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Diffstat (limited to 'third_party/courgette/image_info.cc')
-rw-r--r-- | third_party/courgette/image_info.cc | 392 |
1 files changed, 0 insertions, 392 deletions
diff --git a/third_party/courgette/image_info.cc b/third_party/courgette/image_info.cc deleted file mode 100644 index ca615dd..0000000 --- a/third_party/courgette/image_info.cc +++ /dev/null @@ -1,392 +0,0 @@ -// Copyright (c) 2009 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 "third_party/courgette/image_info.h" - -#include <memory.h> -#include <algorithm> -#include <map> -#include <set> -#include <sstream> -#include <vector> - -#include "base/logging.h" - -namespace courgette { - -std::string SectionName(const Section* section) { - if (section == NULL) - return "<none>"; - char name[9]; - memcpy(name, section->name, 8); - name[8] = '\0'; // Ensure termination. - return name; -} - -PEInfo::PEInfo() - : failure_reason_("uninitialized"), - start_(0), end_(0), length_(0), - is_PE32_plus_(0), file_length_(0), has_text_section_(false) { -} - -void PEInfo::Init(const void* start, size_t length) { - start_ = reinterpret_cast<const uint8*>(start); - length_ = length; - end_ = start_ + length_; - failure_reason_ = "unparsed"; -} - -// DescribeRVA is for debugging only. I would put it under #ifdef DEBUG except -// that during development I'm finding I need to call it when compiled in -// Release mode. Hence: -// TODO(sra): make this compile only for debug mode. -std::string PEInfo::DescribeRVA(RVA rva) const { - const Section* section = RVAToSection(rva); - std::ostringstream s; - s << std::hex << rva; - if (section) { - s << " ("; - s << SectionName(section) << "+" - << std::hex << (rva - section->virtual_address) - << ")"; - } - return s.str(); -} - -const Section* PEInfo::FindNextSection(uint32 fileOffset) const { - const Section* best = 0; - for (int i = 0; i < number_of_sections_; i++) { - const Section* section = §ions_[i]; - if (fileOffset <= section->file_offset_of_raw_data) { - if (best == 0 || - section->file_offset_of_raw_data < best->file_offset_of_raw_data) { - best = section; - } - } - } - return best; -} - -const Section* PEInfo::RVAToSection(RVA rva) const { - for (int i = 0; i < number_of_sections_; i++) { - const Section* section = §ions_[i]; - uint32 offset = rva - section->virtual_address; - if (offset < section->virtual_size) { - return section; - } - } - return NULL; -} - -int PEInfo::RVAToFileOffset(RVA rva) const { - const Section* section = RVAToSection(rva); - if (section) { - uint32 offset = rva - section->virtual_address; - if (offset < section->size_of_raw_data) { - return section->file_offset_of_raw_data + offset; - } else { - return kNoOffset; // In section but not in file (e.g. uninit data). - } - } - - // Small RVA values point into the file header in the loaded image. - // RVA 0 is the module load address which Windows uses as the module handle. - // RVA 2 sometimes occurs, I'm not sure what it is, but it would map into the - // DOS header. - if (rva == 0 || rva == 2) - return rva; - - NOTREACHED(); - return kNoOffset; -} - -const uint8* PEInfo::RVAToPointer(RVA rva) const { - int file_offset = RVAToFileOffset(rva); - if (file_offset == kNoOffset) - return NULL; - else - return start_ + file_offset; -} - -RVA PEInfo::FileOffsetToRVA(uint32 file_offset) const { - for (int i = 0; i < number_of_sections_; i++) { - const Section* section = §ions_[i]; - uint32 offset = file_offset - section->file_offset_of_raw_data; - if (offset < section->size_of_raw_data) { - return section->virtual_address + offset; - } - } - return 0; -} - -//////////////////////////////////////////////////////////////////////////////// - -namespace { - -// Constants and offsets gleaned from WINNT.H and various articles on the -// format of Windows PE executables. - -// This is FIELD_OFFSET(IMAGE_DOS_HEADER, e_lfanew): -const size_t kOffsetOfFileAddressOfNewExeHeader = 0x3c; - -const uint16 kImageNtOptionalHdr32Magic = 0x10b; -const uint16 kImageNtOptionalHdr64Magic = 0x20b; - -const size_t kSizeOfCoffHeader = 20; -const size_t kOffsetOfDataDirectoryFromImageOptionalHeader32 = 96; -const size_t kOffsetOfDataDirectoryFromImageOptionalHeader64 = 112; - -// These helper