etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 1 | // Copyright 2016 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 | #include "courgette/disassembler_win32.h" |
| 6 | |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 7 | #include <algorithm> |
| 8 | |
huangs | 7b221a5 | 2016-11-09 22:28:23 | [diff] [blame] | 9 | #include "base/bind.h" |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 10 | #include "base/logging.h" |
| 11 | #include "courgette/assembly_program.h" |
| 12 | #include "courgette/courgette.h" |
| 13 | |
| 14 | #if COURGETTE_HISTOGRAM_TARGETS |
| 15 | #include <iostream> |
| 16 | #endif |
| 17 | |
| 18 | namespace courgette { |
| 19 | |
etiennep | 5059bca | 2016-07-08 17:55:20 | [diff] [blame] | 20 | DisassemblerWin32::DisassemblerWin32(const uint8_t* start, size_t length) |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 21 | : Disassembler(start, length) {} |
| 22 | |
| 23 | RVA DisassemblerWin32::FileOffsetToRVA(FileOffset file_offset) const { |
| 24 | for (int i = 0; i < number_of_sections_; ++i) { |
| 25 | const Section* section = §ions_[i]; |
| 26 | if (file_offset >= section->file_offset_of_raw_data) { |
| 27 | FileOffset offset_in_section = |
| 28 | file_offset - section->file_offset_of_raw_data; |
| 29 | if (offset_in_section < section->size_of_raw_data) |
| 30 | return static_cast<RVA>(section->virtual_address + offset_in_section); |
| 31 | } |
| 32 | } |
| 33 | |
| 34 | NOTREACHED(); |
| 35 | return kNoRVA; |
| 36 | } |
| 37 | |
| 38 | FileOffset DisassemblerWin32::RVAToFileOffset(RVA rva) const { |
| 39 | const Section* section = RVAToSection(rva); |
| 40 | if (section != nullptr) { |
| 41 | FileOffset offset_in_section = rva - section->virtual_address; |
| 42 | // Need this extra check, since an |rva| may be valid for a section, but is |
| 43 | // non-existent in an image (e.g. uninit data). |
| 44 | if (offset_in_section >= section->size_of_raw_data) |
| 45 | return kNoFileOffset; |
| 46 | |
| 47 | return static_cast<FileOffset>(section->file_offset_of_raw_data + |
| 48 | offset_in_section); |
| 49 | } |
| 50 | |
| 51 | // Small RVA values point into the file header in the loaded image. |
| 52 | // RVA 0 is the module load address which Windows uses as the module handle. |
| 53 | // RVA 2 sometimes occurs, I'm not sure what it is, but it would map into the |
| 54 | // DOS header. |
| 55 | if (rva == 0 || rva == 2) |
| 56 | return static_cast<FileOffset>(rva); |
| 57 | |
| 58 | NOTREACHED(); |
| 59 | return kNoFileOffset; |
| 60 | } |
| 61 | |
| 62 | // ParseHeader attempts to match up the buffer with the Windows data |
| 63 | // structures that exist within a Windows 'Portable Executable' format file. |
| 64 | // Returns 'true' if the buffer matches, and 'false' if the data looks |
| 65 | // suspicious. Rather than try to 'map' the buffer to the numerous windows |
| 66 | // structures, we extract the information we need into the courgette::PEInfo |
| 67 | // structure. |
| 68 | // |
| 69 | bool DisassemblerWin32::ParseHeader() { |
Samuel Huang | a34dce5 | 2019-04-03 15:53:13 | [diff] [blame] | 70 | if (!IsRangeInBounds(kOffsetOfFileAddressOfNewExeHeader, 4)) |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 71 | return Bad("Too small"); |
| 72 | |
| 73 | // Have 'MZ' magic for a DOS header? |
| 74 | if (start()[0] != 'M' || start()[1] != 'Z') |
| 75 | return Bad("Not MZ"); |
| 76 | |
| 77 | // offset from DOS header to PE header is stored in DOS header. |
Samuel Huang | a34dce5 | 2019-04-03 15:53:13 | [diff] [blame] | 78 | FileOffset pe_header_offset = static_cast<FileOffset>( |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 79 | ReadU32(start(), kOffsetOfFileAddressOfNewExeHeader)); |
Samuel Huang | a34dce5 | 2019-04-03 15:53:13 | [diff] [blame] | 80 | if (pe_header_offset % 8 != 0) |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 81 | return Bad("Misaligned PE header"); |
Samuel Huang | a34dce5 | 2019-04-03 15:53:13 | [diff] [blame] | 82 | if (pe_header_offset < kOffsetOfFileAddressOfNewExeHeader + 4) |
| 83 | return Bad("PE header pathological overlap"); |
| 84 | if (!IsRangeInBounds(pe_header_offset, kMinPeHeaderSize)) |
| 85 | return Bad("PE header past end of file"); |
| 86 | |
| 87 | const uint8_t* const pe_header = FileOffsetToPointer(pe_header_offset); |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 88 | |
