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author | sra@chromium.org <sra@chromium.org@0039d316-1c4b-4281-b951-d872f2087c98> | 2009-05-08 23:00:29 +0000 |
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committer | sra@chromium.org <sra@chromium.org@0039d316-1c4b-4281-b951-d872f2087c98> | 2009-05-08 23:00:29 +0000 |
commit | 04ca1bc65afb76ea30698c25f24599d20119e3d2 (patch) | |
tree | 2bb65e974d478f4d607b83f6a84a56c01f501ac0 /courgette/image_info.cc | |
parent | 9adf1dcf3281408560267787eddcc767566b425f (diff) | |
download | chromium_src-04ca1bc65afb76ea30698c25f24599d20119e3d2.zip chromium_src-04ca1bc65afb76ea30698c25f24599d20119e3d2.tar.gz chromium_src-04ca1bc65afb76ea30698c25f24599d20119e3d2.tar.bz2 |
Move Courgette
from src\third_party\courgette
to src\courgette and src\courgette\third_party
Fixed #includes
Added properties to ignore generated files:
C:\c5\src>svn pg svn:ignore courgette
courgette.xcodeproj
courgette.sln
courgette_fuzz.vcproj
courgette_lib.vcproj
courgette_minimal_tool.vcproj
courgette_tool.vcproj
courgette.vcproj
courgette_unittests.vcproj
SConstruct
courgette_fuzz.scons
courgette_lib.scons
courgette_main.scons
courgette_minimal_tool.scons
courgette.scons
courgette_tool.scons
courgette_unittests.scons
Review URL: http://codereview.chromium.org/115062
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@15692 0039d316-1c4b-4281-b951-d872f2087c98
Diffstat (limited to 'courgette/image_info.cc')
-rw-r--r-- | courgette/image_info.cc | 391 |
1 files changed, 391 insertions, 0 deletions
diff --git a/courgette/image_info.cc b/courgette/image_info.cc new file mode 100644 index 0000000..5651f36 --- /dev/null +++ b/courgette/image_info.cc @@ -0,0 +1,391 @@ +// 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 "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 |