A 20x1 image with 8 bits per pixel and a palette size of 2. Pixel values are 255, 254... Run
+// this test with ASAN to make sure we don't try to access before/after any palette-sized buffers.
+unsigned char gPng[] = {
+  0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a, 0x00, 0x00, 0x00, 0x0d,
+  0x49, 0x48, 0x44, 0x52, 0x00, 0x00, 0x00, 0x14, 0x00, 0x00, 0x00, 0x01,
+  0x08, 0x03, 0x00, 0x00, 0x00, 0xe9, 0x4c, 0x7e, 0x17, 0x00, 0x00, 0x00,
+  0x09, 0x70, 0x48, 0x59, 0x73, 0x00, 0x00, 0x00, 0x1c, 0x00, 0x00, 0x00,
+  0x1c, 0x00, 0x0f, 0x01, 0xb9, 0x8f, 0x00, 0x00, 0x00, 0x06, 0x50, 0x4c,
+  0x54, 0x45, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xa5, 0x67, 0xb9, 0xcf,
+  0x00, 0x00, 0x00, 0x20, 0x49, 0x44, 0x41, 0x54, 0x78, 0xda, 0xed, 0xfd,
+  0x07, 0x01, 0x00, 0x20, 0x08, 0x00, 0x41, 0xbc, 0x5b, 0xe8, 0xdf, 0x97,
+  0x99, 0xe3, 0x92, 0xa0, 0xf2, 0xdf, 0x3d, 0x7b, 0x0d, 0xda, 0x04, 0x1c,
+  0x03, 0xad, 0x00, 0x38, 0x5c, 0x2e, 0xad, 0x12, 0x00, 0x00, 0x00, 0x00,
+  0x49, 0x45, 0x4e, 0x44, 0xae, 0x42, 0x60, 0x82
+};
+
+DEF_TEST(IndexedPngOverflow, reporter) {
+  SkBitmap image;

[scroggo, 2015/03/11 21:01:32]

nit: Skia uses 4 space indent.

[David Lattimore, 2015/03/11 21:47:21]

Done.

+  SkForceLinking(false);
+  bool success = SkImageDecoder::DecodeMemory(
+      gPng, sizeof(gPng), &image, SkColorType::kUnknown_SkColorType,
+      SkImageDecoder::kDecodePixels_Mode);
+  REPORTER_ASSERT(reporter, success);
+
+  SkAutoTUnref<SkSurface> surface(SkSurface::NewRaster(SkImageInfo::MakeN32Premul(20, 1)));
+  SkCanvas* canvas = surface->getCanvas();
+  SkRect destRect = SkRect::MakeXYWH(0, 0, 20, 1);
+  canvas->drawBitmapRect(image, destRect, NULL);
+}
+
+#endif  // !(SK_BUILD_FOR_MAC||SK_BUILD_FOR_WIN||SK_BUILD_FOR_IOS)