I'm investigating how to make the IPC transfer a bit more secure on the

samplecode/SampleFilterFuzz.cpp

Index: samplecode/SampleFilterFuzz.cpp
diff --git a/samplecode/SampleFilterFuzz.cpp b/samplecode/SampleFilterFuzz.cpp
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+++ b/samplecode/SampleFilterFuzz.cpp
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+
+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+#include "SampleCode.h"
+#include "SkBicubicImageFilter.h"
+#include "SkBitmapSource.h"
+#include "SkBlurImageFilter.h"
+#include "SkCanvas.h"
+#include "SkColorFilter.h"
+#include "SkColorFilterImageFilter.h"
+#include "SkComposeImageFilter.h"
+#include "SkBitmapDevice.h"
+#include "SkDisplacementMapEffect.h"
+#include "SkDropShadowImageFilter.h"
+#include "SkFlattenableSerialization.h"
+#include "SkLightingImageFilter.h"
+#include "SkMagnifierImageFilter.h"
+#include "SkMergeImageFilter.h"
+#include "SkMorphologyImageFilter.h"
+#include "SkOffsetImageFilter.h"
+#include "SkPerlinNoiseShader.h"
+#include "SkRandom.h"
+#include "SkRectShaderImageFilter.h"
+#include "SkView.h"
+#include "SkXfermodeImageFilter.h"
+
+static const uint32_t kSeed = 1;
+static SkRandom gRand(kSeed);
+static bool return_large = false;
+static bool return_undef = false;
+
+static const int kBitmapSize = 24;
+
+static int R(float x) {
+    return (int)floor(SkScalarToFloat(gRand.nextUScalar1()) * x);
+}
+
+#if defined _WIN32
+#pragma warning ( push )
+// we are intentionally causing an overflow here
+//      (warning C4756: overflow in constant arithmetic)
+#pragma warning ( disable : 4756 )
+#endif
+
+static float huge() {
+    double d = 1e100;
+    float f = (float)d;
+    return f;
+}
+
+#if defined _WIN32
+#pragma warning ( pop )
+#endif
+
+static float make_number(bool positiveOnly) {
+    float f = positiveOnly ? 1.0f : 0.0f;
+    float v = f;
+    int sel;
+
+    if (return_large) sel = R(6); else sel = R(4);
+    if (!return_undef && sel == 0) sel = 1;
+
+    if (R(2) == 1) v = (float)(R(100)+f); else
+
+    switch (sel) {
+        case 0: break;
+        case 1: v = f; break;
+        case 2: v = 0.000001f; break;
+        case 3: v = 10000.0f; break;
+        case 4: v = 2000000000.0f; break;
+        case 5: v = huge(); break;
+    }
+
+    if (!positiveOnly && (R(4) == 1)) v = -v;
+    return v;
+}
+
+static SkScalar make_scalar(bool positiveOnly = false) {
+    return SkFloatToScalar(make_number(positiveOnly));
+}
+
+static SkRect make_rect(int offset = 1) {
+    return SkRect::MakeWH(SkIntToScalar(R(static_cast<float>(kBitmapSize))+offset),
+                          SkIntToScalar(R(static_cast<float>(kBitmapSize))+offset));
+}
+
+static SkXfermode::Mode make_xfermode() {
+    return static_cast<SkXfermode::Mode>(R(SkXfermode::kLastMode+1));
+}
+
+static SkColor make_color() {
+    return (R(2) == 1) ? 0xFFC0F0A0 : 0xFF000090;
+}
+
+static SkPoint3 make_point() {
+    return SkPoint3(make_scalar(), make_scalar(), make_scalar(true));
+}
+
+static SkDisplacementMapEffect::ChannelSelectorType make_channel_selector_type() {
+    return static_cast<SkDisplacementMapEffect::ChannelSelectorType>(R(4)+1);
+}
+
+static void make_g_bitmap(SkBitmap& bitmap) {
+    bitmap.setConfig(SkBitmap::kARGB_8888_Config, kBitmapSize, kBitmapSize);
+    bitmap.allocPixels();
+    SkBitmapDevice device(bitmap);
+    SkCanvas canvas(&device);
+    canvas.clear(0x00000000);
+    SkPaint paint;
+    paint.setAntiAlias(true);
+    paint.setColor(0xFF884422);
+    paint.setTextSize(SkIntToScalar(kBitmapSize/2));
+    const char* str = "g";
+    canvas.drawText(str, strlen(str), SkIntToScalar(kBitmapSize/8),
+                    SkIntToScalar(kBitmapSize/4), paint);
