安卓应用安全指南 4.1.1 创建/使用活动示例代码

4.1.1 创建/使用活动示例代码

原书：Android Application Secure Design/Secure Coding Guidebook

译者：飞龙

协议：CC BY-NC-SA 4.0

使用活动的风险和对策取决于活动的使用方式。在本节中，我们根据活动的使用情况，对 4 种活动进行了分类。你可以通过下面的图表来找出，你应该创建哪种类型的活动。由于安全编程最佳实践根据活动的使用方式而有所不同，因此我们也将解释活动的实现。

表 4-1 活动类型的定义

类型	定义
私有	不能由其他应用加载，所以是最安全的活动
公共	应该由很多未指定的应用使用的活动
伙伴	只能由可信的伙伴公司开发的应用使用的活动
内部	只能由其他内部应用使用的活动

4.1.1.1 创建/使用私有活动

私有活动是其他应用程序无法启动的活动，因此它是最安全的活动。

当使用仅在应用程序中使用的活动（私有活动）时，只要你对类使用显示意图，那么你不必担心将它意外发送到任何其他应用程序。但是，第三方应用程序可能会读取用于启动活动的意图。因此，如果你将敏感信息放入用于启动活动的意图中，有必要采取对策，来确保它不会被恶意第三方读取。

下面展示了如何创建私有活动的示例代码。

要点（创建活动）：

1) 不要指定taskAffinity。

2) 不要指定launchMode。

3) 将导出属性明确设置为false。

4) 仔细和安全地处理收到的意图，即使意图从相同的应用发送。

5) 敏感信息可以发送，因为它发送和接收所有同一应用中的信息。

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"package="org.jssec.android.activity.privateactivity" ><application
        android:allowBackup="false"android:icon="@drawable/ic_launcher"android:label="@string/app_name" ><!-- Private activity --><!-- *** POINT 1 *** Do not specify taskAffinity --><!-- *** POINT 2 *** Do not specify launchMode --><!-- *** POINT 3 *** Explicitly set the exported attribute to false. --><activity
            android:name=".PrivateActivity"android:label="@string/app_name"android:exported="false" /><!-- Public activity launched by launcher --><activity
            android:name=".PrivateUserActivity"android:label="@string/app_name"android:exported="true" ><intent-filter><action android:name="android.intent.action.MAIN" /><category android:name="android.intent.category.LAUNCHER" /></intent-filter></activity></application>
</manifest>

PrivateActivity.java

package org.jssec.android.activity.privateactivity;import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;public class PrivateActivity extends Activity {@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.private_activity);// *** POINT 4 *** Handle the received Intent carefully and securely, even though the Intent was sent from the same application.// Omitted, since this is a sample. Please refer to "3.2 Handling Input Data Carefully and Securely."String param = getIntent().getStringExtra("PARAM");Toast.makeText(this, String.format("Received param: ￥"%s￥"", param), Toast.LENGTH_LONG).show();}public void onReturnResultClick(View view) {// *** POINT 5 *** Sensitive information can be sent since it is sending and receiving all within the same application.Intent intent = new Intent();intent.putExtra("RESULT", "Sensitive Info");setResult(RESULT_OK, intent);finish();}
}