| 89 | // The 'PE' header is an IMAGE_NT_HEADERS structure as defined in WINNT.H. |
| 90 | // See http://msdn.microsoft.com/en-us/library/ms680336(VS.85).aspx |
| 91 | // |
| 92 | // The first field of the IMAGE_NT_HEADERS is the signature. |
| 93 | if (!(pe_header[0] == 'P' && pe_header[1] == 'E' && pe_header[2] == 0 && |
Samuel Huang | a34dce5 | 2019-04-03 15:53:13 | [diff] [blame] | 94 | pe_header[3] == 0)) { |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 95 | return Bad("No PE signature"); |
Samuel Huang | a34dce5 | 2019-04-03 15:53:13 | [diff] [blame] | 96 | } |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 97 | |
| 98 | // The second field of the IMAGE_NT_HEADERS is the COFF header. |
| 99 | // The COFF header is also called an IMAGE_FILE_HEADER |
| 100 | // http://msdn.microsoft.com/en-us/library/ms680313(VS.85).aspx |
Samuel Huang | a34dce5 | 2019-04-03 15:53:13 | [diff] [blame] | 101 | FileOffset coff_header_offset = pe_header_offset + 4; |
| 102 | if (!IsRangeInBounds(coff_header_offset, kSizeOfCoffHeader)) |
| 103 | return Bad("COFF header past end of file"); |
| 104 | const uint8_t* const coff_header = start() + coff_header_offset; |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 105 | machine_type_ = ReadU16(coff_header, 0); |
| 106 | number_of_sections_ = ReadU16(coff_header, 2); |
| 107 | size_of_optional_header_ = ReadU16(coff_header, 16); |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 108 | // Check we can read the magic. |
| 109 | if (size_of_optional_header_ < 2) |
| 110 | return Bad("Optional header no magic"); |
Samuel Huang | a34dce5 | 2019-04-03 15:53:13 | [diff] [blame] | 111 | // Check that we can read the rest of the the fixed fields. Data directories |
| 112 | // directly follow the fixed fields of the IMAGE_OPTIONAL_HEADER. |
| 113 | if (size_of_optional_header_ < RelativeOffsetOfDataDirectories()) |
| 114 | return Bad("Optional header too short"); |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 115 | |
Samuel Huang | a34dce5 | 2019-04-03 15:53:13 | [diff] [blame] | 116 | // The rest of the IMAGE_NT_HEADERS is the IMAGE_OPTIONAL_HEADER(32|64) |
| 117 | FileOffset optional_header_offset = pe_header_offset + kMinPeHeaderSize; |
| 118 | if (!IsRangeInBounds(optional_header_offset, size_of_optional_header_)) |
| 119 | return Bad("Optional header past end of file"); |
| 120 | optional_header_ = start() + optional_header_offset; |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 121 | |
Samuel Huang | a34dce5 | 2019-04-03 15:53:13 | [diff] [blame] | 122 | uint16_t magic = ReadU16(optional_header_, 0); |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 123 | switch (kind()) { |
| 124 | case EXE_WIN_32_X86: |
Samuel Huang | a34dce5 | 2019-04-03 15:53:13 | [diff] [blame] | 125 | if (magic != kImageNtOptionalHdr32Magic) |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 126 | return Bad("64 bit executables are not supported by this disassembler"); |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 127 | break; |
| 128 | |
| 129 | case EXE_WIN_32_X64: |
Samuel Huang | a34dce5 | 2019-04-03 15:53:13 | [diff] [blame] | 130 | if (magic != kImageNtOptionalHdr64Magic) |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 131 | return Bad("32 bit executables are not supported by this disassembler"); |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 132 | break; |
| 133 | |
| 134 | default: |
| 135 | return Bad("Unrecognized magic"); |
| 136 | } |
| 137 | |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 138 | // The optional header is either an IMAGE_OPTIONAL_HEADER32 or |
| 139 | // IMAGE_OPTIONAL_HEADER64 |
| 140 | // http://msdn.microsoft.com/en-us/library/ms680339(VS.85).aspx |
| 141 | // |
| 142 | // Copy the fields we care about. |
Samuel Huang | a34dce5 | 2019-04-03 15:53:13 | [diff] [blame] | 143 | size_of_code_ = ReadU32(optional_header_, 4); |
| 144 | size_of_initialized_data_ = ReadU32(optional_header_, 8); |
| 145 | size_of_uninitialized_data_ = ReadU32(optional_header_, 12); |
| 146 | base_of_code_ = ReadU32(optional_header_, 20); |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 147 | |
| 148 | switch (kind()) { |
| 149 | case EXE_WIN_32_X86: |
Samuel Huang | a34dce5 | 2019-04-03 15:53:13 | [diff] [blame] | 150 | base_of_data_ = ReadU32(optional_header_, 24); |
| 151 | image_base_ = ReadU32(optional_header_, 28); |
