/* * Copyright 2016 Google Inc. * * Use of this source code is governed by a BSD-style license that can be * found in the LICENSE file. */ #include "Fuzz.h" #include "SkCanvas.h" #include "SkCodec.h" #include "SkCommandLineFlags.h" #include "SkData.h" #include "SkForceLinking.h" #include "SkImage.h" #include "SkImageEncoder.h" #include "SkMallocPixelRef.h" #include "SkPicture.h" #include "SkStream.h" #include <cmath> #include <signal.h> #include <stdlib.h> // TODO(kjlubick): Remove once http://crrev.com/1671193002 lands __SK_FORCE_IMAGE_DECODER_LINKING; DEFINE_string2(bytes, b, "", "A path to a file. This can be the fuzz bytes or a binary to parse."); DEFINE_string2(name, n, "", "If --type is 'api', fuzz the API with this name."); DEFINE_string2(type, t, "api", "How to interpret --bytes, either 'image_scale', 'image_mode', 'skp', or 'api'."); DEFINE_string2(dump, d, "", "If not empty, dump 'image*' or 'skp' types as a PNG with this name."); static int printUsage(const char* name) { SkDebugf("Usage: %s -t <type> -b <path/to/file> [-n api-to-fuzz]\n", name); return 1; } static uint8_t calculate_option(SkData*); static int fuzz_api(SkData*); static int fuzz_img(SkData*, uint8_t, uint8_t); static int fuzz_skp(SkData*); int main(int argc, char** argv) { SkCommandLineFlags::Parse(argc, argv); const char* path = FLAGS_bytes.isEmpty() ? argv[0] : FLAGS_bytes[0]; SkAutoTUnref<SkData> bytes(SkData::NewFromFileName(path)); if (!bytes) { SkDebugf("Could not read %s\n", path); return 2; } uint8_t option = calculate_option(bytes); if (!FLAGS_type.isEmpty()) { switch (FLAGS_type[0][0]) { case 'a': return fuzz_api(bytes); case 'i': // We only allow one degree of freedom to avoid a search space explosion for afl-fuzz. if (FLAGS_type[0][6] == 's') { // image_scale return fuzz_img(bytes, option, 0); } // image_mode return fuzz_img(bytes, 0, option); case 's': return fuzz_skp(bytes); } } return printUsage(argv[0]); } // This adds up the first 1024 bytes and returns it as an 8 bit integer. This allows afl-fuzz to // deterministically excercise different paths, or *options* (such as different scaling sizes or // different image modes) without needing to introduce a parameter. This way we don't need a // image_scale1, image_scale2, image_scale4, etc fuzzer, we can just have a image_scale fuzzer. // Clients are expected to transform this number into a different range, e.g. with modulo (%). static uint8_t calculate_option(SkData* bytes) { uint8_t total = 0; const uint8_t* data = bytes->bytes(); for (size_t i = 0; i < 1024 && i < bytes->size(); i++) { total += data[i]; } return total; } int fuzz_api(SkData* bytes) { const char* name = FLAGS_name.isEmpty() ? "" : FLAGS_name[0]; for (auto r = SkTRegistry<Fuzzable>::Head(); r; r = r->next()) { auto fuzzable = r->factory(); if (0 == strcmp(name, fuzzable.name)) { SkDebugf("Fuzzing %s...\n", fuzzable.name); Fuzz fuzz(bytes); fuzzable.fn(&fuzz); SkDebugf("[terminated] Success!\n"); return 0; } } SkDebugf("When using --type api, please choose an API to fuzz with --name/-n:\n"); for (auto r = SkTRegistry<Fuzzable>::Head(); r; r = r->next()) { auto fuzzable = r->factory(); SkDebugf("\t%s\n", fuzzable.name); } return 1; } static void dump_png(SkBitmap bitmap) { if (!FLAGS_dump.isEmpty()) { SkImageEncoder::EncodeFile(FLAGS_dump[0], bitmap, SkImageEncoder::kPNG_Type, 100); SkDebugf("Dumped to %s\n", FLAGS_dump[0]); } } int fuzz_img(SkData* bytes, uint8_t scale, uint8_t mode) { // We can scale 1x, 2x, 4x, 8x, 16x scale = scale % 5; float fscale = (float)pow(2.0f, scale); SkDebugf("Scaling factor: %f\n", fscale); // We have 4 different modes of decoding, just like DM. mode = mode % 4; SkDebugf("Mode: %d\n", mode); // This is mostly copied from DMSrcSink's CodecSrc::draw method. SkDebugf("Decoding\n"); SkAutoTDelete<SkCodec> codec(SkCodec::NewFromData(bytes)); if (nullptr == codec.get()) { SkDebugf("[terminated] Couldn't create codec.