下面展示如何使用私有活动的示例代码。

要点（使用活动）；

6) 不要为意图设置FLAG_ACTIVITY_NEW_TASK标志来启动活动。

7) 使用显式意图，以及用于调用相同应用中的活动的特定的类。

8) 由于目标活动位于同一个应用中，因此只能通过putExtra()发送敏感信息 [1]。

警告：如果不遵守第 1, 2 和 6 点，第三方可能会读到意图。更多详细信息，请参阅第 4.1.2.2 和 4.1.2.3 节。

9) 即使数据来自同一应用中的活动，也要小心并安全地处理收到的结果数据。

PrivateUserActivity.java

package org.jssec.android.activity.privateactivity;import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;public class PrivateUserActivity extends Activity {private static final int REQUEST_CODE = 1;@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.user_activity);}public void onUseActivityClick(View view) {// *** POINT 6 *** Do not set the FLAG_ACTIVITY_NEW_TASK flag for intents to start an activity.// *** POINT 7 *** Use the explicit Intents with the class specified to call an activity in the same application.Intent intent = new Intent(this, PrivateActivity.class);// *** POINT 8 *** Sensitive information can be sent only by putExtra() since the destination activity is in the same application.intent.putExtra("PARAM", "Sensitive Info");startActivityForResult(intent, REQUEST_CODE);}@Overridepublic void onActivityResult(int requestCode, int resultCode, Intent data) {super.onActivityResult(requestCode, resultCode, data);if (resultCode != RESULT_OK) return;switch (requestCode) {case REQUEST_CODE:String result = data.getStringExtra("RESULT");// *** POINT 9 *** Handle the received data carefully and securely,// even though the data comes from an activity within the same application.// Omitted, since this is a sample. Please refer to "3.2 Handling Input Data Carefully and Securely."Toast.makeText(this, String.format("Received result: ￥"%s￥"", result), Toast.LENGTH_LONG).show();break;}}
}

4.1.1.2 创建/使用公共活动

公共活动是应该由大量未指定的应用程序使用的活动。有必要注意的是，公共活动可能收到恶意软件发送的意图。另外，使用公共活动时，有必要注意恶意软件也可以接收或阅读发送给他们的意图。

要点（创建活动）：

1) 将导出属性显式设置为true。

2) 小心并安全地处理接收到的意图。

3) 返回结果时，请勿包含敏感信息。

下面展示了创建公共活动的示例代码。

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"package="org.jssec.android.activity.publicactivity" ><application
        android:allowBackup="false"android:icon="@drawable/ic_launcher"android:label="@string/app_name" ><!-- Public Activity --><!-- *** POINT 1 *** Explicitly set the exported attribute to true. --><activity
            android:name=".PublicActivity"android:label="@string/app_name"android:exported="true"><!-- Define intent filter to receive an implicit intent for a specified action --><intent-filter><action android:name="org.jssec.android.activity.MY_ACTION" /><category android:name="android.intent.category.DEFAULT" /></intent-filter></activity></application>
</manifest>

PublicActivity.java

package org.jssec.android.activity.publicactivity;import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;public class PublicActivity extends Activity {@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);// *** POINT 2 *** Handle the received intent carefully and securely.// Since this is a public activity, it is possible that the sending application may be malware.// Omitted, since this is a sample. Please refer to "3.2 Handling Input Data Carefully and Securely."String param = getIntent().getStringExtra("PARAM");Toast.makeText(this, String.format("Received param: ¥"%s¥"", param), Toast.LENGTH_LONG).show();}public void onReturnResultClick(View view) {// *** POINT 3 *** When returning a result, do not include sensitive information.// Since this is a public activity, it is possible that the receiving application may be malware.// If there is no problem if the data gets received by malware, then it can be returned as a result.Intent intent = new Intent();intent.putExtra("RESULT", "Not Sensitive Info");setResult(RESULT_OK, intent);finish();}
}