| 152 | size_of_image_ = ReadU32(optional_header_, 56); |
| 153 | number_of_data_directories_ = ReadU32(optional_header_, 92); |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 154 | break; |
| 155 | |
| 156 | case EXE_WIN_32_X64: |
| 157 | base_of_data_ = 0; |
Samuel Huang | a34dce5 | 2019-04-03 15:53:13 | [diff] [blame] | 158 | image_base_ = ReadU64(optional_header_, 24); |
| 159 | size_of_image_ = ReadU32(optional_header_, 56); |
| 160 | number_of_data_directories_ = ReadU32(optional_header_, 108); |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 161 | break; |
| 162 | |
| 163 | default: |
| 164 | NOTREACHED(); |
| 165 | } |
| 166 | |
Samuel Huang | a34dce5 | 2019-04-03 15:53:13 | [diff] [blame] | 167 | if (size_of_image_ >= 0x80000000U) |
| 168 | return Bad("Invalid SizeOfImage"); |
| 169 | |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 170 | if (size_of_code_ >= length() || size_of_initialized_data_ >= length() || |
| 171 | size_of_code_ + size_of_initialized_data_ >= length()) { |
| 172 | // This validation fires on some perfectly fine executables. |
| 173 | // return Bad("code or initialized data too big"); |
| 174 | } |
| 175 | |
| 176 | // TODO(sra): we can probably get rid of most of the data directories. |
| 177 | bool b = true; |
| 178 | // 'b &= ...' could be short circuit 'b = b && ...' but it is not necessary |
| 179 | // for correctness and it compiles smaller this way. |
| 180 | b &= ReadDataDirectory(0, &export_table_); |
| 181 | b &= ReadDataDirectory(1, &import_table_); |
| 182 | b &= ReadDataDirectory(2, &resource_table_); |
| 183 | b &= ReadDataDirectory(3, &exception_table_); |
| 184 | b &= ReadDataDirectory(5, &base_relocation_table_); |
| 185 | b &= ReadDataDirectory(11, &bound_import_table_); |
| 186 | b &= ReadDataDirectory(12, &import_address_table_); |
| 187 | b &= ReadDataDirectory(13, &delay_import_descriptor_); |
| 188 | b &= ReadDataDirectory(14, &clr_runtime_header_); |
Samuel Huang | a34dce5 | 2019-04-03 15:53:13 | [diff] [blame] | 189 | if (!b) |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 190 | return Bad("Malformed data directory"); |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 191 | |
| 192 | // Sections follow the optional header. |
Samuel Huang | a34dce5 | 2019-04-03 15:53:13 | [diff] [blame] | 193 | FileOffset sections_offset = |
| 194 | optional_header_offset + size_of_optional_header_; |
| 195 | if (!IsArrayInBounds(sections_offset, number_of_sections_, sizeof(Section))) |
| 196 | return Bad("Sections past end of file"); |
| 197 | sections_ = reinterpret_cast<const Section*>(start() + sections_offset); |
| 198 | if (!CheckSectionRanges()) |
| 199 | return Bad("Out of bound section"); |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 200 | |
Samuel Huang | a34dce5 | 2019-04-03 15:53:13 | [diff] [blame] | 201 | size_t detected_length = 0; |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 202 | for (int i = 0; i < number_of_sections_; ++i) { |
| 203 | const Section* section = §ions_[i]; |
| 204 | |
| 205 | // TODO(sra): consider using the 'characteristics' field of the section |
| 206 | // header to see if the section contains instructions. |
| 207 | if (memcmp(section->name, ".text", 6) == 0) |
| 208 | has_text_section_ = true; |
| 209 | |
| 210 | uint32_t section_end = |
| 211 | section->file_offset_of_raw_data + section->size_of_raw_data; |
| 212 | if (section_end > detected_length) |
| 213 | detected_length = section_end; |
| 214 | } |
| 215 | |
| 216 | // Pretend our in-memory copy is only as long as our detected length. |
| 217 | ReduceLength(detected_length); |
| 218 | |
| 219 | if (!has_text_section()) { |
| 220 | return Bad("Resource-only executables are not yet supported"); |
| 221 | } |
| 222 | |
| 223 | return Good(); |
| 224 | } |
| 225 | |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 226 | //////////////////////////////////////////////////////////////////////////////// |
| 227 | |
| 228 | bool DisassemblerWin32::ParseRelocs(std::vector<RVA>* relocs) { |
| 229 | relocs->clear(); |
| 230 | |
| 231 | size_t relocs_size = base_relocation_table_.size_; |
| 232 | if (relocs_size == 0) |
| 233 | return true; |
| 234 | |
| 235 | // The format of the base relocation table is a sequence of variable sized |
| 236 | // IMAGE_BASE_RELOCATION blocks. Search for |
| 237 | // "The format of the base relocation data is somewhat quirky" |