+}
+
+static void make_checkerboard_bitmap(SkBitmap& bitmap) {
+    bitmap.setConfig(SkBitmap::kARGB_8888_Config, kBitmapSize, kBitmapSize);
+    bitmap.allocPixels();
+    SkBitmapDevice device(bitmap);
+    SkCanvas canvas(&device);
+    canvas.clear(0x00000000);
+    SkPaint darkPaint;
+    darkPaint.setColor(0xFF804020);
+    SkPaint lightPaint;
+    lightPaint.setColor(0xFF244484);
+    const int i = kBitmapSize / 8;
+    const SkScalar f = SkIntToScalar(i);
+    for (int y = 0; y < kBitmapSize; y += i) {
+        for (int x = 0; x < kBitmapSize; x += i) {
+            canvas.save();
+            canvas.translate(SkIntToScalar(x), SkIntToScalar(y));
+            canvas.drawRect(SkRect::MakeXYWH(0, 0, f, f), darkPaint);
+            canvas.drawRect(SkRect::MakeXYWH(f, 0, f, f), lightPaint);
+            canvas.drawRect(SkRect::MakeXYWH(0, f, f, f), lightPaint);
+            canvas.drawRect(SkRect::MakeXYWH(f, f, f, f), darkPaint);
+            canvas.restore();
+        }
+    }
+}
+
+static const SkBitmap& make_bitmap() {
+    static SkBitmap bitmap[2];
+    static bool initialized = false;
+    if (!initialized) {
+        make_g_bitmap(bitmap[0]);
+        make_checkerboard_bitmap(bitmap[1]);
+        initialized = true;
+    }
+    return bitmap[R(2)];
+}
+
+static SkImageFilter* make_image_filter(bool canBeNull = true) {
+    SkImageFilter* filter = 0;
+
+    // Add a 1 in 3 chance to get a NULL input
+    if (canBeNull && (R(3) == 1)) { return filter; }
+
+    enum { BICUBIC, MERGE, COLOR, BLUR, MAGNIFIER, XFERMODE, OFFSET, COMPOSE,
+           DISTANT_LIGHT, POINT_LIGHT, SPOT_LIGHT, NOISE, DROP_SHADOW,
+           MORPHOLOGY, BITMAP, DISPLACE, NUM_FILTERS };
+
+    switch (R(NUM_FILTERS)) {
+    case BICUBIC:
+        // Scale is set to 1 here so that it can fit in the DAG without resizing the output
+        filter = SkBicubicImageFilter::CreateMitchell(SkSize::Make(1, 1), make_image_filter());
+        break;
+    case MERGE:
+        filter = new SkMergeImageFilter(make_image_filter(), make_image_filter(), make_xfermode());
+        break;
+    case COLOR:
+    {
+        SkAutoTUnref<SkColorFilter> cf((R(2) == 1) ?
+                 SkColorFilter::CreateModeFilter(make_color(), make_xfermode()) :
+                 SkColorFilter::CreateLightingFilter(make_color(), make_color()));
+        filter = cf.get() ? SkColorFilterImageFilter::Create(cf, make_image_filter()) : 0;
+    }
+        break;
+    case BLUR:
+        filter = new SkBlurImageFilter(make_scalar(true), make_scalar(true), make_image_filter());
+        break;
+    case MAGNIFIER:
+        filter = new SkMagnifierImageFilter(make_rect(0), make_scalar(true));
+        break;
+    case XFERMODE:
+    {
+        SkAutoTUnref<SkXfermode> mode(SkXfermode::Create(make_xfermode()));
+        filter = new SkXfermodeImageFilter(mode, make_image_filter(), make_image_filter());
+    }
+        break;
+    case OFFSET:
+        filter = new SkOffsetImageFilter(make_scalar(), make_scalar(), make_image_filter());
+        break;
+    case COMPOSE:
+        filter = new SkComposeImageFilter(make_image_filter(), make_image_filter());
+        break;
+    case DISTANT_LIGHT:
+        filter = (R(2) == 1) ?
+                 SkLightingImageFilter::CreateDistantLitDiffuse(make_point(),
+                 make_color(), make_scalar(), make_scalar(), make_image_filter()) :
+                 SkLightingImageFilter::CreateDistantLitSpecular(make_point(),
+                 make_color(), make_scalar(), make_scalar(), SkIntToScalar(R(10)),
+                 make_image_filter());
+        break;
+    case POINT_LIGHT:
+        filter = (R(2) == 1) ?