接下来，这里是公共活动用户端的示例代码。

要点（使用活动）：

4) 不要发送敏感信息。

5) 收到结果时，请仔细并安全地处理数据。

PublicUserActivity.java

package org.jssec.android.activity.publicuser;
import android.app.Activity;
import android.content.ActivityNotFoundException;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;
public class PublicUserActivity extends Activity {private static final int REQUEST_CODE = 1;@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);}public void onUseActivityClick(View view) {try {// *** POINT 4 *** Do not send sensitive information.Intent intent = new Intent("org.jssec.android.activity.MY_ACTION");intent.putExtra("PARAM", "Not Sensitive Info");startActivityForResult(intent, REQUEST_CODE);} catch (ActivityNotFoundException e) {Toast.makeText(this, "Target activity not found.", Toast.LENGTH_LONG).show();}}@Overridepublic void onActivityResult(int requestCode, int resultCode, Intent data) {super.onActivityResult(requestCode, resultCode, data);// *** POINT 5 *** When receiving a result, handle the data carefully and securely.// Omitted, since this is a sample. Please refer to "3.2 Handling Input Data Carefully and Securely."if (resultCode != RESULT_OK) return;switch (requestCode) {case REQUEST_CODE:String result = data.getStringExtra("RESULT");Toast.makeText(this, String.format("Received result: ¥"%s¥"", result), Toast.LENGTH_LONG).show();break;}}
}
```#### 4.1.1.3 创建/使用伙伴活动伙伴活动是只能由特定应用程序使用的活动。 它们在想要安全共享信息和功能的伙伴公司之间使用。 第三方应用程序可能会读取用于启动活动的意图。 因此，如果你将敏感信息放入用于启动活动的意图中，有必要采取对策来确保其无法被恶意第三方读取。创建伙伴活动的示例代码如下所示。要点（创建活动）：1) 不要指定`taskAffinity`。2) 不要指定`launchMode`。3) 不要定义意图过滤器，并将导出属性明确设置为`true`。4) 通过预定义白名单验证请求应用程序的证书。5) 尽管意图是从伙伴应用程序发送的，仔细和安全地处理接收到的意图。6) 只返回公开给伙伴应用的信息。请参阅“4.1.3.2 验证和请求应用”，了解如何通过白名单验证应用。 此外，请参阅“5.2.1.3 如何验证应用证书的哈希”，了解如何验证白名单中指定目标应用的证书哈希。AndroidManifest.xml<div class="se-preview-section-delimiter"></div>```xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:layout_width="fill_parent"android:layout_height="fill_parent"android:orientation="vertical"android:padding="5dp" ><TextViewandroid:layout_width="fill_parent"android:layout_height="wrap_content"android:layout_marginTop="20dp"android:text="@string/description" /><Buttonandroid:layout_width="fill_parent"android:layout_height="wrap_content"android:layout_marginTop="20dp"android:onClick="onReturnResultClick"android:text="@string/return_result" />
</LinearLayout>

PartnerActivity.java

package org.jssec.android.activity.partneractivity;import org.jssec.android.shared.PkgCertWhitelists;
import org.jssec.android.shared.Utils;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;public class PartnerActivity extends Activity {// *** POINT 4 *** Verify the requesting application's certificate through a predefined whitelist.private static PkgCertWhitelists sWhitelists = null;private static void buildWhitelists(Context context) {boolean isdebug = Utils.isDebuggable(context);sWhitelists = new PkgCertWhitelists();// Register certificate hash value of partner application org.jssec.android.activity.partneruser.sWhitelists.add("org.jssec.android.activity.partneruser", isdebug ?// Certificate hash value of "androiddebugkey" in the debug.keystore."0EFB7236 328348A9 89718BAD DF57F544 D5CCB4AE B9DB34BC 1E29DD26 F77C8255" :// Certificate hash value of "partner key" in the keystore."1F039BB5 7861C27A 3916C778 8E78CE00 690B3974 3EB8259F E2627B8D 4C0EC35A");// Register the other partner applications in the same way.}private static boolean checkPartner(Context context, String pkgname) {if (sWhitelists == null) buildWhitelists(context);return sWhitelists.test(context, pkgname);}@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);// *** POINT 4 *** Verify the requesting application's certificate through a predefined whitelist.if (!checkPartner(this, getCallingActivity().getPackageName())) {Toast.makeText(this,"Requesting application is not a partner application.",Toast.LENGTH_LONG).show();finish();return;}// *** POINT 5 *** Handle the received intent carefully and securely, even though the intent was sent from a partner application.// Omitted, since this is a sample. Refer to "3.2 Handling Input Data Carefully and Securely."Toast.makeText(this, "Accessed by Partner App", Toast.LENGTH_LONG).show();}public void onReturnResultClick(View view) {// *** POINT 6 *** Only return Information that is granted to be disclosed to a partner application.Intent intent = new Intent();intent.putExtra("RESULT", "Information for partner applications");setResult(RESULT_OK, intent);finish();}
