Device administration overview

Device admin deprecation. Starting with Android 9 (API level 28), some admin policies will be marked as deprecated when invoked by a device admin. We recommend you start to prepare now for this change. To learn more and see the migration options, read Device admin deprecation.

Android includes support for enterprise apps by offering the Android Device Administration API. The Device Administration API provides device administration features at the system level. These APIs allow you to create security-aware apps that are useful in enterprise settings, in which IT professionals require rich control over employee devices. For example, the built-in Android Email app has leveraged these APIs to improve Exchange support. Through the Email app, Exchange administrators can enforce password policies — including alphanumeric passwords or numeric PINs — across devices. Administrators can also remotely wipe (that is, restore factory defaults on) lost or stolen handsets. Exchange users can sync their email and calendar data.

This document is intended for developers who want to develop enterprise solutions for Android-powered devices. It discusses the various features provided by the Device Administration API to provide stronger security for employee devices that are powered by Android.

Note For information on building a Work Policy Controller for Android for Work deployments, see Build a Device Policy Controller.

Device administration API overview

Here are examples of the types of apps that might use the Device Administration API:

• Email clients.
• Security apps that do remote wipe.
• Device management services and apps.

How does it work?

You use the Device Administration API to write device admin apps that users install on their devices. The device admin app enforces the desired policies. Here's how it works:

• A system administrator writes a device admin app that enforces remote/local device security policies. These policies could be hard-coded into the app, or the app could dynamically fetch policies from a third-party server.
• The app is installed on users' devices. Android does not currently have an automated provisioning solution. Some of the ways a sysadmin might distribute the app to users are as follows:
  • Google Play.
  • Enabling installation from another store.
  • Distributing the app through other means, such as email or websites.
• The system prompts the user to enable the device admin app. How and when this happens depends on how the app is implemented.
• Once users enable the device admin app, they are subject to its policies. Complying with those policies typically confers benefits, such as access to sensitive systems and data.

If users do not enable the device admin app, it remains on the device, but in an inactive state. Users will not be subject to its policies, and they will conversely not get any of the app's benefits—for example, they may not be able to sync data.

If a user fails to comply with the policies (for example, if a user sets a password that violates the guidelines), it is up to the app to decide how to handle this. However, typically this will result in the user not being able to sync data.

If a device attempts to connect to a server that requires policies not supported in the Device Administration API, the connection will not be allowed. The Device Administration API does not currently allow partial provisioning. In other words, if a device (for example, a legacy device) does not support all of the stated policies, there is no way to allow the device to connect.

If a device contains multiple enabled admin apps, the strictest policy is enforced. There is no way to target a particular admin app.

To uninstall an existing device admin app, users need to first unregister the app as an administrator.

Policies

In an enterprise setting, it's often the case that employee devices must adhere to a strict set of policies that govern the use of the device. The Device Administration API supports the policies listed in Table 1. Note that the Device Administration API currently only supports passwords for screen lock:

Table 1. Policies supported by the Device Administration API.

Other features

In addition to supporting the policies listed in the above table, the Device Administration API lets you do the following:

• Prompt user to set a new password.
• Lock device immediately.
• Wipe the device's data (that is, restore the device to its factory defaults).

Sample app

The examples used in this document are based on the Device Administration API sample, which is included in the SDK samples (available through the Android SDK Manager) and located on your system as <sdk_root>/ApiDemos/app/src/main/java/com/example/android/apis/app/DeviceAdminSample.java.

The sample app offers a demo of device admin features. It presents users with a user interface that lets them enable the device admin app. Once they've enabled the app, they can use the buttons in the user interface to do the following:

• Set password quality.
• Specify requirements for the user's password, such as minimum length, the minimum number of numeric characters it must contain, and so on.
• Set the password. If the password does not conform to the specified policies, the system returns an error.
• Set how many failed password attempts can occur before the device is wiped (that is, restored to factory settings).
• Set how long from now the password will expire.
• Set the password history length (length refers to number of old passwords stored in the history). This prevents users from reusing one of the last n passwords they previously used.
• Specify that the storage area should be encrypted, if the device supports it.
• Set the maximum amount of inactive time that can elapse before the device locks.
• Make the device lock immediately.
• Wipe the device's data (that is, restore factory settings).
• Disable the camera.