| 238 | // at http://msdn.microsoft.com/en-us/library/ms809762.aspx |
| 239 | |
| 240 | const uint8_t* relocs_start = RVAToPointer(base_relocation_table_.address_); |
Etienne Pierre-doray | e058629 | 2019-12-10 23:05:25 | [diff] [blame] | 241 | if (relocs_start == nullptr || relocs_start < start() || |
| 242 | relocs_start >= end()) |
| 243 | return Bad(".relocs outside image"); |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 244 | |
| 245 | // Make sure entire base relocation table is within the buffer. |
Etienne Pierre-doray | e058629 | 2019-12-10 23:05:25 | [diff] [blame] | 246 | if (relocs_size > static_cast<size_t>(end() - relocs_start)) |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 247 | return Bad(".relocs outside image"); |
Etienne Pierre-doray | e058629 | 2019-12-10 23:05:25 | [diff] [blame] | 248 | const uint8_t* relocs_end = relocs_start + relocs_size; |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 249 | |
| 250 | const uint8_t* block = relocs_start; |
| 251 | |
| 252 | // Walk the variable sized blocks. |
| 253 | while (block + 8 < relocs_end) { |
| 254 | RVA page_rva = ReadU32(block, 0); |
| 255 | uint32_t size = ReadU32(block, 4); |
| 256 | if (size < 8 || // Size includes header ... |
| 257 | size % 4 != 0) // ... and is word aligned. |
| 258 | return Bad("Unreasonable relocs block"); |
| 259 | |
| 260 | const uint8_t* end_entries = block + size; |
| 261 | |
| 262 | if (end_entries <= block || end_entries <= start() || end_entries > end()) |
| 263 | return Bad(".relocs block outside image"); |
| 264 | |
| 265 | // Walk through the two-byte entries. |
| 266 | for (const uint8_t* p = block + 8; p < end_entries; p += 2) { |
| 267 | uint16_t entry = ReadU16(p, 0); |
| 268 | int type = entry >> 12; |
| 269 | int offset = entry & 0xFFF; |
| 270 | |
| 271 | RVA rva = page_rva + offset; |
| 272 | // Skip the relocs that live outside of the image. It might be the case |
| 273 | // if a reloc is relative to a register, e.g.: |
| 274 | // mov ecx,dword ptr [eax+044D5888h] |
| 275 | RVA target_rva = PointerToTargetRVA(RVAToPointer(rva)); |
| 276 | if (target_rva == kNoRVA) { |
| 277 | continue; |
| 278 | } |
| 279 | |
| 280 | if (SupportsRelTableType(type)) { |
| 281 | relocs->push_back(rva); |
| 282 | } else if (type == 0) { // IMAGE_REL_BASED_ABSOLUTE |
| 283 | // Ignore, used as padding. |
| 284 | } else { |
| 285 | // Does not occur in Windows x86/x64 executables. |
| 286 | return Bad("Unknown type of reloc"); |
| 287 | } |
| 288 | } |
| 289 | |
| 290 | block += size; |
| 291 | } |
| 292 | |
| 293 | std::sort(relocs->begin(), relocs->end()); |
| 294 | DCHECK(relocs->empty() || relocs->back() != kUnassignedRVA); |
| 295 | |
| 296 | return true; |
| 297 | } |
| 298 | |
| 299 | const Section* DisassemblerWin32::RVAToSection(RVA rva) const { |
| 300 | for (int i = 0; i < number_of_sections_; ++i) { |
| 301 | const Section* section = §ions_[i]; |
| 302 | if (rva >= section->virtual_address) { |
| 303 | FileOffset offset_in_section = rva - section->virtual_address; |
| 304 | if (offset_in_section < section->virtual_size) |
| 305 | return section; |
| 306 | } |
| 307 | } |
| 308 | return nullptr; |
| 309 | } |
| 310 | |
| 311 | std::string DisassemblerWin32::SectionName(const Section* section) { |
| 312 | if (section == nullptr) |
| 313 | return "<none>"; |
| 314 | char name[9]; |
| 315 | memcpy(name, section->name, 8); |
| 316 | name[8] = '\0'; // Ensure termination. |
| 317 | return name; |
| 318 | } |
| 319 | |
etiennep | 5059bca | 2016-07-08 17:55:20 | [diff] [blame] | 320 | // static |
| 321 | bool DisassemblerWin32::QuickDetect(const uint8_t* start, |
| 322 | size_t length, |
| 323 | uint16_t magic) { |
Samuel Huang | a34dce5 | 2019-04-03 15:53:13 | [diff] [blame] | 324 | if (length < kOffsetOfFileAddressOfNewExeHeader + 4) |
etiennep | 5059bca | 2016-07-08 17:55:20 | [diff] [blame] | 325 | return false; |
| 326 | |
| 327 | // Have 'MZ' magic for a DOS header? |
| 328 | if (start[0] != 'M' || start[1] != 'Z') |
| 329 | return false; |
| 330 | |
Samuel Huang | a34dce5 | 2019-04-03 15:53:13 | [diff] [blame] | 331 | FileOffset pe_header_offset = static_cast<FileOffset>( |
etiennep | 5059bca | 2016-07-08 17:55:20 | [diff] [blame] | 332 | ReadU32(start, kOffsetOfFileAddressOfNewExeHeader)); |