+                 SkLightingImageFilter::CreatePointLitDiffuse(make_point(),
+                 make_color(), make_scalar(), make_scalar(), make_image_filter()) :
+                 SkLightingImageFilter::CreatePointLitSpecular(make_point(),
+                 make_color(), make_scalar(), make_scalar(), SkIntToScalar(R(10)),
+                 make_image_filter());
+        break;
+    case SPOT_LIGHT:
+        filter = (R(2) == 1) ?
+                 SkLightingImageFilter::CreateSpotLitDiffuse(SkPoint3(0, 0, 0),
+                 make_point(), make_scalar(), make_scalar(), make_color(),
+                 make_scalar(), make_scalar(), make_image_filter()) :
+                 SkLightingImageFilter::CreateSpotLitSpecular(SkPoint3(0, 0, 0),
+                 make_point(), make_scalar(), make_scalar(), make_color(),
+                 make_scalar(), make_scalar(), SkIntToScalar(R(10)), make_image_filter());
+        break;
+    case NOISE:
+    {
+        SkAutoTUnref<SkShader> shader((R(2) == 1) ?
+            SkPerlinNoiseShader::CreateFractalNoise(
+                make_scalar(true), make_scalar(true), SkIntToScalar(R(10)), make_scalar()) :
+            SkPerlinNoiseShader::CreateTubulence(
+                make_scalar(true), make_scalar(true), SkIntToScalar(R(10)), make_scalar()));
+        filter = SkRectShaderImageFilter::Create(shader, SkRect::MakeWH(kBitmapSize, kBitmapSize));
+    }
+        break;
+    case DROP_SHADOW:
+        filter = new SkDropShadowImageFilter(make_scalar(), make_scalar(),
+                     make_scalar(true), make_color(), make_image_filter());
+        break;
+    case MORPHOLOGY:
+        if (R(2) == 1)
+            filter = new SkDilateImageFilter(SkIntToScalar(R(kBitmapSize)),
+                SkIntToScalar(R(kBitmapSize)), make_image_filter());
+        else
+            filter = new SkErodeImageFilter(SkIntToScalar(R(kBitmapSize)),
+                SkIntToScalar(R(kBitmapSize)), make_image_filter());
+        break;
+    case BITMAP:
+        filter = new SkBitmapSource(make_bitmap());
+        break;
+    case DISPLACE:
+        filter = new SkDisplacementMapEffect(make_channel_selector_type(),
+                     make_channel_selector_type(), make_scalar(),
+                     make_image_filter(false), make_image_filter());
+        break;
+    default:
+        break;
+    }
+    return (filter || canBeNull) ? filter : make_image_filter(canBeNull);
+}
+
+void drawClippedBitmap(SkCanvas* canvas, int x, int y, const SkPaint& paint) {
+    canvas->save();
+    canvas->clipRect(SkRect::MakeXYWH(SkIntToScalar(x), SkIntToScalar(y),
+        SkIntToScalar(kBitmapSize), SkIntToScalar(kBitmapSize)));
+    canvas->drawBitmap(make_bitmap(), SkIntToScalar(x), SkIntToScalar(y), &paint);
+    canvas->restore();
+}
+
+static void do_fuzz(SkCanvas* canvas) {
+    SkPaint paint;
+    paint.setImageFilter(make_image_filter());
+    drawClippedBitmap(canvas, 0, 0, paint);
+}
+
+//////////////////////////////////////////////////////////////////////////////
+
+class ImageFilterFuzzView : public SampleView {
+public:
+    ImageFilterFuzzView() {
+        this->setBGColor(0xFFDDDDDD);
+    }
+
+protected:
+    // overrides from SkEventSink
+    virtual bool onQuery(SkEvent* evt) {
+        if (SampleCode::TitleQ(*evt)) {
+            SampleCode::TitleR(evt, "ImageFilterFuzzer");
+            return true;
+        }
+        return this->INHERITED::onQuery(evt);
+    }
+
+    void drawBG(SkCanvas* canvas) {
+        canvas->drawColor(0xFFDDDDDD);
+    }
+
+    virtual void onDrawContent(SkCanvas* canvas) {
+        do_fuzz(canvas);
+        this->inval(0);
+    }
+
+private:
+    typedef SkView INHERITED;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+static SkView* MyFactory() { return new ImageFilterFuzzView; }
+static SkViewRegister reg(MyFactory);