}

PkgCertWhitelists.java

package org.jssec.android.shared;import java.util.HashMap;
import java.util.Map;
import android.content.Context;public class PkgCertWhitelists {private Map<String, String> mWhitelists = new HashMap<String, String>();public boolean add(String pkgname, String sha256) {if (pkgname == null) return false;if (sha256 == null) return false;sha256 = sha256.replaceAll(" ", "");if (sha256.length() != 64) return false; // SHA-256 -> 32 bytes -> 64 charssha256 = sha256.toUpperCase();if (sha256.replaceAll("[0-9A-F]+", "").length() != 0) return false; // found non hex charmWhitelists.put(pkgname, sha256);return true;}public boolean test(Context ctx, String pkgname) {// Get the correct hash value which corresponds to pkgname.String correctHash = mWhitelists.get(pkgname);// Compare the actual hash value of pkgname with the correct hash value.return PkgCert.test(ctx, pkgname, correctHash);}
}

PkgCert.java

package org.jssec.android.shared;import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import android.content.Context;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.content.pm.PackageManager.NameNotFoundException;
import android.content.pm.Signature;public class PkgCert {public static boolean test(Context ctx, String pkgname, String correctHash) {if (correctHash == null) return false;correctHash = correctHash.replaceAll(" ", "");return correctHash.equals(hash(ctx, pkgname));}public static String hash(Context ctx, String pkgname) {if (pkgname == null) return null;try {PackageManager pm = ctx.getPackageManager();PackageInfo pkginfo = pm.getPackageInfo(pkgname, PackageManager.GET_SIGNATURES);if (pkginfo.signatures.length != 1) return null; // Will not handle multiple signatures.Signature sig = pkginfo.signatures[0];byte[] cert = sig.toByteArray();byte[] sha256 = computeSha256(cert);return byte2hex(sha256);} catch (NameNotFoundException e) {return null;}}private static byte[] computeSha256(byte[] data) {try {return MessageDigest.getInstance("SHA-256").digest(data);} catch (NoSuchAlgorithmException e) {return null;}}private static String byte2hex(byte[] data) {if (data == null) return null;final StringBuilder hexadecimal = new StringBuilder();for (final byte b : data) {hexadecimal.append(String.format("%02X", b));}return hexadecimal.toString();}
}

使用伙伴活动的示例代码如下：

7) 验证目标应用的证书是否已在白名单中注册。

8) 不要为启动活动的意图设置FLAG_ACTIVITY_NEW_TASK标志。

9) 仅通过putExtra()发送公开给伙伴活动的信息。

10) 使用显示意图调用伙伴活动。

11) 使用startActivityForResult()来调用伙伴活动。

12) 即使数据来自伙伴应用程序，也要小心并安全地处理收到的结果数据。

请参阅“4.1.3.2 验证请求应用”了解如何通过白名单验证应用程序。另请参阅“5.2.1.3 如何验证应用证书的哈希”，了解如何验证白名单中指定目标应用的证书哈希。

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"package="org.jssec.android.activity.partneruser" ><application
        android:allowBackup="false"android:icon="@drawable/ic_launcher"android:label="@string/app_name" ><activity
            android:name="org.jssec.android.activity.partneruser.PartnerUserActivity"android:label="@string/app_name"android:exported="true" ><intent-filter><action android:name="android.intent.action.MAIN" /><category android:name="android.intent.category.LAUNCHER" /></intent-filter></activity></application>
</manifest>

PartnerUserActivity.java

package org.jssec.android.activity.partneruser;import org.jssec.android.shared.PkgCertWhitelists;
import org.jssec.android.shared.Utils;
import android.app.Activity;
import android.content.ActivityNotFoundException;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;public class PartnerUserActivity extends Activity {// *** POINT 7 *** Verify if the certificate of a target application has been registered in a whitelist.private static PkgCertWhitelists sWhitelists = null;private static void buildWhitelists(Context context) {boolean isdebug = Utils.isDebuggable(context);sWhitelists = new PkgCertWhitelists();// Register the certificate hash value of partner application org.jssec.android.activity.partneractivity.sWhitelists.add("org.jssec.android.activity.partneractivity", isdebug ?