Figure 1. Screenshot of the sample app

Developing a device administration app

System administrators can use the Device Administration API to write an app that enforces remote/local device security policy enforcement. This section summarizes the steps involved in creating a device administration app.

Creating the manifest

To use the Device Administration API, the app's manifest must include the following:

• A subclass of DeviceAdminReceiver that includes the following:
  • The BIND_DEVICE_ADMIN permission.
  • The ability to respond to the ACTION_DEVICE_ADMIN_ENABLED intent, expressed in the manifest as an intent filter.
• A declaration of security policies used in metadata.

Here is an excerpt from the Device Administration sample manifest:

<activity android:name=".app.DeviceAdminSample"
            android:label="@string/activity_sample_device_admin">
    <intent-filter>
        <action android:name="android.intent.action.MAIN" />
        <category android:name="android.intent.category.SAMPLE_CODE" />
    </intent-filter>
</activity>
<receiver android:name=".app.DeviceAdminSample$DeviceAdminSampleReceiver"
        android:label="@string/sample_device_admin"
        android:description="@string/sample_device_admin_description"
        android:permission="android.permission.BIND_DEVICE_ADMIN">
    <meta-data android:name="android.app.device_admin"
            android:resource="@xml/device_admin_sample" />
    <intent-filter>
        <action android:name="android.app.action.DEVICE_ADMIN_ENABLED" />
    </intent-filter>
</receiver>

Note that:

• The following attributes refer to string resources that for the sample app reside in ApiDemos/res/values/strings.xml. For more information about resources, see Application Resources.
  • android:label="@string/activity_sample_device_admin" refers to the user-readable label for the activity.
  • android:label="@string/sample_device_admin" refers to the user-readable label for the permission.
  • android:description="@string/sample_device_admin_description" refers to the user-readable description of the permission. A descripton is typically longer and more informative than a label.
• android:permission="android.permission.BIND_DEVICE_ADMIN" is a permission that a DeviceAdminReceiver subclass must have, to ensure that only the system can interact with the receiver (no app can be granted this permission). This prevents other apps from abusing your device admin app.
• android.app.action.DEVICE_ADMIN_ENABLED is the primary action that a DeviceAdminReceiver subclass must handle to be allowed to manage a device. This is set to the receiver when the user enables the device admin app. Your code typically handles this in onEnabled(). To be supported, the receiver must also require the BIND_DEVICE_ADMIN permission so that other apps cannot abuse it.
• When a user enables the device admin app, that gives the receiver permission to perform actions in response to the broadcast of particular system events. When suitable event arises, the app can impose a policy. For example, if the user attempts to set a new password that doesn't meet the policy requirements, the app can prompt the user to pick a different password that does meet the requirements.
• Avoid changing the receiver name after publishing your app. If the name in the manifest changes, device admin is disabled when users update the app. To learn more, see <receiver>.
• android:resource="@xml/device_admin_sample" declares the security policies used in metadata. The metadata provides additional information specific to the device administrator, as parsed by the DeviceAdminInfo class. Here are the contents of device_admin_sample.xml:

<device-admin xmlns:android="http://schemas.android.com/apk/res/android">
  <uses-policies>
    <limit-password />
    <watch-login />
    <reset-password />
    <force-lock />
    <wipe-data />
    <expire-password />
    <encrypted-storage />
    <disable-camera />
  </uses-policies>
</device-admin>

When designing your device administration app, you don't need to include all of the policies, just the ones that are relevant for your app.

