1 files changed, 327 insertions, 0 deletions

diff --git a/chrome/browser/safe_browsing/pe_image_reader_win.cc b/chrome/browser/safe_browsing/pe_image_reader_win.cc
new file mode 100644
index 0000000..70734fdb
--- /dev/null
+++ b/chrome/browser/safe_browsing/pe_image_reader_win.cc
@@ -0,0 +1,327 @@
+// 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/browser/safe_browsing/pe_image_reader_win.h"
+
+#include "base/logging.h"
+
+namespace safe_browsing {
+
+// A class template of traits pertaining to IMAGE_OPTIONAL_HEADER{32,64}.
+template<class HEADER_TYPE>
+struct OptionalHeaderTraits {
+};
+
+template<>
+struct OptionalHeaderTraits<IMAGE_OPTIONAL_HEADER32> {
+  static const PeImageReader::WordSize word_size = PeImageReader::WORD_SIZE_32;
+};
+
+template<>
+struct OptionalHeaderTraits<IMAGE_OPTIONAL_HEADER64> {
+  static const PeImageReader::WordSize word_size = PeImageReader::WORD_SIZE_64;
+};
+
+// A template for type-specific optional header implementations. This, in
+// conjunction with the OptionalHeader interface, effectively erases the
+// underlying structure type from the point of view of the PeImageReader.
+template<class OPTIONAL_HEADER_TYPE>
+class PeImageReader::OptionalHeaderImpl : public PeImageReader::OptionalHeader {
+ public:
+  typedef OptionalHeaderTraits<OPTIONAL_HEADER_TYPE> TraitsType;
+
+  explicit OptionalHeaderImpl(const uint8_t* optional_header_start)
+      : optional_header_(reinterpret_cast<const OPTIONAL_HEADER_TYPE*>(
+                             optional_header_start)) {}
+
+  virtual WordSize GetWordSize() OVERRIDE {
+    return TraitsType::word_size;
+  }
+
+  virtual size_t GetDataDirectoryOffset() OVERRIDE {
+    return offsetof(OPTIONAL_HEADER_TYPE, DataDirectory);
+  }
+
+  virtual DWORD GetDataDirectorySize() OVERRIDE {
+    return optional_header_->NumberOfRvaAndSizes;
+  }
+
+  virtual const IMAGE_DATA_DIRECTORY* GetDataDirectoryEntries() OVERRIDE {
+    return &optional_header_->DataDirectory[0];
+  }
+
+ private:
+  const OPTIONAL_HEADER_TYPE* optional_header_;
+  DISALLOW_COPY_AND_ASSIGN(OptionalHeaderImpl);
+};
+
+PeImageReader::PeImageReader()
+    : image_data_(),
+      image_size_(),
+      validation_state_() {}
+
+PeImageReader::~PeImageReader() {
+  Clear();
+}
+
+bool PeImageReader::Initialize(const uint8_t* image_data, size_t image_size) {
+  image_data_ = image_data;
+  image_size_ = image_size;
+
+  if (!ValidateDosHeader() ||
+      !ValidatePeSignature() ||
+      !ValidateCoffFileHeader() ||
+      !ValidateOptionalHeader() ||
+      !ValidateSectionHeaders()) {
+    Clear();
+    return false;
+  }
+
+  return true;
+}
+
+PeImageReader::WordSize PeImageReader::GetWordSize() {
+  return optional_header_->GetWordSize();
+}
+
+const IMAGE_DOS_HEADER* PeImageReader::GetDosHeader() {
+  DCHECK_NE((validation_state_ & VALID_DOS_HEADER), 0U);
+  return reinterpret_cast<const IMAGE_DOS_HEADER*>(image_data_);
+}
+
+const IMAGE_FILE_HEADER* PeImageReader::GetCoffFileHeader() {
+  DCHECK_NE((validation_state_ & VALID_COFF_FILE_HEADER), 0U);
+  return reinterpret_cast<const IMAGE_FILE_HEADER*>(
+      image_data_ + GetDosHeader()->e_lfanew + sizeof(DWORD));
+}
+
+const uint8_t* PeImageReader::GetOptionalHeaderData(
+    size_t* optional_header_size) {
+  *optional_header_size = GetOptionalHeaderSize();
+  return GetOptionalHeaderStart();
+}
+
+size_t PeImageReader::GetNumberOfSections() {
+  return GetCoffFileHeader()->NumberOfSections;
+}
+
+const IMAGE_SECTION_HEADER* PeImageReader::GetSectionHeaderAt(size_t index) {
+  DCHECK_NE((validation_state_ & VALID_SECTION_HEADERS), 0U);
+  DCHECK_LT(index, GetNumberOfSections());
+  return reinterpret_cast<const IMAGE_SECTION_HEADER*>(
+      GetOptionalHeaderStart() +
+      GetOptionalHeaderSize() +
+      (sizeof(IMAGE_SECTION_HEADER) * index));
+}
+
+const uint8_t* PeImageReader::GetExportSection(size_t* section_size) {
+  size_t data_size = 0;
+  const uint8_t* data = GetImageData(IMAGE_DIRECTORY_ENTRY_EXPORT, &data_size);
+
+  // The export section data must be big enough for the export directory.
