chrome/common/safe_browsing/mach_o_image_reader_mac.h

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CHROME_COMMON_SAFE_BROWSING_MACH_O_IMAGE_READER_MAC_H_
   6 #define CHROME_COMMON_SAFE_BROWSING_MACH_O_IMAGE_READER_MAC_H_
   7
   8 #include <mach-o/loader.h>
   9 #include <stdint.h>
  10
  11 #include <vector>
  12
  13 #include "base/logging.h"
  14 #include "base/macros.h"
  15 #include "base/memory/scoped_ptr.h"
  16 #include "base/memory/scoped_vector.h"
  17
  18 namespace safe_browsing {
  19
  20 class ByteSlice;
  21
  22 // MachOImageReader is used to extract information about a Mach-O binary image.
  23 // This class supports fat and thin images. Initialize() must be called before
  24 // any other methods; if it returns false, it is illegal to call any other
  25 // methods on this class.
  26 class MachOImageReader {
  27  public:
  28   // Represents a Mach-O load command, including all of its data.
  29   struct LoadCommand {
  30     LoadCommand();
  31     ~LoadCommand();
  32
  33     uint32_t cmd() const {
  34       return as_command<load_command>()->cmd;
  35     }
  36
  37     uint32_t cmdsize() const {
  38       return as_command<load_command>()->cmdsize;
  39     }
  40
  41     template <typename T>
  42     const T* as_command() const {
  43       const T* command = reinterpret_cast<const T*>(&data[0]);
  44       if (data.size() < sizeof(T) || command->cmdsize < sizeof(T))
  45         return nullptr;
  46       return command;
  47     }
  48
  49     std::vector<uint8_t> data;
  50   };
  51
  52   // Returns true if |magic| is any Mach-O magic number. This can be used on the
  53   // first four bytes of a file (either in little- or big-endian) to quickly
  54   // determine whether or not the file is potentially a Mach-O file. An instance
  55   // of this class must be used for a true validity check.
  56   static bool IsMachOMagicValue(uint32_t magic);
  57
  58   MachOImageReader();
  59   ~MachOImageReader();
  60
  61   // Initializes the instance and verifies that the data is a valid Mach-O
  62   // image. This does not take ownership of the bytes, so the data must
  63   // remain valid for the lifetime of this object. Returns true if the
  64   // instance is initialized and valid, false if the file could not be parsed
  65   // as a Mach-O image.
  66   bool Initialize(const uint8_t* image, size_t image_size);
  67
  68   // Returns whether this is a fat Mach-O image. If this returns true, it is
  69   // only valid to call GetFatImages() and none of the other methods.
  70   bool IsFat();
  71
  72   // It is only valid to call this method if IsFat() returns true. This
  73   // returns an image reader for each architecture in the fat file.
  74   std::vector<MachOImageReader*> GetFatImages();
  75
  76   // Returns whether the image is a 64-bit image.
  77   bool Is64Bit();
  78
  79   // Retrieves the mach_header structure for the appropriate architecture.
  80   const mach_header* GetMachHeader();
  81   const mach_header_64* GetMachHeader64();
  82
  83   // Returns the Mach-O filetype field from the header.
  84   uint32_t GetFileType();
  85
  86   // Returns an array of all the load commands in the image.
  87   const std::vector<MachOImageReader::LoadCommand>& GetLoadCommands();
  88
  89   // If the image has a LC_CODE_SIGNATURE command, this retreives the code
  90   // signature blob in the __LINKEDIT segment.
  91   bool GetCodeSignatureInfo(std::vector<uint8_t>* info);
  92
  93  private:
  94   scoped_ptr<ByteSlice> data_;
  95
  96   bool is_fat_;
  97   ScopedVector<MachOImageReader> fat_images_;
  98
  99   bool is_64_bit_;
 100   std::vector<LoadCommand> commands_;
 101
 102   DISALLOW_COPY_AND_ASSIGN(MachOImageReader);
 103 };
 104
 105 }  // namespace safe_browsing
 106
 107 #endif  // CHROME_COMMON_SAFE_BROWSING_MACH_O_IMAGE_READER_MAC_H_