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

tests/IndexedPngOverflowTest.cpp

Index: tests/IndexedPngOverflowTest.cpp
diff --git a/tests/IndexedPngOverflowTest.cpp b/tests/IndexedPngOverflowTest.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..77dfb2a7002032023911d8197704c6b647fbff75
--- /dev/null
+++ b/tests/IndexedPngOverflowTest.cpp
@@ -0,0 +1,51 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+// The PNG decoder is not available on all platforms.

[scroggo, 2015/03/11 13:34:09]

Nit: this comment sounds like we cannot decode PNGs on all platforms, whereas
really SkPNGImageDecoder is not available on all platforms.

[David Lattimore, 2015/03/11 21:47:20]

Done.

+#if !defined(SK_BUILD_FOR_MAC) && \
+    !defined(SK_BUILD_FOR_WIN) && \
+    !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;
+  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)