Samuel Huang | a34dce5 | 2019-04-03 15:53:13 | [diff] [blame] | 333 | if (pe_header_offset % 8 != 0 || |
| 334 | pe_header_offset < kOffsetOfFileAddressOfNewExeHeader + 4 || |
| 335 | pe_header_offset >= length || |
| 336 | length - pe_header_offset < kMinPeHeaderSize) { |
etiennep | 5059bca | 2016-07-08 17:55:20 | [diff] [blame] | 337 | return false; |
Samuel Huang | a34dce5 | 2019-04-03 15:53:13 | [diff] [blame] | 338 | } |
| 339 | const uint8_t* pe_header = start + pe_header_offset; |
| 340 | if (!(pe_header[0] == 'P' && pe_header[1] == 'E' && pe_header[2] == 0 && |
| 341 | pe_header[3] == 0)) { |
etiennep | 5059bca | 2016-07-08 17:55:20 | [diff] [blame] | 342 | return false; |
Samuel Huang | a34dce5 | 2019-04-03 15:53:13 | [diff] [blame] | 343 | } |
etiennep | 5059bca | 2016-07-08 17:55:20 | [diff] [blame] | 344 | |
Samuel Huang | a34dce5 | 2019-04-03 15:53:13 | [diff] [blame] | 345 | FileOffset optional_header_offset = pe_header_offset + kMinPeHeaderSize; |
| 346 | if (optional_header_offset >= length || length - optional_header_offset < 2) |
etiennep | 5059bca | 2016-07-08 17:55:20 | [diff] [blame] | 347 | return false; |
Samuel Huang | a34dce5 | 2019-04-03 15:53:13 | [diff] [blame] | 348 | const uint8_t* optional_header = start + optional_header_offset; |
| 349 | return magic == ReadU16(optional_header, 0); |
| 350 | } |
etiennep | 5059bca | 2016-07-08 17:55:20 | [diff] [blame] | 351 | |
Samuel Huang | a34dce5 | 2019-04-03 15:53:13 | [diff] [blame] | 352 | bool DisassemblerWin32::IsRvaRangeInBounds(size_t start, size_t length) { |
| 353 | return start < size_of_image_ && length <= size_of_image_ - start; |
| 354 | } |
| 355 | |
| 356 | bool DisassemblerWin32::CheckSectionRanges() { |
| 357 | for (int i = 0; i < number_of_sections_; ++i) { |
| 358 | const Section* section = §ions_[i]; |
| 359 | if (!IsRangeInBounds(section->file_offset_of_raw_data, |
| 360 | section->size_of_raw_data) || |
| 361 | !IsRvaRangeInBounds(section->virtual_address, section->virtual_size)) { |
| 362 | return false; |
| 363 | } |
| 364 | } |
etiennep | 5059bca | 2016-07-08 17:55:20 | [diff] [blame] | 365 | return true; |
| 366 | } |
| 367 | |
huangs | 257f9fb | 2017-03-23 23:17:50 | [diff] [blame] | 368 | bool DisassemblerWin32::ExtractAbs32Locations() { |
huangs | dc779d9 | 2017-03-01 22:22:38 | [diff] [blame] | 369 | abs32_locations_.clear(); |
| 370 | if (!ParseRelocs(&abs32_locations_)) |
| 371 | return false; |
| 372 | |
| 373 | #if COURGETTE_HISTOGRAM_TARGETS |
| 374 | for (size_t i = 0; i < abs32_locations_.size(); ++i) { |
| 375 | RVA rva = abs32_locations_[i]; |
| 376 | // The 4 bytes at the relocation are a reference to some address. |
| 377 | ++abs32_target_rvas_[PointerToTargetRVA(RVAToPointer(rva))]; |
| 378 | } |
| 379 | #endif |
| 380 | return true; |
| 381 | } |
| 382 | |
huangs | 257f9fb | 2017-03-23 23:17:50 | [diff] [blame] | 383 | bool DisassemblerWin32::ExtractRel32Locations() { |
huangs | dc779d9 | 2017-03-01 22:22:38 | [diff] [blame] | 384 | FileOffset file_offset = 0; |
| 385 | while (file_offset < length()) { |
| 386 | const Section* section = FindNextSection(file_offset); |
| 387 | if (section == nullptr) |
| 388 | break; |
| 389 | if (file_offset < section->file_offset_of_raw_data) |
| 390 | file_offset = section->file_offset_of_raw_data; |
| 391 | ParseRel32RelocsFromSection(section); |
| 392 | file_offset += section->size_of_raw_data; |
| 393 | } |
| 394 | std::sort(rel32_locations_.begin(), rel32_locations_.end()); |
| 395 | DCHECK(rel32_locations_.empty() || rel32_locations_.back() != kUnassignedRVA); |
| 396 | |
| 397 | #if COURGETTE_HISTOGRAM_TARGETS |
| 398 | VLOG(1) << "abs32_locations_ " << abs32_locations_.size() |
| 399 | << "\nrel32_locations_ " << rel32_locations_.size() |
| 400 | << "\nabs32_target_rvas_ " << abs32_target_rvas_.size() |
| 401 | << "\nrel32_target_rvas_ " << rel32_target_rvas_.size(); |
| 402 | |
| 403 | int common = 0; |
| 404 | std::map<RVA, int>::iterator abs32_iter = abs32_target_rvas_.begin(); |
| 405 | std::map<RVA, int>::iterator rel32_iter = rel32_target_rvas_.begin(); |
| 406 | while (abs32_iter != abs32_target_rvas_.end() && |
| 407 | rel32_iter != rel32_target_rvas_.end()) { |
| 408 | if (abs32_iter->first < rel32_iter->first) { |
| 409 | ++abs32_iter; |
| 410 | } else if (rel32_iter->first < abs32_iter->first) { |
| 411 | ++rel32_iter; |
| 412 | } else { |
| 413 | ++common; |
| 414 | ++abs32_iter; |
