欺骗你的小眼睛——Android 静默安装

忘是亡心i 2022-08-06 07:11 228阅读 0赞

我们一般代码调用安装apk会写下面的代码

Intent intent = new  Intent(Intent.ACTION_VIEW);
    File apkFile = new File(Environment.getExternalStorageDirectory().getAbsolutePath()+"/1.apk");
    intent.setDataAndType(Uri.fromFile(apkFile),"application/vnd.android.package-archive");
    startActivity(intent);

我们安装apk时系统会分析apk，然后弹出如下图的提示

![Image 1][]![Image 1][]

![Image 1][]

当我们点击安装后，系统会进行安装

这里我们查看系统源码来看一下系统是怎么执行安装程序的

首先我们找到**PackageInstallerActivity.java,**一看命名规则就知道是apk安装的界面

既然是Activity 那么我们首先来看onCreate()方法

@Override
        protected void onCreate(Bundle icicle) {
            super.onCreate(icicle);
            //get intent information  获取Intent信息
            final Intent intent = getIntent();
            mPackageURI = intent.getData();//apk的uri
            mPm = getPackageManager(); 
            mPkgInfo = PackageUtil.getPackageInfo(mPackageURI);
            
            // Check for parse errors 检查apk是否有错误
            if(mPkgInfo == null) {
                Log.w(TAG, "Parse error when parsing manifest. Discontinuing installation");
                showDialogInner(DLG_PACKAGE_ERROR);
                return;
            }
            
            //set view
            requestWindowFeature(Window.FEATURE_NO_TITLE);
            setContentView(R.layout.install_start); //这就是上面的界面
            mInstallConfirm = findViewById(R.id.install_confirm_panel);
            mInstallConfirm.setVisibility(View.INVISIBLE);
            PackageUtil.AppSnippet as = PackageUtil.getAppSnippet(this,
                    mPkgInfo.applicationInfo, mPackageURI);
            PackageUtil.initSnippetForNewApp(this, as, R.id.app_snippet);
           //check setting //是否设置了 允许安装未知来源，就是设置那里的
            if(!isInstallingUnknownAppsAllowed()) {
                //ask user to enable setting first
                showDialogInner(DLG_UNKNOWN_APPS);
                return;
            }
            initiateInstall();
        }

然后看initiateInstall（）方法

private void initiateInstall() {
            String pkgName = mPkgInfo.packageName;
            // Check if there is already a package on the device with this name
            // but it has been renamed to something else. //检查是否有相同包名的应用
            String[] oldName = mPm.canonicalToCurrentPackageNames(new String[] { pkgName });
            if (oldName != null && oldName.length > 0 && oldName[0] != null) {
                pkgName = oldName[0];
                mPkgInfo.setPackageName(pkgName);
            }
            // Check if package is already installed. display confirmation dialog if replacing pkg检查是否已经安装过了
            try {
                mAppInfo = mPm.getApplicationInfo(pkgName,
                        PackageManager.GET_UNINSTALLED_PACKAGES);
            } catch (NameNotFoundException e) {
                mAppInfo = null;
            }
            if (mAppInfo == null) {
                startInstallConfirm();//安装
            } else {
                if(localLOGV) Log.i(TAG, "Replacing existing package:"+
                        mPkgInfo.applicationInfo.packageName);
                showDialogInner(DLG_REPLACE_APP);
            }
        }

来到startInstallConfirm（）

private void startInstallConfirm() {
            LinearLayout permsSection = (LinearLayout) mInstallConfirm.findViewById(R.id.permissions_section);
            LinearLayout securityList = (LinearLayout) permsSection.findViewById(
                    R.id.security_settings_list);
            boolean permVisible = false;
            if(mPkgInfo != null) {
                AppSecurityPermissions asp = new AppSecurityPermissions(this, mPkgInfo);
                if(asp.getPermissionCount() > 0) {
                    permVisible = true;
                    securityList.addView(asp.getPermissionsView());
                }
            }
            if(!permVisible){
                permsSection.setVisibility(View.INVISIBLE);
            }
            mInstallConfirm.setVisibility(View.VISIBLE);
            mOk = (Button)findViewById(R.id.ok_button); //确认按钮
            mCancel = (Button)findViewById(R.id.cancel_button);
            mOk.setOnClickListener(this);
            mCancel.setOnClickListener(this);
        }

