text: // Copyright 2014 The Chromium 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 "chrome/common/safe_browsing/binary_feature_extractor.h"
  
  #include <stdint.h>
  #include <string.h>
  
  #include <memory>
  
  #include "base/base_paths.h"
  #include "base/files/file.h"
  #include "base/files/scoped_temp_dir.h"
  #include "base/path_service.h"
  #include "components/safe_browsing/core/common/proto/csd.pb.h"
  #include "crypto/sha2.h"
  #include "testing/gtest/include/gtest/gtest.h"
  
  namespace safe_browsing {
  
  class BinaryFeatureExtractorTest : public testing::Test {
   protected:
    BinaryFeatureExtractorTest() : extractor_(new BinaryFeatureExtractor()) {}
  
    void SetUp() override {
      ASSERT_TRUE(temp_dir_.CreateUniqueTempDir());
      path_ = temp_dir_.GetPath().Append(FILE_PATH_LITERAL("file.dll"));
    }
  
    // Writes |size| bytes from |data| to |path_|.
    void WriteFileToHash(const char* data, int size) {
      base::File file(path_, base::File::FLAG_CREATE | base::File::FLAG_WRITE);
      ASSERT_TRUE(file.IsValid());
      ASSERT_EQ(size, file.WriteAtCurrentPos(data, size));
    }
  
    // Verifies that |path_| hashes to |digest|.
    void ExpectFileDigestEq(const uint8_t* digest) {
      ClientDownloadRequest_Digests digests;
      extractor_->ExtractDigest(path_, &digests);
      EXPECT_TRUE(digests.has_sha256());
      EXPECT_EQ(std::string(reinterpret_cast<const char*>(digest),
                            crypto::kSHA256Length),
                digests.sha256());
    }
  
    static const int kBlockSize = 1 << 12;
    scoped_refptr<BinaryFeatureExtractor> extractor_;
    base::ScopedTempDir temp_dir_;
  
    // The path to a file that may be hashed.
    base::FilePath path_;
  };
  
  TEST_F(BinaryFeatureExtractorTest, ExtractDigestNoFile) {
    base::FilePath no_file =
        temp_dir_.GetPath().Append(FILE_PATH_LITERAL("does_not_exist.dll"));
  
    ClientDownloadRequest_Digests digests;
    extractor_->ExtractDigest(no_file, &digests);
    EXPECT_FALSE(digests.has_sha256());
  }
  
  // Hash a file that is less than 1 4k block.
  TEST_F(BinaryFeatureExtractorTest, ExtractSmallDigest) {
    static const uint8_t kDigest[] = {
        0x70, 0x27, 0x7b, 0xad, 0xfc, 0xb9, 0x97, 0x6b, 0x24, 0xf9, 0x80,
        0x22, 0x26, 0x2c, 0x31, 0xea, 0x8f, 0xb2, 0x1f, 0x54, 0x93, 0x6b,
        0x69, 0x8b, 0x5d, 0x54, 0xd4, 0xd4, 0x21, 0x0b, 0x98, 0xb7};
  
    static const char kFileData[] = {"The mountains are robotic."};
    static const int kDataLen = sizeof(kFileData) - 1;
    WriteFileToHash(kFileData, kDataLen);
    ExpectFileDigestEq(kDigest);
  }
  
  // Hash a file that is exactly 1 4k block.
  TEST_F(BinaryFeatureExtractorTest, ExtractOneBlockDigest) {
    static const uint8_t kDigest[] = {
        0x4f, 0x93, 0x6e, 0xee, 0x89, 0x55, 0xa5, 0xe7, 0x46, 0xd0, 0x61,
        0x43, 0x54, 0x5f, 0x33, 0x7b, 0xdc, 0x30, 0x3a, 0x4b, 0x18, 0xb4,
        0x82, 0x20, 0xe3, 0x93, 0x4c, 0x65, 0xe0, 0xc1, 0xc0, 0x19};
  
    const int kDataLen = kBlockSize;
    std::unique_ptr<char[]> data(new char[kDataLen]);
    memset(data.get(), 71, kDataLen);
    WriteFileToHash(data.get(), kDataLen);
    ExpectFileDigestEq(kDigest);
  }
  
  // Hash a file that is larger than 1 4k block.
  TEST_F(BinaryFeatureExtractorTest, ExtractBigBlockDigest) {
    static const uint8_t kDigest[] = {
        0xda, 0xae, 0xa0, 0xd5, 0x3b, 0xce, 0x0b, 0x4e, 0x5f, 0x5d, 0x0b,
        0xc7, 0x6a, 0x69, 0x0e, 0xf1, 0x8b, 0x2d, 0x20, 0xcd, 0xf2, 0x6d,
        0x33, 0xa7, 0x70, 0xf3, 0x6b, 0x85, 0xbf, 0xce, 0x9d, 0x5c};
  
    const int kDataLen = kBlockSize + 1;
    std::unique_ptr<char[]> data(new char[kDataLen]);
    memset(data.get(), 71, kDataLen);
    WriteFileToHash(data.get(), kDataLen);
    ExpectFileDigestEq(kDigest);
  }
  
  }  // namespace safe_browsing
  