functions avoid the need for casts in the main code. -inline uint16 ReadU16(const uint8* address, size_t offset) { - return *reinterpret_cast<const uint16*>(address + offset); -} - -inline uint32 ReadU32(const uint8* address, size_t offset) { - return *reinterpret_cast<const uint32*>(address + offset); -} - -inline uint64 ReadU64(const uint8* address, size_t offset) { - return *reinterpret_cast<const uint64*>(address + offset); -} - -} // namespace - -// ParseHeader attempts to match up the buffer with the Windows data -// structures that exist within a Windows 'Portable Executable' format file. -// Returns 'true' if the buffer matches, and 'false' if the data looks -// suspicious. Rather than try to 'map' the buffer to the numerous windows -// structures, we extract the information we need into the courgette::PEInfo -// structure. -// -bool PEInfo::ParseHeader() { - if (length_ < kOffsetOfFileAddressOfNewExeHeader + 4 /*size*/) - return Bad("Too small"); - - // Have 'MZ' magic for a DOS header? - if (start_[0] != 'M' || start_[1] != 'Z') - return Bad("Not MZ"); - - // offset from DOS header to PE header is stored in DOS header. - uint32 offset = ReadU32(start_, kOffsetOfFileAddressOfNewExeHeader); - - const uint8* const pe_header = start_ + offset; - const size_t kMinPEHeaderSize = 4 /*signature*/ + kSizeOfCoffHeader; - if (pe_header <= start_ || pe_header >= end_ - kMinPEHeaderSize) - return Bad("Bad offset to PE header"); - - if (offset % 8 != 0) - return Bad("Misaligned PE header"); - - // The 'PE' header is an IMAGE_NT_HEADERS structure as defined in WINNT.H. - // See http://msdn.microsoft.com/en-us/library/ms680336(VS.85).aspx - // - // The first field of the IMAGE_NT_HEADERS is the signature. - if (!(pe_header[0] == 'P' && - pe_header[1] == 'E' && - pe_header[2] == 0 && - pe_header[3] == 0)) - return Bad("no PE signature"); - - // The second field of the IMAGE_NT_HEADERS is the COFF header. - // The COFF header is also called an IMAGE_FILE_HEADER - // http://msdn.microsoft.com/en-us/library/ms680313(VS.85).aspx - const uint8* const coff_header = pe_header + 4; - machine_type_ = ReadU16(coff_header, 0); - number_of_sections_ = ReadU16(coff_header, 2); - size_of_optional_header_ = ReadU16(coff_header, 16); - - // The rest of the IMAGE_NT_HEADERS is the IMAGE_OPTIONAL_HEADER(32|64) - const uint8* const optional_header = coff_header + kSizeOfCoffHeader; - optional_header_ = optional_header; - - if (optional_header + size_of_optional_header_ >= end_) - return Bad("optional header past end of file"); - - // Check we can read the magic. - if (size_of_optional_header_ < 2) - return Bad("optional header no magic"); - - uint16 magic = ReadU16(optional_header, 0); - - if (magic == kImageNtOptionalHdr32Magic) { - is_PE32_plus_ = false; - offset_of_data_directories_ = - kOffsetOfDataDirectoryFromImageOptionalHeader32; - } else if (magic == kImageNtOptionalHdr64Magic) { - is_PE32_plus_ = true; - offset_of_data_directories_ = - kOffsetOfDataDirectoryFromImageOptionalHeader64; - } else { - return Bad("unrecognized magic"); - } - - // Check that we can read the rest of the the fixed fields. Data directories - // directly follow the fixed fields of the IMAGE_OPTIONAL_HEADER. - if (size_of_optional_header_ < offset_of_data_directories_) - return Bad("optional header too short"); - - // The optional header is either an IMAGE_OPTIONAL_HEADER32 or - // IMAGE_OPTIONAL_HEADER64 - // http://msdn.microsoft.com/en-us/library/ms680339(VS.85).aspx - // - // Copy the fields we care about. - size_of_code_ = ReadU32(optional_header, 4); - size_of_initialized_data_ = ReadU32(optional_header, 8); - size_of_uninitialized_data_ = ReadU32(optional_header, 12); - base_of_code_ = ReadU32(optional_header, 20); - if (is_PE32_plus_) { - base_of_data_ = 0; - image_base_ = ReadU64(optional_header, 24); - } else { - base_of_data_ = ReadU32(optional_header, 24); - image_base_ = ReadU32(optional_header, 28); - } - size_of_image_ = ReadU32(optional_header, 56); - number_of_data_directories_ = - ReadU32(optional_header, (is_PE32_plus_ ? 