396 lines
12 KiB
C++
396 lines
12 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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struct Patcher {
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COFFI::coffi objReader;
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COFFI::coffi peReader;
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std::string inputFile;
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std::string outputFile;
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COFFI::symbol *mainSymbol = nullptr;
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COFFI::section *mainSection = nullptr;
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COFFI::section *textSection = nullptr;
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COFFI::section *rdataSection = nullptr;
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uint64_t imageBase = 0;
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uint32_t mainOffset = 0;
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uint32_t mainSize = 0;
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bool loadFiles() {
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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 false;
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}
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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 false;
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}
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// Get image base
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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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spdlog::info("PE Image base: 0x{:x}", imageBase);
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return true;
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}
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bool findMainSymbol() {
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auto &symbols = *objReader.get_symbols();
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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 false;
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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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mainSection = sections[mainSymbol->get_section_number() - 1];
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mainOffset = mainSymbol->get_value();
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return true;
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}
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uint32_t calculateMainSize() {
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auto &symbols = *objReader.get_symbols();
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uint32_t nextSymbolOffset = UINT32_MAX;
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// Find the next symbol in the same section to calculate size
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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(
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"No next symbol found, using remaining section size: {} bytes",
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mainSize);
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}
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return mainSize;
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}
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COFFI::section *findSection(const std::string &name, bool isPE = true) {
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auto §ions = isPE ? peReader.get_sections() : objReader.get_sections();
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for (auto §ion : sections) {
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if (section->get_name() == name) {
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return section;
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}
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}
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return nullptr;
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}
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uint32_t findAvailableSpaceAtEnd(COFFI::section *section) {
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auto sectionData = section->get_data();
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uint32_t sectionSize = section->get_data_size();
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const char *sectionEnd = sectionData + sectionSize;
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uint32_t availableSpace = 0;
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// Search backwards from the end to find contiguous null bytes
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const char *ptr = sectionEnd-1;
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while (ptr > sectionData) {
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if (*ptr != 0x00) {
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break;
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}
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availableSpace++;
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ptr--;
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}
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// }
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// for (int32_t i = sectionSize - 1; i >= 0; i--) {
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// if (reinterpret_cast<const uint8_t*>(sectionData)[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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return availableSpace;
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}
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void logMainFunctionCode() {
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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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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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}
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void logRelocations() {
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auto §ionRelocations = mainSection->get_relocations();
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spdlog::info("Relocations for section {} (containing main function):",
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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(), reloc.get_type(),
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reloc.get_symbol_table_index());
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spdlog::info(" -> Symbol: {}", reloc.get_symbol());
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}
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}
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void logSectionData(COFFI::section *section) {
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uint32_t sectionRVA = section->get_virtual_address();
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uint32_t sectionSize = section->get_virtual_size();
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uint64_t sectionVA = imageBase + sectionRVA;
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uint64_t sectionEndVA = sectionVA + sectionSize;
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spdlog::info("Section {} RVA: 0x{:x}, size: 0x{:x}", section->get_name(),
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sectionRVA, sectionSize);
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spdlog::info("Section {} VA: 0x{:x} - 0x{:x}", section->get_name(),
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sectionVA, sectionEndVA);
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}
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bool validateSections() {
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textSection = findSection(".text");
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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 false;
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}
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logSectionData(textSection);
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rdataSection = findSection(".rdata");
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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 false;
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}
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logSectionData(rdataSection);
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return true;
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}
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bool processRelocations(std::vector<uint8_t> &newTextData,
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std::vector<uint8_t> &newRdataData,
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uint32_t injectionOffset,
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uint32_t &rdataCurrentOffset) {
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auto &symbols = *objReader.get_symbols();
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auto §ions = objReader.get_sections();
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auto §ionRelocations = mainSection->get_relocations();
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uint32_t rdataSize = rdataSection->get_data_size();
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uint32_t rdataRVA = rdataSection->get_virtual_address();