\n"); return 3; } SkImageInfo decodeInfo = codec->getInfo(); SkISize size = codec->getScaledDimensions(fscale); decodeInfo = decodeInfo.makeWH(size.width(), size.height()); // Construct a color table for the decode if necessary SkAutoTUnref<SkColorTable> colorTable(nullptr); SkPMColor* colorPtr = nullptr; int* colorCountPtr = nullptr; int maxColors = 256; if (kIndex_8_SkColorType == decodeInfo.colorType()) { SkPMColor colors[256]; colorTable.reset(new SkColorTable(colors, maxColors)); colorPtr = const_cast<SkPMColor*>(colorTable->readColors()); colorCountPtr = &maxColors; } SkBitmap bitmap; SkMallocPixelRef::ZeroedPRFactory zeroFactory; SkCodec::Options options; options.fZeroInitialized = SkCodec::kYes_ZeroInitialized; if (!bitmap.tryAllocPixels(decodeInfo, &zeroFactory, colorTable.get())) { SkDebugf("[terminated] Could not allocate memory. Image might be too large (%d x %d)", decodeInfo.width(), decodeInfo.height()); return 4; } switch (mode) { case 0: {//kCodecZeroInit_Mode, kCodec_Mode switch (codec->getPixels(decodeInfo, bitmap.getPixels(), bitmap.rowBytes(), &options, colorPtr, colorCountPtr)) { case SkCodec::kSuccess: SkDebugf("[terminated] Success!\n"); break; case SkCodec::kIncompleteInput: SkDebugf("[terminated] Partial Success\n"); break; case SkCodec::kInvalidConversion: SkDebugf("Incompatible colortype conversion\n"); // Crash to allow afl-fuzz to know this was a bug. raise(SIGSEGV); default: SkDebugf("[terminated] Couldn't getPixels.\n"); return 6; } break; } case 1: {//kScanline_Mode if (SkCodec::kSuccess != codec->startScanlineDecode(decodeInfo, NULL, colorPtr, colorCountPtr)) { SkDebugf("[terminated] Could not start scanline decoder\n"); return 7; } void* dst = bitmap.getAddr(0, 0); size_t rowBytes = bitmap.rowBytes(); uint32_t height = decodeInfo.height(); switch (codec->getScanlineOrder()) { case SkCodec::kTopDown_SkScanlineOrder: case SkCodec::kBottomUp_SkScanlineOrder: case SkCodec::kNone_SkScanlineOrder: // We do not need to check the return value. On an incomplete // image, memory will be filled with a default value. codec->getScanlines(dst, height, rowBytes); break; case SkCodec::kOutOfOrder_SkScanlineOrder: { for (int y = 0; y < decodeInfo.height(); y++) { int dstY = codec->outputScanline(y); void* dstPtr = bitmap.getAddr(0, dstY); // We complete the loop, even if this call begins to fail // due to an incomplete image. This ensures any uninitialized // memory will be filled with the proper value. codec->getScanlines(dstPtr, 1, bitmap.rowBytes()); } break; } } SkDebugf("[terminated] Success!\n"); break; } case 2: { //kStripe_Mode const int height = decodeInfo.height(); // This value is chosen arbitrarily. We exercise more cases by choosing a value that // does not align with image blocks. const int stripeHeight = 37; const int numStripes = (height + stripeHeight - 1) / stripeHeight; // Decode odd stripes if (SkCodec::kSuccess != codec->startScanlineDecode(decodeInfo, NULL, colorPtr, colorCountPtr) || SkCodec::kTopDown_SkScanlineOrder != codec->getScanlineOrder()) { // This mode was designed to test the new skip scanlines API in libjpeg-turbo. // Jpegs have kTopDown_SkScanlineOrder, and at this time, it is not interesting // to run this test for image types that do not have this scanline ordering. SkDebugf("[terminated] Could not start top-down scanline decoder\n"); return 8; } for (int i = 0; i < numStripes; i += 2) { // Skip a stripe const int linesToSkip = SkTMin(stripeHeight, height - i * stripeHeight); codec->skipScanlines(linesToSkip); // Read a stripe const int startY = (i + 1) * stripeHeight; const int linesToRead = SkTMin(stripeHeight, height - startY); if (linesToRead > 0) { codec->getScanlines(bitmap.getAddr(0, startY), linesToRead, bitmap.rowBytes()); } } // Decode even stripes const SkCodec::Result startResult = codec->startScanlineDecode(decodeInfo, nullptr, colorPtr, colorCountPtr); if (SkCodec::kSuccess != startResult) { SkDebugf("[terminated] Failed to restart scanline decoder with same parameters.\n"); return 9; } for (int i = 0; i < numStripes; i += 2) { // Read a stripe const int startY = i * stripeHeight; const int linesToRead = SkTMin(stripeHeight, height - startY); codec->getScanlines(bitmap.getAddr(0, startY), linesToRead, bitmap.rowBytes()); // Skip a stripe const int linesToSkip = SkTMin(stripeHeight, height - (i + 1) * stripeHeight); if (linesToSkip > 0) { codec->skipScanlines(linesToSkip); } } SkDebugf("[terminated] Success!