324 lines
11 KiB
C++
324 lines
11 KiB
C++
#include <windows.h>
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#include <coffi/coffi.hpp>
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#include <CLI11.hpp>
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#include <spdlog/spdlog.h>
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int main(int argc, char *argv[]) {
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CLI::App app("Patcher");
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std::string inputFile;
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std::string outputFile;
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app.add_option("-i,--input", inputFile, "Input exe file to patch")
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->required();
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app.add_option("-o,--output", outputFile, "Output patched exe file")
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->required();
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CLI11_PARSE(app, argc, argv);
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// Load the object file containing the main function
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COFFI::coffi objReader;
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std::string objPath = SRC_OBJECT;
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SPDLOG_INFO("Loading object file: {}", objPath);
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if (!objReader.load(objPath)) {
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spdlog::error("Failed to load object file: {}", objPath);
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return 1;
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}
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// Load the source PE file
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COFFI::coffi peReader;
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SPDLOG_INFO("Loading PE file: {}", inputFile);
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if (!peReader.load(inputFile)) {
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spdlog::error("Failed to load PE file: {}", inputFile);
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return 1;
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}
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// Find the 'main' function in the object file
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auto &symbols = *objReader.get_symbols();
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COFFI::symbol *mainSymbol = nullptr;
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for (auto &sym : symbols) {
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SPDLOG_INFO("Symbol: {}", sym.get_name());
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if (sym.get_name() == "_ref") {
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mainSymbol = &sym;
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break;
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}
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}
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if (!mainSymbol) {
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spdlog::error("Could not find 'main' symbol in object file");
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return 1;
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}
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// Get the section containing the main function
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auto §ions = objReader.get_sections();
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auto mainSection = sections[mainSymbol->get_section_number() - 1];
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// Calculate main function size using next symbol method
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uint32_t mainOffset = mainSymbol->get_value();
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uint32_t mainSize = 0;
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// Find the next symbol in the same section to calculate size
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uint32_t nextSymbolOffset = UINT32_MAX;
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for (auto &sym : symbols) {
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if (sym.get_section_number() == mainSymbol->get_section_number() &&
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sym.get_value() > mainOffset && sym.get_value() < nextSymbolOffset) {
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nextSymbolOffset = sym.get_value();
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}
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}
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if (nextSymbolOffset != UINT32_MAX) {
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mainSize = nextSymbolOffset - mainOffset;
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spdlog::info(
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"Calculated main function size: {} bytes (next symbol at offset {})",
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mainSize, nextSymbolOffset);
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} else {
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// If no next symbol found, use remaining section size
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mainSize = mainSection->get_data_size() - mainOffset;
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spdlog::info("No next symbol found, using remaining section size: {} bytes",
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mainSize);
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}
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auto mainCodeData = mainSection->get_data();
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spdlog::info("Found main function at offset {} with size {}", mainOffset,
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mainSize);
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// List relocations for the main function section
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auto& sectionRelocations = mainSection->get_relocations();
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spdlog::info("Relocations for section {} (containing main function):", mainSymbol->get_section_number());
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for (auto& reloc : sectionRelocations) {
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spdlog::info(" Relocation at offset 0x{:x}, type: {}, symbol index: {}",
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reloc.get_virtual_address(),
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reloc.get_type(),
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reloc.get_symbol_table_index());
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// Get symbol name for this relocation
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spdlog::info(" -> Symbol: {}", reloc.get_symbol());
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}
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spdlog::info("Main function code:");
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std::string s;
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for (uint32_t i = 0; i < mainSize; i++) {
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if (i > 0 && i % 16 == 0) {
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spdlog::info("{}", s);
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s.clear();
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}
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if (s.size() > 0)
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s += " ";
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s += fmt::format("{:02X}", mainCodeData[i]);
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}
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if (s.size() > 0)
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spdlog::info("{}", s);
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// Find .text section in PE file
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auto &peSections = peReader.get_sections();
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COFFI::section *textSection = nullptr;
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for (auto §ion : peSections) {
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if (section->get_name() == ".text") {
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textSection = section;
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break;
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}
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}
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if (!textSection) {
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spdlog::error("Could not find .text section in PE file");
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return 1;
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}
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// Get image base and calculate actual VA
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uint64_t imageBase = 0;
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auto winHeader = peReader.get_win_header();
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if (winHeader) {
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imageBase = winHeader->get_image_base();
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}
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uint32_t textSectionRVA = textSection->get_virtual_address();
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uint32_t textSectionSize = textSection->get_virtual_size();
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uint64_t textSectionVA = imageBase + textSectionRVA;
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uint64_t textSectionEndVA = textSectionVA + textSectionSize;
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spdlog::info("PE Image base: 0x{:x}", imageBase);
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spdlog::info(".text section RVA: 0x{:x}, size: 0x{:x}", textSectionRVA, textSectionSize);
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spdlog::info(".text section VA: 0x{:x} - 0x{:x}", textSectionVA, textSectionEndVA);
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// Find available space at the end of .text section (look for null bytes)
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auto textSectionData = textSection->get_data();
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uint32_t originalTextSize = textSection->get_data_size();
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// Search backwards from the end to find contiguous null bytes
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uint32_t availableSpace = 0;
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for (int32_t i = originalTextSize - 1; i >= 0; i--) {
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if (reinterpret_cast<const uint8_t*>(textSectionData)[i] == 0x00) {
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availableSpace++;
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} else {
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break; // Found non-null byte, stop counting
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}
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}
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spdlog::info("Found {} bytes of available space (null bytes) at end of .text section", availableSpace);
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if (availableSpace < mainSize) {
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spdlog::error("Not enough space in .text section! Need {} bytes, found {} bytes",
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mainSize, availableSpace);
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return 1;
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}
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// Calculate injection offset (place code at start of null space)
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uint32_t injectionOffset = originalTextSize - availableSpace;
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uint64_t injectionVA = textSectionVA + injectionOffset;
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spdlog::info("Injecting {} bytes at .text section offset 0x{:x} (VA: 0x{:x})",
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mainSize, injectionOffset, injectionVA);
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// Copy the main function code into the available space
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const uint8_t* mainCode = reinterpret_cast<const uint8_t*>(mainCodeData) + mainOffset;
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// Create a copy of the section data to modify
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std::vector<uint8_t> newTextData(reinterpret_cast<const uint8_t*>(textSectionData),
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reinterpret_cast<const uint8_t*>(textSectionData) + originalTextSize);
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// Copy our code into the null space
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std::memcpy(newTextData.data() + injectionOffset, mainCode, mainSize);
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// Now handle relocations - resolve imports and copy constants to .rdata
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spdlog::info("Processing relocations...");
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// Find .rdata section for constants
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COFFI::section* rdataSection = nullptr;
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for (auto& section : peSections) {
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if (section->get_name() == ".rdata") {
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rdataSection = section;
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break;
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}
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}
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if (!rdataSection) {
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spdlog::error("Could not find .rdata section in PE file");
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return 1;
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}
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// Find available space in .rdata section (similar to .text)
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auto rdataData = rdataSection->get_data();
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uint32_t rdataSize = rdataSection->get_data_size();
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uint32_t rdataAvailableSpace = 0;
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for (int32_t i = rdataSize - 1; i >= 0; i--) {
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if (reinterpret_cast<const uint8_t*>(rdataData)[i] == 0x00) {
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rdataAvailableSpace++;
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} else {
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break;
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}
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}
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spdlog::info("Found {} bytes of available space in .rdata section", rdataAvailableSpace);
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// Create rdata copy for modifications
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std::vector<uint8_t> newRdataData(reinterpret_cast<const uint8_t*>(rdataData),
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reinterpret_cast<const uint8_t*>(rdataData) + rdataSize);
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uint32_t rdataInjectionOffset = rdataSize - rdataAvailableSpace;
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uint32_t rdataCurrentOffset = rdataInjectionOffset;