找点击事件 onClick()

public void onClick(View v) {
            if(v == mOk) { //开始安装，弹出安装进度界面
                // Start subactivity to actually install the application
                Intent newIntent = new Intent();
                newIntent.putExtra(PackageUtil.INTENT_ATTR_APPLICATION_INFO,
                        mPkgInfo.applicationInfo);
                newIntent.setData(mPackageURI);
                newIntent.setClass(this, InstallAppProgress.class); //这里调到了InstallAppProgress.java
                String installerPackageName = getIntent().getStringExtra(Intent.EXTRA_INSTALLER_PACKAGE_NAME);
                if (installerPackageName != null) {
                    newIntent.putExtra(Intent.EXTRA_INSTALLER_PACKAGE_NAME, installerPackageName);
                }
                if(localLOGV) Log.i(TAG, "downloaded app uri="+mPackageURI);
                startActivity(newIntent);
                finish();
            } else if(v == mCancel) {
                // Cancel and finish
                finish();
            }
        }

继续跟踪 到 InstallAppProgress.java 的onCreate()

@Override
        public void onCreate(Bundle icicle) {
            super.onCreate(icicle);
            Intent intent = getIntent();
            mAppInfo = intent.getParcelableExtra(PackageUtil.INTENT_ATTR_APPLICATION_INFO);
            mPackageURI = intent.getData();
            initView();
        }

initView();

public void initView() {
            requestWindowFeature(Window.FEATURE_NO_TITLE);
            setContentView(R.layout.op_progress);
            int installFlags = 0; //设置錐lag
            PackageManager pm = getPackageManager();
            try {
                PackageInfo pi = pm.getPackageInfo(mAppInfo.packageName, 
                        PackageManager.GET_UNINSTALLED_PACKAGES);
                if(pi != null) {
                    installFlags |= PackageManager.INSTALL_REPLACE_EXISTING; //替换已经存在的
                }
            } catch (NameNotFoundException e) {
            }
            if((installFlags & PackageManager.INSTALL_REPLACE_EXISTING )!= 0) {
                Log.w(TAG, "Replacing package:" + mAppInfo.packageName);
            }
            PackageUtil.AppSnippet as = PackageUtil.getAppSnippet(this, mAppInfo,
                    mPackageURI);
            mLabel = as.label;
            PackageUtil.initSnippetForNewApp(this, as, R.id.app_snippet);
            mStatusTextView = (TextView)findViewById(R.id.center_text);
            mStatusTextView.setText(R.string.installing);
            mProgressBar = (ProgressBar) findViewById(R.id.progress_bar);
            mProgressBar.setIndeterminate(true);
            // Hide button till progress is being displayed
            mOkPanel = (View)findViewById(R.id.buttons_panel);
            mDoneButton = (Button)findViewById(R.id.done_button);
            mLaunchButton = (Button)findViewById(R.id.launch_button);
            mOkPanel.setVisibility(View.INVISIBLE);
    
            String installerPackageName = getIntent().getStringExtra(
                    Intent.EXTRA_INSTALLER_PACKAGE_NAME);
            PackageInstallObserver observer = new PackageInstallObserver();
            pm.installPackage(mPackageURI, observer, installFlags, installerPackageName);//安装的代码
        }

几经周折，总算找到了。。。

下几句 关键的

int installFlags = 0; //设置Flag  
PackageManager pm = getPackageManager();  
try \{  
PackageInfo pi = pm.getPackageInfo(mAppInfo.packageName,  
PackageManager.GET\_UNINSTALLED\_PACKAGES);  
if(pi != null) \{  
installFlags |= PackageManager.INSTALL\_REPLACE\_EXISTING; //替换已经存在的  
\}  
\} catch (NameNotFoundException e) \{  
\}  
  
PackageUtil.AppSnippet as = PackageUtil.getAppSnippet(this, mAppInfo,  
mPackageURI);  
String installerPackageName = getIntent().getStringExtra(  
Intent.EXTRA\_INSTALLER\_PACKAGE\_NAME);  
PackageInstallObserver observer = new PackageInstallObserver();  
 pm.installPackage(mPackageURI, observer, installFlags, installerPackageName);//安装的代

我们可以通过上面的代码直接进行安装，

不过我们需要android.Manifest.permission\#INSTALL\_PACKAGE,

此权限只有system应用才能使用.

所以此应用必须放入system/app下,

解决思路

•将我们的应用伪装成系统的应用

实现步骤

•共享系统UID

•使用系统签名（匹配签名需要公钥和密钥两个文件生成keystore）

还有静默安装的一种方式是使用root权限 adb指令执行 install -r 进行安装

[Image 1]: