安卓so文件函数动态注册

定义一个js脚本，把他放进去就可以 

var ishook_libart = false;
//打印输出so文件运行时实际注册的函数。比如jadx里面的加密函数和打开so文件后搜到的函数不一致。这种情况用了混淆
//命令 frida -U -l hook_RegisterNatives.js -f com.coolapk.market --no-pause
// 打印的结果：[RegisterNatives] java_class: com.coolapk.market.util.AuthUtils name: getAS sig: (Landroid/content/Context;Ljava/lang/String;)Ljava/lang/String; fnPtr: 0xd30c1501 module_name: libnative-lib.so module_base: 0xd305b000 offset: 0x66501
//getAS是jadx里面的函数 offset 0x66501是函数 实际运行的偏移量。offset-1就是实际 的函数位置，我们用ida打开so文件，搜索66500就能定位到实际的函数运行地址
function hook_libart() {
    if (ishook_libart === true) {
        return;
    }
    var symbols = Module.enumerateSymbolsSync("libart.so");
    var addrGetStringUTFChars = null;
    var addrNewStringUTF = null;
    var addrFindClass = null;
    var addrGetMethodID = null;
    var addrGetStaticMethodID = null;
    var addrGetFieldID = null;
    var addrGetStaticFieldID = null;
    var addrRegisterNatives = null;
    var addrAllocObject = null;
    var addrCallObjectMethod = null;
    var addrGetObjectClass = null;
    var addrReleaseStringUTFChars = null;
    for (var i = 0; i < symbols.length; i++) {
        var symbol = symbols[i];
        if (symbol.name == "_ZN3art3JNI17GetStringUTFCharsEP7_JNIEnvP8_jstringPh") {
            addrGetStringUTFChars = symbol.address;
            console.log("GetStringUTFChars is at ", symbol.address, symbol.name);
        } else if (symbol.name == "_ZN3art3JNI12NewStringUTFEP7_JNIEnvPKc") {
            addrNewStringUTF = symbol.address;
            console.log("NewStringUTF is at ", symbol.address, symbol.name);
        } else if (symbol.name == "_ZN3art3JNI9FindClassEP7_JNIEnvPKc") {
            addrFindClass = symbol.address;
            console.log("FindClass is at ", symbol.address, symbol.name);
        } else if (symbol.name == "_ZN3art3JNI11GetMethodIDEP7_JNIEnvP7_jclassPKcS6_") {
            addrGetMethodID = symbol.address;
            console.log("GetMethodID is at ", symbol.address, symbol.name);
        } else if (symbol.name == "_ZN3art3JNI17GetStaticMethodIDEP7_JNIEnvP7_jclassPKcS6_") {
            addrGetStaticMethodID = symbol.address;
            console.log("GetStaticMethodID is at ", symbol.address, symbol.name);
        } else if (symbol.name == "_ZN3art3JNI10GetFieldIDEP7_JNIEnvP7_jclassPKcS6_") {
            addrGetFieldID = symbol.address;
            console.log("GetFieldID is at ", symbol.address, symbol.name);
        } else if (symbol.name == "_ZN3art3JNI16GetStaticFieldIDEP7_JNIEnvP7_jclassPKcS6_") {
            addrGetStaticFieldID = symbol.address;
            console.log("GetStaticFieldID is at ", symbol.address, symbol.name);
        } else if (symbol.name == "_ZN3art3JNI15RegisterNativesEP7_JNIEnvP7_jclassPK15JNINativeMethodi") {
            addrRegisterNatives = symbol.address;
            console.log("RegisterNatives is at ", symbol.address, symbol.name);
        } else if (symbol.name.indexOf("_ZN3art3JNI11AllocObjectEP7_JNIEnvP7_jclass") >= 0) {
            addrAllocObject = symbol.address;
            console.log("AllocObject is at ", symbol.address, symbol.name);
        }  else if (symbol.name.indexOf("_ZN3art3JNI16CallObjectMethodEP7_JNIEnvP8_jobjectP10_jmethodIDz") >= 0) {
            addrCallObjectMethod = symbol.address;
            console.log("CallObjectMethod is at ", symbol.address, symbol.name);
        } else if (symbol.name.indexOf("_ZN3art3JNI14GetObjectClassEP7_JNIEnvP8_jobject") >= 0) {
            addrGetObjectClass = symbol.address;
            console.log("GetObjectClass is at ", symbol.address, symbol.name);
        } else if (symbol.name.indexOf("_ZN3art3JNI21ReleaseStringUTFCharsEP7_JNIEnvP8_jstringPKc") >= 0) {
            addrReleaseStringUTFChars = symbol.address;
            console.log("ReleaseStringUTFChars is at ", symbol.address, symbol.name);
        }
    }