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spdlog::info("Processing relocations...");
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for (auto &reloc : sectionRelocations) {
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if (reloc.get_type() != 6)
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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: {}",
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relocOffset, symbolName);
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if (symbolName.starts_with("__imp_")) {
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// Import symbol handling
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std::string functionName = symbolName.substr(6);
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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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spdlog::warn("Import resolution not fully implemented yet for: {}",
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functionName);
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resolvedAddress = 0x12345678; // Placeholder
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} else if (symbolName.starts_with("??_C@")) {
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// String constant handling
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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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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 string length
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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 false;
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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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resolvedAddress = imageBase + rdataRVA + rdataCurrentOffset;
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spdlog::info("Copied string constant '{}' to .rdata at RVA 0x{:x} "
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"(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
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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) =
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resolvedAddress;
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spdlog::info(
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"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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return true;
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}
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bool patchAndSave() {
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// Check available space in both sections
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uint32_t textAvailableSpace = findAvailableSpaceAtEnd(textSection);
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uint32_t rdataAvailableSpace = findAvailableSpaceAtEnd(rdataSection);
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spdlog::info("Found {} bytes of available space (null bytes) at end of "
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".text section",
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textAvailableSpace);
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spdlog::info("Found {} bytes of available space in .rdata section",
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rdataAvailableSpace);
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if (textAvailableSpace < mainSize) {
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spdlog::error(
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"Not enough space in .text section! Need {} bytes, found {} bytes",
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mainSize, textAvailableSpace);
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return false;
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}
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// Calculate injection points
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uint32_t textSize = textSection->get_data_size();
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uint32_t rdataSize = rdataSection->get_data_size();
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uint32_t injectionOffset = textSize - textAvailableSpace;
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uint32_t rdataInjectionOffset = rdataSize - rdataAvailableSpace;
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uint32_t rdataCurrentOffset = rdataInjectionOffset;
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uint64_t textSectionVA = imageBase + textSection->get_virtual_address();
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uint64_t injectionVA = textSectionVA + injectionOffset;
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spdlog::info(
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"Injecting {} bytes at .text section offset 0x{:x} (VA: 0x{:x})",
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mainSize, injectionOffset, injectionVA);
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// Create copies of section data
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auto textSectionData = textSection->get_data();
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auto rdataData = rdataSection->get_data();
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std::vector<uint8_t> newTextData(
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reinterpret_cast<const uint8_t *>(textSectionData),
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reinterpret_cast<const uint8_t *>(textSectionData) + textSize);
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std::vector<uint8_t> newRdataData(
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reinterpret_cast<const uint8_t *>(rdataData),
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reinterpret_cast<const uint8_t *>(rdataData) + rdataSize);
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// Copy main function code
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const uint8_t *mainCode =
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reinterpret_cast<const uint8_t *>(mainSection->get_data()) + mainOffset;
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std::memcpy(newTextData.data() + injectionOffset, mainCode, mainSize);
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// Process relocations
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if (!processRelocations(newTextData, newRdataData, injectionOffset,
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rdataCurrentOffset)) {
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return false;
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}
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// Update sections
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rdataSection->set_data(reinterpret_cast<const char *>(newRdataData.data()),
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newRdataData.size());
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textSection->set_data(reinterpret_cast<const char *>(newTextData.data()),
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newTextData.size());
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spdlog::info("Injected code into existing .text section space (size "
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"unchanged: 0x{:x})",
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textSize);
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// Save the modified PE file
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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 false;
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}
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spdlog::info(
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"Successfully patched PE file! Main function injected at VA: 0x{:x}",
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injectionVA);
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return true;
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}
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bool run() {
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if (!loadFiles())
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return false;
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if (!findMainSymbol())
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return false;
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calculateMainSize();
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logMainFunctionCode();
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logRelocations();
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if (!validateSections())
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return false;
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if (!patchAndSave())
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return false;
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return true;
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}
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};
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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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Patcher patcher;
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patcher.inputFile = inputFile;
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patcher.outputFile = outputFile;
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return patcher.run() ? 0 : 1;
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} |