// The certificate hash value of "androiddebugkey" is in debug.keystore."0EFB7236 328348A9 89718BAD DF57F544 D5CCB4AE B9DB34BC 1E29DD26 F77C8255" :// The certificate hash value of "my company key" is in the keystore."D397D343 A5CBC10F 4EDDEB7C A10062DE 5690984F 1FB9E88B D7B3A7C2 42E142CA");// Register the other partner applications in the same way.}private static boolean checkPartner(Context context, String pkgname) {if (sWhitelists == null) buildWhitelists(context);return sWhitelists.test(context, pkgname);}private static final int REQUEST_CODE = 1;// Information related the target partner activityprivate static final String TARGET_PACKAGE = "org.jssec.android.activity.partneractivity";private static final String TARGET_ACTIVITY = "org.jssec.android.activity.partneractivity.PartnerActivity";@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);}public void onUseActivityClick(View view) {// *** POINT 7 *** Verify if the certificate of the target application has been registered in the own white list.if (!checkPartner(this, TARGET_PACKAGE)) {Toast.makeText(this, "Target application is not a partner application.", Toast.LENGTH_LONG).show();return;}try {// *** POINT 8 *** Do not set the FLAG_ACTIVITY_NEW_TASK flag for the intent that start an activity.Intent intent = new Intent();// *** POINT 9 *** Only send information that is granted to be disclosed to a Partner Activity only by putExtra().intent.putExtra("PARAM", "Info for Partner Apps");// *** POINT 10 *** Use explicit intent to call a Partner Activity.intent.setClassName(TARGET_PACKAGE, TARGET_ACTIVITY);// *** POINT 11 *** Use startActivityForResult() to call a Partner Activity.startActivityForResult(intent, REQUEST_CODE);}catch (ActivityNotFoundException e) {Toast.makeText(this, "Target activity not found.", Toast.LENGTH_LONG).show();}}@Overridepublic void onActivityResult(int requestCode, int resultCode, Intent data) {super.onActivityResult(requestCode, resultCode, data);if (resultCode != RESULT_OK) return;switch (requestCode) {case REQUEST_CODE:String result = data.getStringExtra("RESULT");// *** POINT 12 *** Handle the received data carefully and securely,// even though the data comes from a partner application.// Omitted, since this is a sample. Please refer to "3.2 Handling Input Data Carefully and Securely."Toast.makeText(this,String.format("Received result: ¥"%s¥"", result), Toast.LENGTH_LONG).show();break;}}
}

PkgCertWhitelists.java

package org.jssec.android.shared;import java.util.HashMap;
import java.util.Map;
import android.content.Context;public class PkgCertWhitelists {private Map<String, String> mWhitelists = new HashMap<String, String>();public boolean add(String pkgname, String sha256) {if (pkgname == null) return false;if (sha256 == null) return false;sha256 = sha256.replaceAll(" ", "");if (sha256.length() != 64) return false; // SHA-256 -> 32 bytes -> 64 charssha256 = sha256.toUpperCase();if (sha256.replaceAll("[0-9A-F]+", "").length() != 0) return false; // found non hex charmWhitelists.put(pkgname, sha256);return true;}public boolean test(Context ctx, String pkgname) {// Get the correct hash value which corresponds to pkgname.String correctHash = mWhitelists.get(pkgname);// Compare the actual hash value of pkgname with the correct hash value.return PkgCert.test(ctx, pkgname, correctHash);}
}

PkgCert.java

package org.jssec.android.shared;import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import android.content.Context;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.content.pm.PackageManager.NameNotFoundException;
import android.content.pm.Signature;public class PkgCert {public static boolean test(Context ctx, String pkgname, String correctHash) {if (correctHash == null) return false;correctHash = correctHash.replaceAll(" ", "");return correctHash.equals(hash(ctx, pkgname));}public static String hash(Context ctx, String pkgname) {if (pkgname == null) return null;try {PackageManager pm = ctx.getPackageManager();PackageInfo pkginfo = pm.getPackageInfo(pkgname, PackageManager.GET_SIGNATURES);if (pkginfo.signatures.length != 1) return null; // Will not handle multiple signatures.Signature sig = pkginfo.signatures[0];byte[] cert = sig.toByteArray();byte[] sha256 = computeSha256(cert);return byte2hex(sha256);} catch (NameNotFoundException e) {return null;}}private static byte[] computeSha256(byte[] data) {try {return MessageDigest.getInstance("SHA-256").digest(data);} catch (NoSuchAlgorithmException e) {return null;}}private static String byte2hex(byte[] data) {if (data == null) return null;final StringBuilder hexadecimal = new StringBuilder();for (final byte b : data) {hexadecimal.append(String.format("%02X", b));}return hexadecimal.toString();}