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// Get import table information for resolving __imp_ symbols
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auto& directories = peReader.get_directories();
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uint32_t importRVA = 0;
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if (directories.size() > 1) {
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importRVA = directories[1]->get_virtual_address(); // Import table is directory entry 1
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}
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// Process each relocation
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for (auto& reloc : sectionRelocations) {
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if (reloc.get_type() != 6) continue; // Only handle type 6 (IMAGE_REL_I386_DIR32)
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uint32_t relocOffset = reloc.get_virtual_address();
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std::string symbolName = reloc.get_symbol();
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uint32_t resolvedAddress = 0;
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spdlog::info("Processing relocation at offset 0x{:x} for symbol: {}", relocOffset, symbolName);
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if (symbolName.starts_with("__imp_")) {
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// This is an import symbol - find it in the PE's import table
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std::string functionName = symbolName.substr(6); // Remove "__imp_" prefix
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// Remove @N suffix for stdcall functions
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size_t atPos = functionName.find('@');
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if (atPos != std::string::npos) {
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functionName = functionName.substr(0, atPos);
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}
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spdlog::info("Looking for import function: {}", functionName);
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// For now, we'll need to implement import table parsing
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// This is a placeholder - you'd need to parse the import table to find the actual IAT address
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spdlog::warn("Import resolution not fully implemented yet for: {}", functionName);
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resolvedAddress = 0x12345678; // Placeholder
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} else if (symbolName.starts_with("??_C@")) {
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// This is a string constant - find it in the object file and copy to .rdata
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COFFI::symbol* constSymbol = nullptr;
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for (auto& sym : symbols) {
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if (sym.get_name() == symbolName) {
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constSymbol = &sym;
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break;
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}
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}
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if (constSymbol) {
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// Get the string data from the object file
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auto constSection = sections[constSymbol->get_section_number() - 1];
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auto constData = constSection->get_data();
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uint32_t constOffset = constSymbol->get_value();
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// Find the string length (null-terminated)
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uint32_t stringLen = 0;
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while (constData[constOffset + stringLen] != 0) {
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stringLen++;
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}
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stringLen++; // Include null terminator
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if (rdataCurrentOffset + stringLen > rdataSize) {
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spdlog::error("Not enough space in .rdata for string constant");
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return 1;
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}
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// Copy string to .rdata
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std::memcpy(newRdataData.data() + rdataCurrentOffset,
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constData + constOffset, stringLen);
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// Calculate the new address
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uint32_t rdataRVA = rdataSection->get_virtual_address();
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resolvedAddress = imageBase + rdataRVA + rdataCurrentOffset;
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spdlog::info("Copied string constant '{}' to .rdata at RVA 0x{:x} (VA: 0x{:x})",
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std::string(constData + constOffset),
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rdataRVA + rdataCurrentOffset, resolvedAddress);
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rdataCurrentOffset += stringLen;
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}
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}
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// Apply the relocation to the injected code
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if (resolvedAddress != 0) {
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uint32_t patchOffset = injectionOffset + relocOffset;
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*reinterpret_cast<uint32_t*>(newTextData.data() + patchOffset) = resolvedAddress;
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spdlog::info("Applied relocation: patched offset 0x{:x} with address 0x{:x}",
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patchOffset, resolvedAddress);
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}
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}
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// Update both sections
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rdataSection->set_data(reinterpret_cast<const char*>(newRdataData.data()), newRdataData.size());
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// Update the .text section with modified data (same size)
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textSection->set_data(reinterpret_cast<const char*>(newTextData.data()), newTextData.size());
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spdlog::info("Injected code into existing .text section space (size unchanged: 0x{:x})", originalTextSize);
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// Save the modified PE file to output path
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spdlog::info("Saving patched PE file to: {}", outputFile);
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if (!peReader.save(outputFile)) {
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spdlog::error("Failed to save patched PE file to: {}", outputFile);
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return 1;
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}
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spdlog::info("Successfully patched PE file! Main function injected at VA: 0x{:x}", injectionVA);
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return 0;
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} |