    if (addrRegisterNatives != null) {
        Interceptor.attach(addrRegisterNatives, {
            onEnter: function (args) {
                console.log("[RegisterNatives] method_count:", args[3]);
                var env = args[0];
                var java_class = args[1];
                
                var funcAllocObject = new NativeFunction(addrAllocObject, "pointer", ["pointer", "pointer"]);
                var funcGetMethodID = new NativeFunction(addrGetMethodID, "pointer", ["pointer", "pointer", "pointer", "pointer"]);
                var funcCallObjectMethod = new NativeFunction(addrCallObjectMethod, "pointer", ["pointer", "pointer", "pointer"]);
                var funcGetObjectClass = new NativeFunction(addrGetObjectClass, "pointer", ["pointer", "pointer"]);
                var funcGetStringUTFChars = new NativeFunction(addrGetStringUTFChars, "pointer", ["pointer", "pointer", "pointer"]);
                var funcReleaseStringUTFChars = new NativeFunction(addrReleaseStringUTFChars, "void", ["pointer", "pointer", "pointer"]);

                var clz_obj = funcAllocObject(env, java_class);
                var mid_getClass = funcGetMethodID(env, java_class, Memory.allocUtf8String("getClass"), Memory.allocUtf8String("()Ljava/lang/Class;"));
                var clz_obj2 = funcCallObjectMethod(env, clz_obj, mid_getClass);
                var cls = funcGetObjectClass(env, clz_obj2);
                var mid_getName = funcGetMethodID(env, cls, Memory.allocUtf8String("getName"), Memory.allocUtf8String("()Ljava/lang/String;"));
                var name_jstring = funcCallObjectMethod(env, clz_obj2, mid_getName);
                var name_pchar = funcGetStringUTFChars(env, name_jstring, ptr(0));
                var class_name = ptr(name_pchar).readCString();
                funcReleaseStringUTFChars(env, name_jstring, name_pchar);

                //console.log(class_name);

                var methods_ptr = ptr(args[2]);

                var method_count = parseInt(args[3]);
                for (var i = 0; i < method_count; i++) {
                    var name_ptr = Memory.readPointer(methods_ptr.add(i * Process.pointerSize * 3));
                    var sig_ptr = Memory.readPointer(methods_ptr.add(i * Process.pointerSize * 3 + Process.pointerSize));
                    var fnPtr_ptr = Memory.readPointer(methods_ptr.add(i * Process.pointerSize * 3 + Process.pointerSize * 2));

                    var name = Memory.readCString(name_ptr);
                    var sig = Memory.readCString(sig_ptr);
                    var find_module = Process.findModuleByAddress(fnPtr_ptr);
                    console.log("[RegisterNatives] java_class:", class_name, "name:", name, "sig:", sig, "fnPtr:", fnPtr_ptr, "module_name:", find_module.name, "module_base:", find_module.base, "offset:", ptr(fnPtr_ptr).sub(find_module.base));

                }
            },
            onLeave: function (retval) { }
        });
    }

    ishook_libart = true;
}

hook_libart();