Implementing the code

The Device Administration API includes the following classes:

DeviceAdminReceiver

Base class for implementing a device administration component. This class provides a convenience for interpreting the raw intent actions that are sent by the system. Your Device Administration app must include a DeviceAdminReceiver subclass.

DevicePolicyManager

A class for managing policies enforced on a device. Most clients of this class must have published a DeviceAdminReceiver that the user has currently enabled. The DevicePolicyManager manages policies for one or more DeviceAdminReceiver instances

DeviceAdminInfo

This class is used to specify metadata for a device administrator component.

These classes provide the foundation for a fully functional device administration app. The rest of this section describes how you use the DeviceAdminReceiver and DevicePolicyManager APIs to write a device admin app.

Subclassing DeviceAdminReceiver

To create a device admin app, you must subclass DeviceAdminReceiver. The DeviceAdminReceiver class consists of a series of callbacks that are triggered when particular events occur.

In its DeviceAdminReceiver subclass, the sample app simply displays a Toast notification in response to particular events. For example:

class DeviceAdminSample : DeviceAdminReceiver() {

    private fun showToast(context: Context, msg: String) {
        context.getString(R.string.admin_receiver_status, msg).let { status ->
            Toast.makeText(context, status, Toast.LENGTH_SHORT).show()
        }
    }

    override fun onEnabled(context: Context, intent: Intent) =
            showToast(context, context.getString(R.string.admin_receiver_status_enabled))

    override fun onDisableRequested(context: Context, intent: Intent): CharSequence =
            context.getString(R.string.admin_receiver_status_disable_warning)

    override fun onDisabled(context: Context, intent: Intent) =
            showToast(context, context.getString(R.string.admin_receiver_status_disabled))

    override fun onPasswordChanged(context: Context, intent: Intent, userHandle: UserHandle) =
            showToast(context, context.getString(R.string.admin_receiver_status_pw_changed))
...
}

public class DeviceAdminSample extends DeviceAdminReceiver {

    void showToast(Context context, String msg) {
        String status = context.getString(R.string.admin_receiver_status, msg);
        Toast.makeText(context, status, Toast.LENGTH_SHORT).show();
    }

    @Override
    public void onEnabled(Context context, Intent intent) {
        showToast(context, context.getString(R.string.admin_receiver_status_enabled));
    }

    @Override
    public CharSequence onDisableRequested(Context context, Intent intent) {
        return context.getString(R.string.admin_receiver_status_disable_warning);
    }

    @Override
    public void onDisabled(Context context, Intent intent) {
        showToast(context, context.getString(R.string.admin_receiver_status_disabled));
    }

    @Override
    public void onPasswordChanged(Context context, Intent intent, UserHandle userHandle) {
        showToast(context, context.getString(R.string.admin_receiver_status_pw_changed));
    }
...
}

Enabling the app

One of the major events a device admin app has to handle is the user enabling the app. The user must explicitly enable the app for the policies to be enforced. If the user chooses not to enable the app it will still be present on the device, but its policies will not be enforced, and the user will not get any of the app's benefits.

The process of enabling the app begins when the user performs an action that triggers the ACTION_ADD_DEVICE_ADMIN intent. In the sample app, this happens when the user clicks the Enable Admin checkbox.

When the user clicks the Enable Admin checkbox, the display changes to prompt the user to activate the device admin app, as shown in figure 2.

Figure 2. Sample app: activating the app

Below is the code that gets executed when the user clicks the Enable Admin checkbox. This has the effect of triggering the onPreferenceChange() callback. This callback is invoked when the value of this Preference has been changed by the user and is about to be set and/or persisted. If the user is enabling the app, the display changes to prompt the user to activate the device admin app, as shown in figure 2. Otherwise, the device admin app is disabled.