}

4.1.1.4 创建/使用内部活动

内部活动是禁止其他内部应用以外的应用使用的活动。它们用于内部开发的应用，以便安全地共享信息和功能。

第三方应用可能会读取用于启动活动的意图。因此，如果你将敏感信息放入用于启动活动的意图中，有必要采取对策来确保它不会被恶意第三方读取。

下面展示了创建内部活动的示例代码。

要点（创建活动）：

1) 定义内部签名权限。

2) 不要指定taskAffinity。

3) 不要指定launchMode。

4) 需要内部签名权限。

5) 不要定义意图过滤器，并将导出属性显式设为true。

6) 确认内部签名权限是由内部应用的。

7) 尽管意图是从内部应用发送的，仔细和安全地处理接收到的意图。

8) 由于请求的应用是内部的，因此可以返回敏感信息。

9) 导出 APK 时，请使用与目标应用相同的开发人员密钥对 APK 进行签名。

AndroidManifest.xml


<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"package="org.jssec.android.activity.inhouseactivity" ><!-- *** POINT 1 *** Define an in-house signature permission --><permission
    android:name="org.jssec.android.activity.inhouseactivity.MY_PERMISSION"android:protectionLevel="signature" /><application
        android:allowBackup="false"android:icon="@drawable/ic_launcher"android:label="@string/app_name" ><!-- In-house Activity --><!-- *** POINT 2 *** Do not specify taskAffinity --><!-- *** POINT 3 *** Do not specify launchMode --><!-- *** POINT 4 *** Require the in-house signature permission --><!-- *** POINT 5 *** Do not define the intent filter and explicitly set the exported attribute totrue --><activity
            android:name="org.jssec.android.activity.inhouseactivity.InhouseActivity"android:exported="true"android:permission="org.jssec.android.activity.inhouseactivity.MY_PERMISSION" /></application>
</manifest>

InhouseActivity.java

package org.jssec.android.activity.inhouseactivity;import org.jssec.android.shared.SigPerm;
import org.jssec.android.shared.Utils;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;public class InhouseActivity extends Activity {// In-house Signature Permissionprivate static final String MY_PERMISSION = "org.jssec.android.activity.inhouseactivity.MY_PERMISSION";// In-house certificate hash valueprivate static String sMyCertHash = null;private static String myCertHash(Context context) {if (sMyCertHash == null) {if (Utils.isDebuggable(context)) {// Certificate hash value of "androiddebugkey" in the debug.keystore.sMyCertHash = "0EFB7236 328348A9 89718BAD DF57F544 D5CCB4AE B9DB34BC 1E29DD26 F77C8255";} else {// Certificate hash value of "my company key" in the keystore.sMyCertHash = "D397D343 A5CBC10F 4EDDEB7C A10062DE 5690984F 1FB9E88B D7B3A7C2 42E142CA";}}return sMyCertHash;}@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);// *** POINT 6 *** Verify that the in-house signature permission is defined by an in-house application.if (!SigPerm.test(this, MY_PERMISSION, myCertHash(this))) {Toast.makeText(this, "The in-house signature permission is not declared by in-house application.",Toast.LENGTH_LONG).show();finish();return;}// *** POINT 7 *** Handle the received intent carefully and securely, even though the intent was sent from an in-house application.// Omitted, since this is a sample. Please refer to "3.2 Handling Input Data Carefully and Securely."String param = getIntent().getStringExtra("PARAM");Toast.makeText(this, String.format("Received param: ¥"%s¥"", param), Toast.LENGTH_LONG).show();}public void onReturnResultClick(View view) {// *** POINT 8 *** Sensitive information can be returned since the requesting application is inhouse.Intent intent = new Intent();intent.putExtra("RESULT", "Sensitive Info");setResult(RESULT_OK, intent);finish();}
}

SigPerm.java

package org.jssec.android.shared;import android.content.Context;
import android.content.pm.PackageManager;
import android.content.pm.PackageManager.NameNotFoundException;