| 415 | ++rel32_iter; |
| 416 | } |
| 417 | } |
| 418 | VLOG(1) << "common " << common; |
| 419 | #endif |
huangs | 257f9fb | 2017-03-23 23:17:50 | [diff] [blame] | 420 | return true; |
huangs | dc779d9 | 2017-03-01 22:22:38 | [diff] [blame] | 421 | } |
| 422 | |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 423 | RvaVisitor* DisassemblerWin32::CreateAbs32TargetRvaVisitor() { |
| 424 | return new RvaVisitor_Abs32(abs32_locations_, *this); |
| 425 | } |
| 426 | |
| 427 | RvaVisitor* DisassemblerWin32::CreateRel32TargetRvaVisitor() { |
| 428 | return new RvaVisitor_Rel32(rel32_locations_, *this); |
| 429 | } |
| 430 | |
| 431 | void DisassemblerWin32::RemoveUnusedRel32Locations( |
| 432 | AssemblyProgram* program) { |
| 433 | auto cond = [this, program](RVA rva) -> bool { |
| 434 | // + 4 since offset is relative to start of next instruction. |
| 435 | RVA target_rva = rva + 4 + Read32LittleEndian(RVAToPointer(rva)); |
| 436 | return program->FindRel32Label(target_rva) == nullptr; |
| 437 | }; |
| 438 | rel32_locations_.erase( |
| 439 | std::remove_if(rel32_locations_.begin(), rel32_locations_.end(), cond), |
| 440 | rel32_locations_.end()); |
| 441 | } |
| 442 | |
huangs | 257f9fb | 2017-03-23 23:17:50 | [diff] [blame] | 443 | InstructionGenerator DisassemblerWin32::GetInstructionGenerator( |
| 444 | AssemblyProgram* program) { |
tzik | 0881a400 | 2018-03-08 06:19:49 | [diff] [blame] | 445 | return base::BindRepeating(&DisassemblerWin32::ParseFile, |
| 446 | base::Unretained(this), program); |
huangs | 257f9fb | 2017-03-23 23:17:50 | [diff] [blame] | 447 | } |
| 448 | |
huangs | 7b221a5 | 2016-11-09 22:28:23 | [diff] [blame] | 449 | CheckBool DisassemblerWin32::ParseFile(AssemblyProgram* program, |
| 450 | InstructionReceptor* receptor) const { |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 451 | // Walk all the bytes in the file, whether or not in a section. |
| 452 | FileOffset file_offset = 0; |
| 453 | while (file_offset < length()) { |
| 454 | const Section* section = FindNextSection(file_offset); |
| 455 | if (section == nullptr) { |
| 456 | // No more sections. There should not be extra stuff following last |
| 457 | // section. |
huangs | 7b221a5 | 2016-11-09 22:28:23 | [diff] [blame] | 458 | // ParseNonSectionFileRegion(file_offset, pe_info().length(), receptor); |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 459 | break; |
| 460 | } |
| 461 | if (file_offset < section->file_offset_of_raw_data) { |
| 462 | FileOffset section_start_offset = section->file_offset_of_raw_data; |
| 463 | if (!ParseNonSectionFileRegion(file_offset, section_start_offset, |
huangs | 7b221a5 | 2016-11-09 22:28:23 | [diff] [blame] | 464 | receptor)) { |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 465 | return false; |
| 466 | } |
| 467 | |
| 468 | file_offset = section_start_offset; |
| 469 | } |
| 470 | FileOffset end = file_offset + section->size_of_raw_data; |
huangs | 7b221a5 | 2016-11-09 22:28:23 | [diff] [blame] | 471 | if (!ParseFileRegion(section, file_offset, end, program, receptor)) |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 472 | return false; |
| 473 | file_offset = end; |
| 474 | } |
| 475 | |
| 476 | #if COURGETTE_HISTOGRAM_TARGETS |
| 477 | HistogramTargets("abs32 relocs", abs32_target_rvas_); |
| 478 | HistogramTargets("rel32 relocs", rel32_target_rvas_); |
| 479 | #endif |
| 480 | |
| 481 | return true; |
| 482 | } |
| 483 | |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 484 | CheckBool DisassemblerWin32::ParseNonSectionFileRegion( |
| 485 | FileOffset start_file_offset, |
| 486 | FileOffset end_file_offset, |
huangs | 7b221a5 | 2016-11-09 22:28:23 | [diff] [blame] | 487 | InstructionReceptor* receptor) const { |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 488 | if (incomplete_disassembly_) |
| 489 | return true; |
| 490 | |
| 491 | if (end_file_offset > start_file_offset) { |
huangs | 7b221a5 | 2016-11-09 22:28:23 | [diff] [blame] | 492 | if (!receptor->EmitMultipleBytes(FileOffsetToPointer(start_file_offset), |
| 493 | end_file_offset - start_file_offset)) { |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 494 | return false; |
| 495 | } |
| 496 | } |
| 497 | |
| 498 | return true; |
| 499 | } |
| 500 | |
huangs | 7b221a5 | 2016-11-09 22:28:23 | [diff] [blame] | 501 | CheckBool DisassemblerWin32::ParseFileRegion( |
| 502 | const Section* section, |