override fun onPreferenceChange(preference: Preference, newValue: Any): Boolean {
    if (super.onPreferenceChange(preference, newValue)) return true
    val value = newValue as Boolean
    if (preference == enableCheckbox) {
        if (value != adminActive) {
            if (value) {
                // Launch the activity to have the user enable our admin.
                val intent = Intent(DevicePolicyManager.ACTION_ADD_DEVICE_ADMIN).apply {
                    putExtra(DevicePolicyManager.EXTRA_DEVICE_ADMIN, deviceAdminSample)
                    putExtra(DevicePolicyManager.EXTRA_ADD_EXPLANATION,
                            activity.getString(R.string.add_admin_extra_app_text))
                }
                startActivityForResult(intent, REQUEST_CODE_ENABLE_ADMIN)
                // return false - don't update checkbox until we're really active
                return false
            } else {
                dpm.removeActiveAdmin(deviceAdminSample)
                enableDeviceCapabilitiesArea(false)
                adminActive = false
            }
        }
    } else if (preference == disableCameraCheckbox) {
        dpm.setCameraDisabled(deviceAdminSample, value)
    }
    return true
}

@Override
public boolean onPreferenceChange(Preference preference, Object newValue) {
    if (super.onPreferenceChange(preference, newValue)) {
        return true;
    }
    boolean value = (Boolean) newValue;
    if (preference == enableCheckbox) {
        if (value != adminActive) {
            if (value) {
                // Launch the activity to have the user enable our admin.
                Intent intent = new Intent(DevicePolicyManager.ACTION_ADD_DEVICE_ADMIN);
                intent.putExtra(DevicePolicyManager.EXTRA_DEVICE_ADMIN, deviceAdminSample);
                intent.putExtra(DevicePolicyManager.EXTRA_ADD_EXPLANATION,
                        activity.getString(R.string.add_admin_extra_app_text));
                startActivityForResult(intent, REQUEST_CODE_ENABLE_ADMIN);
                // return false - don't update checkbox until we're really active
                return false;
            } else {
                dpm.removeActiveAdmin(deviceAdminSample);
                enableDeviceCapabilitiesArea(false);
                adminActive = false;
            }
        }
    } else if (preference == disableCameraCheckbox) {
        dpm.setCameraDisabled(deviceAdminSample, value);
    }
    return true;
}

The line intent.putExtra(DevicePolicyManager.EXTRA_DEVICE_ADMIN, mDeviceAdminSample) states that mDeviceAdminSample (which is a DeviceAdminReceiver component) is the target policy. This line invokes the user interface shown in figure 2, which guides users through adding the device administrator to the system (or allows them to reject it).

When the app needs to perform an operation that is contingent on the device admin app being enabled, it confirms that the app is active. To do this it uses the DevicePolicyManager method isAdminActive(). Notice that the DevicePolicyManager method isAdminActive() takes a DeviceAdminReceiver component as its argument:

private lateinit var dpm: DevicePolicyManager
...
private fun isActiveAdmin(): Boolean = dpm.isAdminActive(deviceAdminSample)

DevicePolicyManager dpm;
...
private boolean isActiveAdmin() {
    return dpm.isAdminActive(deviceAdminSample);
}

Managing policies

DevicePolicyManager is a public class for managing policies enforced on a device. DevicePolicyManager manages policies for one or more DeviceAdminReceiver instances.

You get a handle to the DevicePolicyManager as follows:

dpm = getSystemService(Context.DEVICE_POLICY_SERVICE) as DevicePolicyManager

DevicePolicyManager dpm =
    (DevicePolicyManager)getSystemService(Context.DEVICE_POLICY_SERVICE);

This section describes how to use DevicePolicyManager to perform administrative tasks:

• Set password policies
• Set device lock
• Perform data wipe

Set password policies

DevicePolicyManager includes APIs for setting and enforcing the device password policy. In the Device Administration API, the password only applies to screen lock. This section describes common password-related tasks.

Set a password for the device

This code displays a user interface prompting the user to set a password:

Intent(DevicePolicyManager.ACTION_SET_NEW_PASSWORD).also { intent ->
    startActivity(intent)
}

Intent intent = new Intent(DevicePolicyManager.ACTION_SET_NEW_PASSWORD);
startActivity(intent);

Set the password quality

The password quality can be one of the following DevicePolicyManager constants:

PASSWORD_QUALITY_ALPHABETIC

The user must enter a password containing at least alphabetic (or other symbol) characters.