import android.content.pm.PermissionInfo;public class SigPerm {public static boolean test(Context ctx, String sigPermName, String correctHash) {if (correctHash == null) return false;correctHash = correctHash.replaceAll(" ", "");return correctHash.equals(hash(ctx, sigPermName));}public static String hash(Context ctx, String sigPermName) {if (sigPermName == null) return null;try {// Get the package name of the application which declares a permission named sigPermName.PackageManager pm = ctx.getPackageManager();PermissionInfo pi;pi = pm.getPermissionInfo(sigPermName, PackageManager.GET_META_DATA);String pkgname = pi.packageName;// Fail if the permission named sigPermName is not a Signature Permissionif (pi.protectionLevel != PermissionInfo.PROTECTION_SIGNATURE) return null;// Return the certificate hash value of the application which declares a permission named sigPermName.return PkgCert.hash(ctx, pkgname);} catch (NameNotFoundException e) {return null;}}
}

PkgCert.java

package org.jssec.android.shared;import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import android.content.Context;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.content.pm.PackageManager.NameNotFoundException;
import android.content.pm.Signature;public class PkgCert {public static boolean test(Context ctx, String pkgname, String correctHash) {if (correctHash == null) return false;correctHash = correctHash.replaceAll(" ", "");return correctHash.equals(hash(ctx, pkgname));}public static String hash(Context ctx, String pkgname) {if (pkgname == null) return null;try {PackageManager pm = ctx.getPackageManager();PackageInfo pkginfo = pm.getPackageInfo(pkgname, PackageManager.GET_SIGNATURES);if (pkginfo.signatures.length != 1) return null; // Will not handle multiple signatures.Signature sig = pkginfo.signatures[0];byte[] cert = sig.toByteArray();byte[] sha256 = computeSha256(cert);return byte2hex(sha256);} catch (NameNotFoundException e) {return null;}}private static byte[] computeSha256(byte[] data) {try {return MessageDigest.getInstance("SHA-256").digest(data);} catch (NoSuchAlgorithmException e) {return null;}}private static String byte2hex(byte[] data) {if (data == null) return null;final StringBuilder hexadecimal = new StringBuilder();for (final byte b : data) {hexadecimal.append(String.format("%02X", b));}return hexadecimal.toString();}
}

要点 9：导出 APK 时，请使用与目标应用相同的开发人员密钥对 APK 进行签名。

使用内部活动的代码如下：

要点（使用活动）：

10) 声明你要使用内部签名权限。

11) 确认内部签名权限是由内部应用定义的。

12) 验证目标应用是否使用内部证书签名。

13) 由于目标应用是内部的，所以敏感信息只能由putExtra()发送。

14) 使用显式意图调用内部活动。

15) 即使数据来自内部应用，也要小心并安全地处理接收到的数据。

16) 导出 APK 时，请使用与目标应用相同的开发人员密钥对 APK 进行签名。

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"package="org.jssec.android.activity.inhouseuser" ><!-- *** POINT 10 *** Declare to use the in-house signature permission --><uses-permission
    android:name="org.jssec.android.activity.inhouseactivity.MY_PERMISSION" /><application
        android:allowBackup="false"android:icon="@drawable/ic_launcher"android:label="@string/app_name" ><activity
            android:name="org.jssec.android.activity.inhouseuser.InhouseUserActivity"android:label="@string/app_name"android:exported="true" ><intent-filter><action android:name="android.intent.action.MAIN" /><category android:name="android.intent.category.LAUNCHER" /></intent-filter></activity></application>
</manifest>

InhouseUserActivity.java

package org.jssec.android.activity.inhouseuser;import org.jssec.android.shared.PkgCert;
import org.jssec.android.shared.SigPerm;
import org.jssec.android.shared.Utils;
import android.app.Activity;
import android.content.ActivityNotFoundException;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;public class InhouseUserActivity extends Activity {// Target Activity informationprivate static final String TARGET_PACKAGE = "org.jssec.android.activity.inhouseactivity";private static final String TARGET_ACTIVITY = "org.jssec.android.activity.inhouseactivity.InhouseActivity";// In-house Signature Permissionprivate static final String MY_PERMISSION = "org.jssec.android.activity.inhouseactivity.MY_PERMISSION";// In-house certificate hash valueprivate static String sMyCertHash = null;private static String myCertHash(Context context) {if (sMyCertHash == null) {if (Utils.isDebuggable(context)) {// Certificate hash value of "androiddebugkey" in the debug.keystore.sMyCertHash = "0EFB7236 328348A9 89718BAD DF57F544 D5CCB4AE B9DB34BC 1E29DD26 F77C8255";} else {// Certificate hash value of "my company key" in the keystore.sMyCertHash = "D397D343 A5CBC10F 4EDDEB7C A10062DE 5690984F 1FB9E88B D7B3A7C2 42E142CA";}}return sMyCertHash;}private static final int REQUEST_CODE = 1;@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);}public