\n"); break; } case 3: { //kSubset_Mode // Arbitrarily choose a divisor. int divisor = 2; // Total width/height of the image. const int W = codec->getInfo().width(); const int H = codec->getInfo().height(); if (divisor > W || divisor > H) { SkDebugf("[terminated] Cannot codec subset: divisor %d is too big " "with dimensions (%d x %d)\n", divisor, W, H); return 10; } // subset dimensions // SkWebpCodec, the only one that supports subsets, requires even top/left boundaries. const int w = SkAlign2(W / divisor); const int h = SkAlign2(H / divisor); SkIRect subset; SkCodec::Options opts; opts.fSubset = ⊂ SkBitmap subsetBm; // We will reuse pixel memory from bitmap. void* pixels = bitmap.getPixels(); // Keep track of left and top (for drawing subsetBm into canvas). We could use // fscale * x and fscale * y, but we want integers such that the next subset will start // where the last one ended. So we'll add decodeInfo.width() and height(). int left = 0; for (int x = 0; x < W; x += w) { int top = 0; for (int y = 0; y < H; y+= h) { // Do not make the subset go off the edge of the image. const int preScaleW = SkTMin(w, W - x); const int preScaleH = SkTMin(h, H - y); subset.setXYWH(x, y, preScaleW, preScaleH); // And fscale // FIXME: Should we have a version of getScaledDimensions that takes a subset // into account? decodeInfo = decodeInfo.makeWH( SkTMax(1, SkScalarRoundToInt(preScaleW * fscale)), SkTMax(1, SkScalarRoundToInt(preScaleH * fscale))); size_t rowBytes = decodeInfo.minRowBytes(); if (!subsetBm.installPixels(decodeInfo, pixels, rowBytes, colorTable.get(), nullptr, nullptr)) { SkDebugf("[terminated] Could not install pixels.\n"); return 11; } const SkCodec::Result result = codec->getPixels(decodeInfo, pixels, rowBytes, &opts, colorPtr, colorCountPtr); switch (result) { case SkCodec::kSuccess: case SkCodec::kIncompleteInput: SkDebugf("okay\n"); break; case SkCodec::kInvalidConversion: if (0 == (x|y)) { // First subset is okay to return unimplemented. SkDebugf("[terminated] Incompatible colortype conversion\n"); return 12; } // If the first subset succeeded, a later one should not fail. // fall through to failure case SkCodec::kUnimplemented: if (0 == (x|y)) { // First subset is okay to return unimplemented. SkDebugf("[terminated] subset codec not supported\n"); return 13; } // If the first subset succeeded, why would a later one fail? // fall through to failure default: SkDebugf("[terminated] subset codec failed to decode (%d, %d, %d, %d) " "with dimensions (%d x %d)\t error %d\n", x, y, decodeInfo.width(), decodeInfo.height(), W, H, result); return 14; } // translate by the scaled height. top += decodeInfo.height(); } // translate by the scaled width. left += decodeInfo.width(); } SkDebugf("[terminated] Success!\n"); break; } default: SkDebugf("[terminated] Mode not implemented yet\n"); } dump_png(bitmap); return 0; } int fuzz_skp(SkData* bytes) { SkMemoryStream stream(bytes); SkDebugf("Decoding\n"); SkAutoTUnref<SkPicture> pic(SkPicture::CreateFromStream(&stream)); if (!pic) { SkDebugf("[terminated] Couldn't decode as a picture.\n"); return 3; } SkDebugf("Rendering\n"); SkBitmap bitmap; if (!FLAGS_dump.isEmpty()) { SkIRect size = pic->cullRect().roundOut(); bitmap.allocN32Pixels(size.width(), size.height()); } SkCanvas canvas(bitmap); canvas.drawPicture(pic); SkDebugf("[terminated] Success! Decoded and rendered an SkPicture!\n"); dump_png(bitmap); return 0; } Fuzz::Fuzz(SkData* bytes) : fBytes(SkSafeRef(bytes)), fNextByte(0) {} void Fuzz::signalBug () { raise(SIGSEGV); } void Fuzz::signalBoring() { exit(0); } template <typename T> T Fuzz::nextT() { if (fNextByte + sizeof(T) > fBytes->size()) { this->signalBoring(); } T val; memcpy(&val, fBytes->bytes() + fNextByte, sizeof(T)); fNextByte += sizeof(T); return val; } uint8_t Fuzz::nextB() { return this->nextT<uint8_t >(); } bool Fuzz::nextBool() { return nextB()&1; } uint32_t Fuzz::nextU() { return this->nextT<uint32_t>(); } float Fuzz::nextF() { return this->nextT<float >(); } uint32_t Fuzz::nextRangeU(uint32_t min, uint32_t max) { if (min > max) { SkDebugf("Check mins and maxes (%d, %d)\n", min, max); this->signalBoring(); } uint32_t range = max - min + 1; if (0 == range) { return this->nextU(); } else { return min + this->nextU() % range; } } float Fuzz::nextRangeF(float min, float max) { if (min > max) { SkDebugf("Check mins and maxes (%f, %f)\n", min, max); this->signalBoring(); } float f = std::abs(this->nextF()); if (!std::isnormal(f) && f != 0.0) { this->signalBoring(); } return min + fmod(f, (max - min + 1)); }