PASSWORD_QUALITY_ALPHANUMERIC

The user must enter a password containing at least both numeric and alphabetic (or other symbol) characters.

PASSWORD_QUALITY_NUMERIC

The user must enter a password containing at least numeric characters.

PASSWORD_QUALITY_COMPLEX

The user must have entered a password containing at least a letter, a numerical digit and a special symbol.

PASSWORD_QUALITY_SOMETHING

The policy requires some kind of password, but doesn't care what it is.

PASSWORD_QUALITY_UNSPECIFIED

The policy has no requirements for the password.

For example, this is how you would set the password policy to require an alphanumeric password:

private lateinit var dpm: DevicePolicyManager
private lateinit var deviceAdminSample: ComponentName
...
dpm.setPasswordQuality(deviceAdminSample, DevicePolicyManager.PASSWORD_QUALITY_ALPHANUMERIC)

DevicePolicyManager dpm;
ComponentName deviceAdminSample;
...
dpm.setPasswordQuality(deviceAdminSample, DevicePolicyManager.PASSWORD_QUALITY_ALPHANUMERIC);

Set password content requirements

Beginning with Android 3.0, the DevicePolicyManager class includes methods that let you fine-tune the contents of the password. For example, you could set a policy that states that passwords must contain at least n uppercase letters. Here are the methods for fine-tuning a password's contents:

• setPasswordMinimumLetters()
• setPasswordMinimumLowerCase()
• setPasswordMinimumUpperCase()
• setPasswordMinimumNonLetter()
• setPasswordMinimumNumeric()
• setPasswordMinimumSymbols()

For example, this snippet states that the password must have at least 2 uppercase letters:

private lateinit var dpm: DevicePolicyManager
private lateinit var deviceAdminSample: ComponentName
private val pwMinUppercase = 2
...
dpm.setPasswordMinimumUpperCase(deviceAdminSample, pwMinUppercase)

DevicePolicyManager dpm;
ComponentName deviceAdminSample;
int pwMinUppercase = 2;
...
dpm.setPasswordMinimumUpperCase(deviceAdminSample, pwMinUppercase);

Set the minimum password length

You can specify that a password must be at least the specified minimum length. For example:

private lateinit var dpm: DevicePolicyManager
private lateinit var deviceAdminSample: ComponentName
private val pwLength: Int = ...
...
dpm.setPasswordMinimumLength(deviceAdminSample, pwLength)

DevicePolicyManager dpm;
ComponentName deviceAdminSample;
int pwLength;
...
dpm.setPasswordMinimumLength(deviceAdminSample, pwLength);

Set maximum failed password attempts

You can set the maximum number of allowed failed password attempts before the device is wiped (that is, reset to factory settings). For example:

val dPM:DevicePolicyManager
private lateinit var dpm: DevicePolicyManager
private lateinit var deviceAdminSample: ComponentName
private val maxFailedPw: Int = ...
...
dpm.setMaximumFailedPasswordsForWipe(deviceAdminSample, maxFailedPw)

DevicePolicyManager dpm;
ComponentName deviceAdminSample;
int maxFailedPw;
 ...
dpm.setMaximumFailedPasswordsForWipe(deviceAdminSample, maxFailedPw);

Set password expiration timeout

Beginning with Android 3.0, you can use the setPasswordExpirationTimeout() method to set when a password will expire, expressed as a delta in milliseconds from when a device admin sets the expiration timeout. For example:

private lateinit var dpm: DevicePolicyManager
private lateinit var deviceAdminSample: ComponentName
private val pwExpiration: Long = ...
...
dpm.setPasswordExpirationTimeout(deviceAdminSample, pwExpiration)