108 : 92)); - - if (size_of_code_ >= length_ || - size_of_initialized_data_ >= length_ || - size_of_code_ + size_of_initialized_data_ >= length_) { - // This validation fires on some perfectly fine executables. - // return Bad("code or initialized data too big"); - } - - // TODO(sra): we can probably get rid of most of the data directories. - bool b = true; - // 'b &= ...' could be short circuit 'b = b && ...' but it is not necessary - // for correctness and it compiles smaller this way. - b &= ReadDataDirectory(0, &export_table_); - b &= ReadDataDirectory(1, &import_table_); - b &= ReadDataDirectory(2, &resource_table_); - b &= ReadDataDirectory(3, &exception_table_); - b &= ReadDataDirectory(5, &base_relocation_table_); - b &= ReadDataDirectory(11, &bound_import_table_); - b &= ReadDataDirectory(12, &import_address_table_); - b &= ReadDataDirectory(13, &delay_import_descriptor_); - b &= ReadDataDirectory(14, &clr_runtime_header_); - if (!b) { - return Bad("malformed data directory"); - } - - // Sections follow the optional header. - sections_ = - reinterpret_cast<const Section*>(optional_header + - size_of_optional_header_); - file_length_ = 0; - - for (int i = 0; i < number_of_sections_; ++i) { - const Section* section = §ions_[i]; - - // TODO(sra): consider using the 'characteristics' field of the section - // header to see if the section contains instructions. - if (memcmp(section->name, ".text", 6) == 0) - has_text_section_ = true; - - uint32 section_end = - section->file_offset_of_raw_data + section->size_of_raw_data; - if (section_end > file_length_) - file_length_ = section_end; - } - - failure_reason_ = NULL; - return true; -} - -bool PEInfo::ReadDataDirectory(int index, ImageDataDirectory* directory) { - if (index < number_of_data_directories_) { - size_t offset = index * 8 + offset_of_data_directories_; - if (offset >= size_of_optional_header_) - return Bad("number of data directories inconsistent"); - const uint8* data_directory = optional_header_ + offset; - if (data_directory < start_ || data_directory + 8 >= end_) - return Bad("data directory outside image"); - RVA rva = ReadU32(data_directory, 0); - size_t size = ReadU32(data_directory, 4); - if (size > size_of_image_) - return Bad("data directory size too big"); - - // TODO(sra): validate RVA. - directory->address_ = rva; - directory->size_ = size; - return true; - } else { - directory->address_ = 0; - directory->size_ = 0; - return true; - } -} - -bool PEInfo::Bad(const char* reason) { - failure_reason_ = reason; - return false; -} - -//////////////////////////////////////////////////////////////////////////////// - -bool PEInfo::ParseRelocs(std::vector<RVA> *relocs) { - relocs->clear(); - - size_t relocs_size = base_relocation_table_.size_; - if (relocs_size == 0) - return true; - - // The format of the base relocation table is a sequence of variable sized - // IMAGE_BASE_RELOCATION blocks. Search for - // "The format of the base relocation data is somewhat quirky" - // at http://msdn.microsoft.com/en-us/library/ms809762.aspx - - const uint8* start = RVAToPointer(base_relocation_table_.address_); - const uint8* end = start + relocs_size; - - // Make sure entire base relocation table is within the buffer. - if (start < start_ || - start >= end_ || - end <= start_ || - end > end_) { - return Bad(".relocs outside image"); - } - - const uint8* block = start; - - // Walk the variable sized blocks. - while (block + 8 < end) { - RVA page_rva = ReadU32(block, 0); - uint32 size = ReadU32(block, 4); - if (size < 8 || // Size includes header ... - size % 4 != 0) // ... and is word aligned. - return Bad("unreasonable relocs block"); - - const uint8* end_entries = block + size; - - if (end_entries <= block || end_entries <= start_ || end_entries > end_) - return Bad(".relocs block outside image"); - - // Walk through the two-byte entries. - for (const uint8* p = block + 8; p < end_entries; p += 2) { - uint16 entry = ReadU16(p, 0); - int type = entry >> 12; - int offset = entry & 0xFFF; - - RVA rva = page_rva + offset; - if (type == 3) { // IMAGE_REL_BASED_HIGHLOW - relocs->push_back(rva); - } else if (type == 0) { // IMAGE_REL_BASED_ABSOLUTE - // Ignore, used as padding. - } else { - // Does not occur in Windows x86 executables. - return Bad("unknown type of reloc"); - } - } - - block += size; - } - - std::sort(relocs->begin(), relocs->end()); - - return true; -} - -} // namespace courgette - |