+  if (!data || data_size < sizeof(IMAGE_EXPORT_DIRECTORY))
+    return NULL;
+
+  *section_size = data_size;
+  return data;
+}
+
+size_t PeImageReader::GetNumberOfDebugEntries() {
+  size_t data_size = 0;
+  const uint8_t* data = GetImageData(IMAGE_DIRECTORY_ENTRY_DEBUG, &data_size);
+  return data ? (data_size / sizeof(IMAGE_DEBUG_DIRECTORY)) : 0;
+}
+
+const IMAGE_DEBUG_DIRECTORY* PeImageReader::GetDebugEntry(
+    size_t index,
+    const uint8_t** raw_data,
+    size_t* raw_data_size) {
+  DCHECK_LT(index, GetNumberOfDebugEntries());
+
+  // Get the debug directory.
+  size_t debug_directory_size = 0;
+  const IMAGE_DEBUG_DIRECTORY* entries =
+      reinterpret_cast<const IMAGE_DEBUG_DIRECTORY*>(
+          GetImageData(IMAGE_DIRECTORY_ENTRY_DEBUG, &debug_directory_size));
+  if (!entries)
+    return NULL;
+
+  const IMAGE_DEBUG_DIRECTORY& entry = entries[index];
+  const uint8_t* debug_data = NULL;
+  if (GetStructureAt(entry.PointerToRawData, entry.SizeOfData, &debug_data)) {
+    *raw_data = debug_data;
+    *raw_data_size = entry.SizeOfData;
+  }
+  return &entry;
+}
+
+void PeImageReader::Clear() {
+  image_data_ = NULL;
+  image_size_ = 0;
+  validation_state_ = 0;
+  optional_header_.reset();
+}
+
+bool PeImageReader::ValidateDosHeader() {
+  const IMAGE_DOS_HEADER* dos_header = NULL;
+  if (!GetStructureAt(0, &dos_header) ||
+      dos_header->e_magic != IMAGE_DOS_SIGNATURE ||
+      dos_header->e_lfanew < 0) {
+    return false;
+  }
+
+  validation_state_ |= VALID_DOS_HEADER;
+  return true;
+}
+
+bool PeImageReader::ValidatePeSignature() {
+  const DWORD* signature = NULL;
+  if (!GetStructureAt(GetDosHeader()->e_lfanew, &signature) ||
+      *signature != IMAGE_NT_SIGNATURE) {
+    return false;
+  }
+
+  validation_state_ |= VALID_PE_SIGNATURE;
+  return true;
+}
+
+bool PeImageReader::ValidateCoffFileHeader() {
+  DCHECK_NE((validation_state_ & VALID_PE_SIGNATURE), 0U);
+  const IMAGE_FILE_HEADER* file_header = NULL;
+  if (!GetStructureAt(GetDosHeader()->e_lfanew +
+                          offsetof(IMAGE_NT_HEADERS32, FileHeader),
+                      &file_header)) {
+    return false;
+  }
+
+  validation_state_ |= VALID_COFF_FILE_HEADER;
+  return true;
+}
+
+bool PeImageReader::ValidateOptionalHeader() {
+  const IMAGE_FILE_HEADER* file_header = GetCoffFileHeader();
+  const size_t optional_header_offset =
+      GetDosHeader()->e_lfanew + offsetof(IMAGE_NT_HEADERS32, OptionalHeader);
+  const size_t optional_header_size = file_header->SizeOfOptionalHeader;
+  const WORD* optional_header_magic = NULL;
+
+  if (optional_header_size < sizeof(*optional_header_magic) ||
+      !GetStructureAt(optional_header_offset, &optional_header_magic)) {
+    return false;
+  }
+
+  scoped_ptr<OptionalHeader> optional_header;
+  if (*optional_header_magic == IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
+    optional_header.reset(new OptionalHeaderImpl<IMAGE_OPTIONAL_HEADER32>(
+        image_data_ + optional_header_offset));
+  } else if (*optional_header_magic == IMAGE_NT_OPTIONAL_HDR64_MAGIC) {
+    optional_header.reset(new OptionalHeaderImpl<IMAGE_OPTIONAL_HEADER64>(
+        image_data_ + optional_header_offset));
+  } else {
+    return false;
+  }
+
+  // Does all of the claimed optional header fit in the image?