DevicePolicyManager dpm;
ComponentName deviceAdminSample;
long pwExpiration;
...
dpm.setPasswordExpirationTimeout(deviceAdminSample, pwExpiration);

Restrict password based on history

Beginning with Android 3.0, you can use the setPasswordHistoryLength() method to limit users' ability to reuse old passwords. This method takes a length parameter, which specifies how many old passwords are stored. When this policy is active, users cannot enter a new password that matches the last n passwords. This prevents users from using the same password over and over. This policy is typically used in conjunction with setPasswordExpirationTimeout(), which forces users to update their passwords after a specified amount of time has elapsed.

For example, this snippet prohibits users from reusing any of their last 5 passwords:

private lateinit var dpm: DevicePolicyManager
private lateinit var deviceAdminSample: ComponentName
private val pwHistoryLength = 5
...
dpm.setPasswordHistoryLength(deviceAdminSample, pwHistoryLength)

DevicePolicyManager dpm;
ComponentName deviceAdminSample;
int pwHistoryLength = 5;
...
dpm.setPasswordHistoryLength(deviceAdminSample, pwHistoryLength);

Set device lock

You can set the maximum period of user inactivity that can occur before the device locks. For example:

private lateinit var dpm: DevicePolicyManager
private lateinit var deviceAdminSample: ComponentName
private val timeMs: Long = 1000L * timeout.text.toString().toLong()
...
dpm.setMaximumTimeToLock(deviceAdminSample, timeMs)

DevicePolicyManager dpm;
ComponentName deviceAdminSample;
...
long timeMs = 1000L*Long.parseLong(timeout.getText().toString());
dpm.setMaximumTimeToLock(deviceAdminSample, timeMs);

You can also programmatically tell the device to lock immediately:

private lateinit var dpm: DevicePolicyManager
dpm.lockNow()

DevicePolicyManager dpm;
dpm.lockNow();

Perform data wipe

You can use the DevicePolicyManager method wipeData() to reset the device to factory settings. This is useful if the device is lost or stolen. Often the decision to wipe the device is the result of certain conditions being met. For example, you can use setMaximumFailedPasswordsForWipe() to state that a device should be wiped after a specific number of failed password attempts.

You wipe data as follows:

private lateinit var dpm: DevicePolicyManager
dpm.wipeData(0)

DevicePolicyManager dpm;
dpm.wipeData(0);

The wipeData() method takes as its parameter a bit mask of additional options. Currently the value must be 0.

Disable camera

Beginning with Android 4.0, you can disable the camera. Note that this doesn't have to be a permanent disabling. The camera can be enabled/disabled dynamically based on context, time, and so on.

You control whether the camera is disabled by using the setCameraDisabled() method. For example, this snippet sets the camera to be enabled or disabled based on a checkbox setting:

private lateinit var disableCameraCheckbox: CheckBoxPreference
private lateinit var dpm: DevicePolicyManager
private lateinit var deviceAdminSample: ComponentName
...
dpm.setCameraDisabled(deviceAdminSample, mDisableCameraCheckbox.isChecked)

private CheckBoxPreference disableCameraCheckbox;
DevicePolicyManager dpm;
ComponentName deviceAdminSample;
...
dpm.setCameraDisabled(deviceAdminSample, mDisableCameraCheckbox.isChecked());

Storage encryption

Beginning with Android 3.0, you can use the setStorageEncryption() method to set a policy requiring encryption of the storage area, where supported.

For example:

private lateinit var dpm: DevicePolicyManager
private lateinit var deviceAdminSample: ComponentName
...
dpm.setStorageEncryption(deviceAdminSample, true)

DevicePolicyManager dpm;
ComponentName deviceAdminSample;
...
dpm.setStorageEncryption(deviceAdminSample, true);

See the Device Administration API sample for a complete example of how to enable storage encryption.

Additional code samples

The Android AppRestrictionEnforcer and DeviceOwner samples further demonstrate the use of the APIs covered on this page.