Restrict interactions with other apps

Permissions aren't only for requesting system functionality. You can also restrict how other apps can interact with your app's components.

This guide explains how to view the set of permissions that another app has declared. The guide also explains how you can configure activities, services, content providers, and broadcast receivers to restrict how other apps can interact with your app. Finally, this page provides guidance on several other ways of enforcing patterns of interaction between apps.

View another app's permissions

To view the set of permissions that another app declares, use a device or emulator to complete the following steps:

1. Open an app's App info screen.

2. Select Permissions. The App permissions screen loads.

   This screen shows a set of permission groups. The system organizes the set of permissions that an app has declared into these groups.

Restrict interactions with your app's activities

Permissions applied using the android:permission attribute to the <activity> tag in the manifest restrict who can start that Activity. The permission is checked during Context.startActivity() and Activity.startActivityForResult(). If the caller doesn't have the required permission, then a SecurityException occurs.

Restrict interactions with your app's services

Permissions applied using the android:permission attribute to the <service> tag in the manifest restrict who can start or bind to the associated Service. The permission is checked during Context.startService(), Context.stopService() and Context.bindService(). If the caller doesn't have the required permission, then a SecurityException occurs.

Restrict interactions with your app's content providers

Permissions applied using the android:permission attribute to the <provider> tag restrict who can access the data in a ContentProvider. (Content providers have an important additional security facility available to them called URI permissions which is described next.) Unlike the other components, there are two separate permission attributes you can set: android:readPermission restricts who can read from the provider, and android:writePermission restricts who can write to it. Note that if a provider is protected with both a read and write permission, holding only the write permission doesn't mean you can read from a provider.

The permissions are checked when you first retrieve a provider (if you don't have either permission, a SecurityException occurs), and as you perform operations on the provider. Using ContentResolver.query() requires holding the read permission; using ContentResolver.insert(), ContentResolver.update(), or ContentResolver.delete() requires the write permission. In all of these cases, not holding the required permission results in a SecurityException.

Allow access on a per-URI basis

The system provides you with additional fine-grained control on how other apps can access your app's content providers. In particular, your content provider can protect itself with read and write permissions while still allowing the provider's direct clients to share specific URIs with other apps. To declare your app's support for this model, use the android:grantUriPermissions attribute or the <grant-uri-permission element.

You can also grant permissions on a per-URI basis. When starting an activity or returning a result to an activity, set the Intent.FLAG_GRANT_READ_URI_PERMISSION, intent flag, the Intent.FLAG_GRANT_WRITE_URI_PERMISSION, intent flag, or both flags. This gives another app read, write, and read/write permissions, respectively, for the data URI that's included in the intent. The other app gains these permissions for the specific URI regardless of whether it has permission to access data in the content provider more generally.

For example, suppose that a user is viewing an email in your app, and this email includes an image as an attachment. Other apps shouldn't be able to access the email contents in general, but they might be interested in viewing the image. Your app can use an intent and the Intent.FLAG_GRANT_READ_URI_PERMISSION intent flag in order for an image-viewing app to view the image.

Another consideration is app visibility. If your app targets Android 11 (API level 30) or higher, the system makes some apps visible to your app automatically, but it hides other apps by default. If your app has a content provider and has granted URI permissions to another app, your app is automatically visible to the other app.

For more information, view the reference material for the grantUriPermission(), revokeUriPermission(), and checkUriPermission() methods.

Restrict interactions with your app's broadcast receivers

Permissions applied using the android:permission attribute to the <receiver> tag restrict who can send broadcasts to the associated BroadcastReceiver. The permission is checked after Context.sendBroadcast() returns, as the system tries to deliver the submitted broadcast to the given receiver. As a result, a permission failure doesn't result in an exception being thrown back to the caller; it just doesn't deliver the Intent.

In the same way, a permission can be supplied to Context.registerReceiver() to control who can broadcast to a programmatically registered receiver. Going the other way, a permission can be supplied when calling Context.sendBroadcast() to restrict which broadcast receivers are allowed to receive the broadcast.

Note that both a receiver and a broadcaster can require a permission. When this happens, both permission checks must pass for the intent to be delivered to the associated target. For more information, see Restricting broadcasts with permissions.

Other checks for permissions

There are a number of other useful ways to check permissions:

• During a call into a service, pass a permission string into Context.checkCallingPermission(). This method returns an integer that indicates whether that permission has been granted to the current calling process. Note that this can only be used when you are executing a call coming in from another process, usually through an IDL interface published from a service or in some other way given to another process.
• To check whether another process has been granted a particular permission, pass the process (PID) into Context.checkPermission().
• To check whether another package has been granted a particular permission, pass the package name into PackageManager.checkPermission().