void onUseActivityClick(View view) {// *** POINT 11 *** Verify that the in-house signature permission is defined by an in-house application.if (!SigPerm.test(this, MY_PERMISSION, myCertHash(this))) {Toast.makeText(this, "The in-house signature permission is not declared by in-house application.",Toast.LENGTH_LONG).show();return;}// ** POINT 12 *** Verify that the destination application is signed with the in-house certificate.if (!PkgCert.test(this, TARGET_PACKAGE, myCertHash(this))) {Toast.makeText(this, "Target application is not an in-house application.", Toast.LENGTH_LONG).show();return;}try {Intent intent = new Intent();// *** POINT 13 *** Sensitive information can be sent only by putExtra() since the destination application is in-house.intent.putExtra("PARAM", "Sensitive Info");// *** POINT 14 *** Use explicit intents to call an In-house Activity.intent.setClassName(TARGET_PACKAGE, TARGET_ACTIVITY);startActivityForResult(intent, REQUEST_CODE);} catch (ActivityNotFoundException e) {Toast.makeText(this, "Target activity not found.", Toast.LENGTH_LONG).show();}}@Overridepublic void onActivityResult(int requestCode, int resultCode, Intent data) {super.onActivityResult(requestCode, resultCode, data);if (resultCode != RESULT_OK) return;switch (requestCode) {case REQUEST_CODE:String result = data.getStringExtra("RESULT");// *** POINT 15 *** Handle the received data carefully and securely,// even though the data came from an in-house application.// Omitted, since this is a sample. Please refer to "3.2 Handling Input Data Carefully and Securely."Toast.makeText(this, String.format("Received result: ¥"%s¥"", result), Toast.LENGTH_LONG).show();break;}}
}

SigPerm.java

package org.jssec.android.shared;import android.content.Context;
import android.content.pm.PackageManager;
import android.content.pm.PackageManager.NameNotFoundException;
import android.content.pm.PermissionInfo;public class SigPerm {public static boolean test(Context ctx, String sigPermName, String correctHash) {if (correctHash == null) return false;correctHash = correctHash.replaceAll(" ", "");return correctHash.equals(hash(ctx, sigPermName));}public static String hash(Context ctx, String sigPermName) {if (sigPermName == null) return null;try {// Get the package name of the application which declares a permission named sigPermName.PackageManager pm = ctx.getPackageManager();PermissionInfo pi;pi = pm.getPermissionInfo(sigPermName, PackageManager.GET_META_DATA);String pkgname = pi.packageName;// Fail if the permission named sigPermName is not a Signature Permissionif (pi.protectionLevel != PermissionInfo.PROTECTION_SIGNATURE) return null;// Return the certificate hash value of the application which declares a permission named sigPermName.return PkgCert.hash(ctx, pkgname);} catch (NameNotFoundException e) {return null;}}
}

PkgCert.java

package org.jssec.android.shared;import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import android.content.Context;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.content.pm.PackageManager.NameNotFoundException;
import android.content.pm.Signature;public class PkgCert {public static boolean test(Context ctx, String pkgname, String correctHash) {if (correctHash == null) return false;correctHash = correctHash.replaceAll(" ", "");return correctHash.equals(hash(ctx, pkgname));}public static String hash(Context ctx, String pkgname) {if (pkgname == null) return null;try {PackageManager pm = ctx.getPackageManager();PackageInfo pkginfo = pm.getPackageInfo(pkgname, PackageManager.GET_SIGNATURES);if (pkginfo.signatures.length != 1) return null; // Will not handle multiple signatures.Signature sig = pkginfo.signatures[0];byte[] cert = sig.toByteArray();byte[] sha256 = computeSha256(cert);return byte2hex(sha256);} catch (NameNotFoundException e) {return null;}}private static byte[] computeSha256(byte[] data) {try {return MessageDigest.getInstance("SHA-256").digest(data);} catch (NoSuchAlgorithmException e) {return null;}}private static String byte2hex(byte[] data) {if (data == null) return null;final StringBuilder hexadecimal = new StringBuilder();for (final byte b : data) {hexadecimal.append(String.format("%02X", b));}return hexadecimal.toString();}
}

要点 16：导出 APK 时，请使用与目标应用相同的开发人员密钥对 APK 进行签名。