| 503 | FileOffset start_file_offset, |
| 504 | FileOffset end_file_offset, |
| 505 | AssemblyProgram* program, |
| 506 | InstructionReceptor* receptor) const { |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 507 | RVA relocs_start_rva = base_relocation_table().address_; |
| 508 | |
| 509 | const uint8_t* start_pointer = FileOffsetToPointer(start_file_offset); |
| 510 | const uint8_t* end_pointer = FileOffsetToPointer(end_file_offset); |
| 511 | |
| 512 | RVA start_rva = FileOffsetToRVA(start_file_offset); |
| 513 | RVA end_rva = start_rva + section->virtual_size; |
| 514 | const int kVAWidth = AbsVAWidth(); |
| 515 | |
| 516 | // Quick way to convert from Pointer to RVA within a single Section is to |
| 517 | // subtract 'pointer_to_rva'. |
| 518 | const uint8_t* const adjust_pointer_to_rva = start_pointer - start_rva; |
| 519 | |
huangs | 7b221a5 | 2016-11-09 22:28:23 | [diff] [blame] | 520 | std::vector<RVA>::const_iterator rel32_pos = rel32_locations_.begin(); |
| 521 | std::vector<RVA>::const_iterator abs32_pos = abs32_locations_.begin(); |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 522 | |
huangs | 7b221a5 | 2016-11-09 22:28:23 | [diff] [blame] | 523 | if (!receptor->EmitOrigin(start_rva)) |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 524 | return false; |
| 525 | |
| 526 | const uint8_t* p = start_pointer; |
| 527 | |
| 528 | while (p < end_pointer) { |
| 529 | RVA current_rva = static_cast<RVA>(p - adjust_pointer_to_rva); |
| 530 | |
| 531 | // The base relocation table is usually in the .relocs section, but it could |
| 532 | // actually be anywhere. Make sure we skip it because we will regenerate it |
| 533 | // during assembly. |
| 534 | if (current_rva == relocs_start_rva) { |
huangs | 7b221a5 | 2016-11-09 22:28:23 | [diff] [blame] | 535 | if (!receptor->EmitPeRelocs()) |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 536 | return false; |
| 537 | uint32_t relocs_size = base_relocation_table().size_; |
| 538 | if (relocs_size) { |
| 539 | p += relocs_size; |
| 540 | continue; |
| 541 | } |
| 542 | } |
| 543 | |
| 544 | while (abs32_pos != abs32_locations_.end() && *abs32_pos < current_rva) |
| 545 | ++abs32_pos; |
| 546 | |
| 547 | if (abs32_pos != abs32_locations_.end() && *abs32_pos == current_rva) { |
| 548 | RVA target_rva = PointerToTargetRVA(p); |
| 549 | DCHECK_NE(kNoRVA, target_rva); |
| 550 | // TODO(sra): target could be Label+offset. It is not clear how to guess |
| 551 | // which it might be. We assume offset==0. |
| 552 | Label* label = program->FindAbs32Label(target_rva); |
| 553 | DCHECK(label); |
huangs | 7b221a5 | 2016-11-09 22:28:23 | [diff] [blame] | 554 | if (!EmitAbs(label, receptor)) |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 555 | return false; |
| 556 | p += kVAWidth; |
| 557 | continue; |
| 558 | } |
| 559 | |
| 560 | while (rel32_pos != rel32_locations_.end() && *rel32_pos < current_rva) |
| 561 | ++rel32_pos; |
| 562 | |
| 563 | if (rel32_pos != rel32_locations_.end() && *rel32_pos == current_rva) { |
| 564 | // + 4 since offset is relative to start of next instruction. |
| 565 | RVA target_rva = current_rva + 4 + Read32LittleEndian(p); |
| 566 | Label* label = program->FindRel32Label(target_rva); |
| 567 | DCHECK(label); |
huangs | 7b221a5 | 2016-11-09 22:28:23 | [diff] [blame] | 568 | if (!receptor->EmitRel32(label)) |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 569 | return false; |
| 570 | p += 4; |
| 571 | continue; |
| 572 | } |
| 573 | |
| 574 | if (incomplete_disassembly_) { |
| 575 | if ((abs32_pos == abs32_locations_.end() || end_rva <= *abs32_pos) && |
| 576 | (rel32_pos == rel32_locations_.end() || end_rva <= *rel32_pos) && |
| 577 | (end_rva <= relocs_start_rva || current_rva >= relocs_start_rva)) { |
| 578 | // No more relocs in this section, don't bother encoding bytes. |
| 579 | break; |
| 580 | } |
| 581 | } |
| 582 | |
huangs | 7b221a5 | 2016-11-09 22:28:23 | [diff] [blame] | 583 | if (!receptor->EmitSingleByte(*p)) |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 584 | return false; |
| 585 | p += 1; |
| 586 | } |
| 587 | |
| 588 | return true; |
| 589 | } |
| 590 | |
| 591 | #if COURGETTE_HISTOGRAM_TARGETS |
| 592 | // Histogram is printed to std::cout. It is purely for debugging the algorithm |
| 593 | // and is only enabled manually in 'exploration' builds. I don't want to add |
