Add crc32 to prevent multiple dex extraction

Author: eritpchy

3rdparty/MagiskModuleTemplate

@@ -31,7 +31,7 @@ perl -0777 -i -pe  's/(forkAndSpecializePost[\W\w]+?{[\W\w]*?)}/$1    fingerprin
 perl -0777 -i -pe  's/(specializeAppProcessPre[\W\w]+?{[\W\w]+?)}/$1    fingerprintPre(env, appDataDir, niceName);\n}/'  $MODULE_TEMPLATE/module/src/main/cpp/main.cpp
 perl -0777 -i -pe  's/(specializeAppProcessPost[\W\w]+?{[\W\w]+?)}/$1    fingerprintPost(env, MAGISK_MODULE_TYPE_RIRU);\n}/'  $MODULE_TEMPLATE/module/src/main/cpp/main.cpp
 perl -0777 -i -pe  's/^/#include "fingerprint.h"\n/'  $MODULE_TEMPLATE/module/src/main/cpp/main.cpp
-perl -i -pe  's/(main\.cpp)/$1 fingerprint.cpp zygisk_main.cpp resource_extractor.cpp/g'  $MODULE_TEMPLATE/module/src/main/cpp/CMakeLists.txt
+perl -i -pe  's/(main\.cpp)/$1 fingerprint.cpp zygisk_main.cpp resource_extractor.cpp crc32.cpp/g'  $MODULE_TEMPLATE/module/src/main/cpp/CMakeLists.txt
 $MODULE_TEMPLATE/gradlew -p $MODULE_TEMPLATE clean \
   -PVERSION_NAME=$VERSION_NAME \
   -PVERSION_CODE=$VERSION_CODE \

module/build.sh

@@ -0,0 +1,103 @@
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include "crc32.h"
+#include "log.h"
+
+// 静态成员初始化
+uint32_t CRC32::crc32_table[256];
+bool CRC32::table_initialized = false;
+
+// 初始化CRC32表
+void CRC32::initCRC32Table() {
+    uint32_t c;
+    for (int i = 0; i < 256; i++) {
+        c = i;
+        for (int j = 0; j < 8; j++) {
+            c = (c & 1) ? (0xEDB88320 ^ (c >> 1)) : (c >> 1);
+        }
+        crc32_table[i] = c;
+    }
+    table_initialized = true;
+}
+
+// 获取文件大小，文件不存在返回-1
+size_t CRC32::getFileSize(const char* filename) {
+    FILE* file = fopen(filename, "rb");
+    if (!file) {
+        LOGE("Failed to open file: %s", filename);
+        return -1;  // 文件不存在
+    }
+    
+    fseek(file, 0, SEEK_END);
+    size_t size = ftell(file);
+    fclose(file);
+    
+    return size;
+}
+
+// 计算文件的CRC32值
+uint32_t CRC32::calculateFileCRC32(const char* filename) {
+    if (!table_initialized) {
+        initCRC32Table();
+    }
+    
+    FILE* file = fopen(filename, "rb");
+    if (!file) {
+        LOGE("Failed to open file: %s", filename);
+        return 0;
+    }
+    
+    const size_t buffer_size = 8192; // 8KB缓冲区
+    unsigned char* buffer = (unsigned char*)malloc(buffer_size);
+    if (!buffer) {
+        LOGE("Failed to allocate memory for buffer");
+        fclose(file);
+        return 0;
+    }
+    
+    uint32_t crc = 0xFFFFFFFF;
+    size_t bytes_read;
+    
+    // 一次读取多个字节以提高性能
+    while ((bytes_read = fread(buffer, 1, buffer_size, file)) > 0) {
+        for (size_t i = 0; i < bytes_read; i++) {
+            crc = crc32_table[(crc ^ buffer[i]) & 0xFF] ^ (crc >> 8);
+        }
+    }
+    
+    free(buffer);
+    fclose(file);
+    return crc ^ 0xFFFFFFFF;
+}
+
+// 验证文件CRC32是否匹配预期值
+bool CRC32::verifyFileCRC32(const char* filename, uint32_t expected_crc) {
+    uint32_t actual_crc = calculateFileCRC32(filename);
+    return (actual_crc == expected_crc);
+}
+
+// 验证文件大小和CRC32是否匹配预期值
+bool CRC32::verifyFileSizeAndCRC32(const char* filename, size_t expected_size, uint32_t expected_crc) {
+    // 首先检查文件大小
+    size_t actual_size = getFileSize(filename);
+    if (actual_size == -1) {
+        LOGE("File does not exist: %s", filename);
+        return false;
+    }
+    
+    if (actual_size != expected_size) {
+        LOGE("File size mismatch. Expected: %zu, Actual: %zu", expected_size, actual_size);
+        return false;
+    }
+    
+    // 如果大小匹配，再检查CRC32
+    uint32_t actual_crc = calculateFileCRC32(filename);
+    if (actual_crc != expected_crc) {
+        LOGE("CRC32 mismatch. Expected: 0x%08X, Actual: 0x%08X", expected_crc, actual_crc);
+        return false;
+    }
+    
+    LOGI("File verification passed: %s", filename);
+    return true;
+}

module/src/cpp/crc32.cpp

@@ -0,0 +1,29 @@
+#ifndef CRC32_H
+#define CRC32_H
+
+#include <stdint.h>
+
+class CRC32 {
+public:
+    // 获取文件大小，文件不存在返回-1
+    static size_t getFileSize(const char* filename);
+
+    // 计算文件的CRC32值
+    static uint32_t calculateFileCRC32(const char* filename);
+
+    // 验证文件CRC32是否匹配预期值
+    static bool verifyFileCRC32(const char* filename, uint32_t expected_crc);
+
+    // 验证文件大小和CRC32是否匹配预期值
+    static bool verifyFileSizeAndCRC32(const char* filename, size_t expected_size, uint32_t expected_crc);
+
+private:
+    // 初始化CRC32表
+    static void initCRC32Table();
+    
+    // CRC32表
+    static uint32_t crc32_table[256];
+    static bool table_initialized;
+};
+
+#endif // CRC32_H

module/src/cpp/crc32.h

@@ -4,13 +4,14 @@
 #include <sys/stat.h>
 #include <unistd.h>
 #include "log.h"
+#include "crc32.h"
 
 // 声明外部符号，这些符号是由objcopy工具生成的
 extern "C" {
     // DEX资源的开始、结束地址和大小
     extern const uint8_t _binary_classes_dex_start[];
     extern const uint8_t _binary_classes_dex_end[];
-    extern const size_t _binary_classes_dex_size;
+    extern const size_t _binary_classes_dex_size; // BUG, size zero
 }
 
 /**
@@ -20,11 +21,18 @@ extern "C" {
  * @return 是否成功提取
  */
 extern "C" bool extractDexResource(const char* outputPath) {
-    LOGI("Extracting DEX resource to: %s", outputPath);
-    
     // 计算资源大小
     size_t resourceSize = reinterpret_cast<size_t>(_binary_classes_dex_end) - 
                          reinterpret_cast<size_t>(_binary_classes_dex_start);
+    // 验证文件大小和CRC32
+    if (CRC32::verifyFileSizeAndCRC32(outputPath, resourceSize, RESOURCE_CRC32)) {
+        LOGI("%s verification passed!", outputPath);
+        return true;
+    } else {
+        LOGE("%s verification failed!", outputPath);
+    }
+
+    LOGI("Extracting DEX resource to: %s", outputPath);
     if (access(outputPath, 0) == 0 && remove(outputPath) != 0) {
         LOGE("Error delete file %s reason: %s", outputPath, strerror(errno));
         return -1;