+  if (optional_header_size > image_size_ - optional_header_offset)
+    return false;
+
+  // Is the claimed optional header big enough for everything but the dir?
+  if (optional_header->GetDataDirectoryOffset() > optional_header_size)
+    return false;
+
+  // Is there enough room for all of the claimed directory entries?
+  if (optional_header->GetDataDirectorySize() >
+      ((optional_header_size - optional_header->GetDataDirectoryOffset()) /
+       sizeof(IMAGE_DATA_DIRECTORY))) {
+    return false;
+  }
+
+  optional_header_.swap(optional_header);
+  validation_state_ |= VALID_OPTIONAL_HEADER;
+  return true;
+}
+
+bool PeImageReader::ValidateSectionHeaders() {
+  const uint8_t* first_section_header =
+      GetOptionalHeaderStart() + GetOptionalHeaderSize();
+  const size_t number_of_sections = GetNumberOfSections();
+
+  // Do all section headers fit in the image?
+  if (!GetStructureAt(first_section_header - image_data_,
+                      number_of_sections * sizeof(IMAGE_SECTION_HEADER),
+                      &first_section_header)) {
+    return false;
+  }
+
+  validation_state_ |= VALID_SECTION_HEADERS;
+  return true;
+}
+
+const uint8_t* PeImageReader::GetOptionalHeaderStart() {
+  DCHECK_NE((validation_state_ & VALID_OPTIONAL_HEADER), 0U);
+  return (image_data_ +
+          GetDosHeader()->e_lfanew +
+          offsetof(IMAGE_NT_HEADERS32, OptionalHeader));
+}
+
+size_t PeImageReader::GetOptionalHeaderSize() {
+  return GetCoffFileHeader()->SizeOfOptionalHeader;
+}
+
+const IMAGE_DATA_DIRECTORY* PeImageReader::GetDataDirectoryEntryAt(
+    size_t index) {
+  DCHECK_NE((validation_state_ & VALID_OPTIONAL_HEADER), 0U);
+  if (index >= optional_header_->GetDataDirectorySize())
+    return NULL;
+  return &optional_header_->GetDataDirectoryEntries()[index];
+}
+
+const IMAGE_SECTION_HEADER* PeImageReader::FindSectionFromRva(
+    uint32_t relative_address) {
+  const size_t number_of_sections = GetNumberOfSections();
+  for (size_t i = 0; i < number_of_sections; ++i) {
+    const IMAGE_SECTION_HEADER* section_header = GetSectionHeaderAt(i);
+    // Is the raw data present in the image? If no, optimistically keep looking.
+    const uint8_t* section_data = NULL;
+    if (!GetStructureAt(section_header->PointerToRawData,
+                        section_header->SizeOfRawData,
+                        &section_data)) {
+      continue;
+    }
+    // Does the RVA lie on or after this section's start when mapped? If no,
+    // bail.
+    if (section_header->VirtualAddress > relative_address)
+      break;
+    // Does the RVA lie within the section when mapped? If no, keep looking.
+    size_t address_offset = relative_address - section_header->VirtualAddress;
+    if (address_offset > section_header->Misc.VirtualSize)
+      continue;
+    // We have a winner.
+    return section_header;
+  }
+  return NULL;
+}
+
+const uint8_t* PeImageReader::GetImageData(size_t index, size_t* data_length) {
+  // Get the directory entry for the debug data.
+  const IMAGE_DATA_DIRECTORY* entry = GetDataDirectoryEntryAt(index);
+  if (!entry)
+    return NULL;
+
+  // Find the section containing the data.
+  const IMAGE_SECTION_HEADER* header =
+      FindSectionFromRva(entry->VirtualAddress);
+  if (!header)
+    return NULL;
+
+  // Does the data fit within the section when mapped?
+  size_t data_offset = entry->VirtualAddress - header->VirtualAddress;
+  if (entry->Size > (header->Misc.VirtualSize - data_offset))
+    return NULL;
+
+  *data_length = entry->Size;
+  return image_data_ + header->PointerToRawData + data_offset;
+}
+
+}  // namespace safe_browsing