| 594 | // command-line configuration for this feature because this code has to be |
| 595 | // small, which means compiled-out. |
| 596 | void DisassemblerWin32::HistogramTargets(const char* kind, |
huangs | 7b221a5 | 2016-11-09 22:28:23 | [diff] [blame] | 597 | const std::map<RVA, int>& map) const { |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 598 | int total = 0; |
| 599 | std::map<int, std::vector<RVA>> h; |
| 600 | for (std::map<RVA, int>::const_iterator p = map.begin(); p != map.end(); |
| 601 | ++p) { |
| 602 | h[p->second].push_back(p->first); |
| 603 | total += p->second; |
| 604 | } |
| 605 | |
| 606 | std::cout << total << " " << kind << " to " << map.size() << " unique targets" |
| 607 | << std::endl; |
| 608 | |
| 609 | std::cout << "indegree: #targets-with-indegree (example)" << std::endl; |
| 610 | const int kFirstN = 15; |
| 611 | bool someSkipped = false; |
| 612 | int index = 0; |
| 613 | for (std::map<int, std::vector<RVA>>::reverse_iterator p = h.rbegin(); |
| 614 | p != h.rend(); ++p) { |
| 615 | ++index; |
| 616 | if (index <= kFirstN || p->first <= 3) { |
| 617 | if (someSkipped) { |
| 618 | std::cout << "..." << std::endl; |
| 619 | } |
| 620 | size_t count = p->second.size(); |
| 621 | std::cout << std::dec << p->first << ": " << count; |
| 622 | if (count <= 2) { |
| 623 | for (size_t i = 0; i < count; ++i) |
| 624 | std::cout << " " << DescribeRVA(p->second[i]); |
| 625 | } |
| 626 | std::cout << std::endl; |
| 627 | someSkipped = false; |
| 628 | } else { |
| 629 | someSkipped = true; |
| 630 | } |
| 631 | } |
| 632 | } |
| 633 | #endif // COURGETTE_HISTOGRAM_TARGETS |
| 634 | |
| 635 | // DescribeRVA is for debugging only. I would put it under #ifdef DEBUG except |
| 636 | // that during development I'm finding I need to call it when compiled in |
| 637 | // Release mode. Hence: |
| 638 | // TODO(sra): make this compile only for debug mode. |
| 639 | std::string DisassemblerWin32::DescribeRVA(RVA rva) const { |
| 640 | const Section* section = RVAToSection(rva); |
| 641 | std::ostringstream s; |
| 642 | s << std::hex << rva; |
| 643 | if (section) { |
| 644 | s << " ("; |
| 645 | s << SectionName(section) << "+" << std::hex |
| 646 | << (rva - section->virtual_address) << ")"; |
| 647 | } |
| 648 | return s.str(); |
| 649 | } |
| 650 | |
| 651 | const Section* DisassemblerWin32::FindNextSection( |
| 652 | FileOffset file_offset) const { |
Raul Tambre | 5bd9298 | 2019-03-28 06:21:55 | [diff] [blame] | 653 | const Section* best = nullptr; |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 654 | for (int i = 0; i < number_of_sections_; ++i) { |
| 655 | const Section* section = §ions_[i]; |
| 656 | if (section->size_of_raw_data > 0) { // i.e. has data in file. |
| 657 | if (file_offset <= section->file_offset_of_raw_data) { |
Raul Tambre | 5bd9298 | 2019-03-28 06:21:55 | [diff] [blame] | 658 | if (best == nullptr || |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 659 | section->file_offset_of_raw_data < best->file_offset_of_raw_data) { |
| 660 | best = section; |
| 661 | } |
| 662 | } |
| 663 | } |
| 664 | } |
| 665 | return best; |
| 666 | } |
| 667 | |
| 668 | bool DisassemblerWin32::ReadDataDirectory(int index, |
| 669 | ImageDataDirectory* directory) { |
| 670 | if (index < number_of_data_directories_) { |
Samuel Huang | a34dce5 | 2019-04-03 15:53:13 | [diff] [blame] | 671 | FileOffset file_offset = index * 8 + RelativeOffsetOfDataDirectories(); |
etiennep | 5ac34c9 | 2016-05-20 15:44:46 | [diff] [blame] | 672 | if (file_offset >= size_of_optional_header_) |
| 673 | return Bad("Number of data directories inconsistent"); |
| 674 | const uint8_t* data_directory = optional_header_ + file_offset; |
| 675 | if (data_directory < start() || data_directory + 8 >= end()) |
| 676 | return Bad("Data directory outside image"); |
| 677 | RVA rva = ReadU32(data_directory, 0); |
| 678 | size_t size = ReadU32(data_directory, 4); |
| 679 | if (size > size_of_image_) |
| 680 | return Bad("Data directory size too big"); |
| 681 | |
| 682 | // TODO(sra): validate RVA. |
| 683 | directory->address_ = rva; |
| 684 | directory->size_ = static_cast<uint32_t>(size); |
| 685 | return true; |
| 686 | } else { |
| 687 | directory->address_ = 0; |
| 688 | directory->size_ = 0; |
| 689 | return true; |
| 690 | } |
| 691 | } |
| 692 | |
| 693 | } // namespace courgette |