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Les permissions sous Android

  1. Les différents types de permissions
  2. Demande de permission
  3. Création de permissions nouvelles (utile pour un ContentProvider)
  4. Protection d'un composant par une permission
  5. Permissions temporaires pour l'accès aux données
  6. Révocation de permissions
  7. Coopération malveillante inter-applicative

Les différents types de permissions

Demande de permission

Un composant nécessitant une permission la demande dans le manifeste de l'application : <uses-permission android:name="nom.de.la.permission" /> :

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="fr.upem.coursand">

    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.CAMERA" />
    <uses-permission android:name="android.permission.FLASHLIGHT" />
    <uses-permission android:name="android.permission.VIBRATE" />
    <uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
    <uses-permission android:name="android.permission.SEND_SMS" />
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
    <uses-permission android:name="android.permission.RECORD_AUDIO" />
    <uses-permission android:name="android.permission.READ_CONTACTS" />
    <uses-permission android:name="android.permission.READ_CALL_LOG" />
    <uses-permission android:name="android.permission.READ_SMS" />
    <uses-permission android:name="android.permission.READ_CALENDAR" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        
        <!-- ... -->
        
    </application>

</manifest>

Exemple de code pour une activité nécessitant une permission dangereuse :

package fr.upem.coursand.permission;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.pm.PackageManager;
import android.os.Bundle;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;

import java.util.HashMap;
import java.util.Map;

/** Template for an activity that needs to acquire a dangerous permission */
public class RequiringPermissionActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
    }

    /** Store here the permission requests with the associated onSuccess and onFailure runnables */
    private Map<Integer, Runnable[]> permissionRequests = new HashMap<>();
    private int nextPermissionRequestCode = 1;

    /** Run code that requires a prior permission grant 
     *  @param permissionName name of the permission to claim
     *  @param rationale message to display to explain to the user why this permission must be used 
     * 	@param onFailure code to execute if the permission is refused
     *  @param onSuccess code to execute if the permission is granted 
     */
    protected void runWithPermission(String permissionName, String rationale, Runnable onFailure, Runnable onSuccess)
    {
		// Is the permission already granted?
        if (ContextCompat.checkSelfPermission(this, permissionName) != PackageManager.PERMISSION_GRANTED)
        {
			// The permission is not granted yet
            // Should we show an explanation?
            if (rationale != null && ActivityCompat.shouldShowRequestPermissionRationale(this, permissionName))
            {
                // show an explanation with a dialog
                AlertDialog alertDialog = new AlertDialog.Builder(this).create();
                alertDialog.setTitle("Permission information");
                alertDialog.setMessage(rationale);
                alertDialog.setIcon(android.R.drawable.ic_dialog_info);
                // if ok is pressed rerun the method (but not showing now the rationale)
                alertDialog.setButton("OK", ((dialogInterface, i) -> runWithPermission(permissionName, null, onFailure, onSuccess)));
                alertDialog.show();
            } else
            {
                int code = nextPermissionRequestCode++; // use an unique id for the permission request
                permissionRequests.put(code, new Runnable[]{onFailure, onSuccess});
                // request asynchronously the permission
                ActivityCompat.requestPermissions(this, new String[]{permissionName}, code);
            }
        } else
            onSuccess.run(); // the permission has already been given already given
    }

	/** This method is called when the user has answered to the permission request */
    @Override
    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults)
    {
        Runnable[] runnables = permissionRequests.get(requestCode);
        if (runnables != null)
        {
            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED)
                runnables[1].run(); // run onSuccess since the permission has been granted
            else
                runnables[0].run(); // permission not granted
        }
    }
}

Création de permissions nouvelles (utile pour un ContentProvider)

Voici un exemple pour donner l'accès en lecture/écriture à un ContentProvider :

 <permission android:name="fr.upemlv.gpslog.GPS_TRACE_READ"
        android:label="@string/perm_label_GPSTraceRead"
        android:description="@string/perm_desc_GPSTraceRead"
        android:permissionGroup="android.permission-group.PESONAL_INFO"
        android:protectionLevel="dangerous" />

 <permission android:name="fr.upemlv.gpslog.GPS_TRACE_WRITE"
        android:label="@string/perm_label_GPSTraceWrite"
        android:description="@string/perm_desc_GPSTraceWrite"
        android:permissionGroup="android.permission-group.PESONAL_INFO"
        android:protectionLevel="dangerous" />

Remarque : pour être accessible d'une autre application, le ContentProvider
doit également posséder la propriété android:exported="true"

Protection d'un composant par une permission

<provider ...>
	<path-permission android:path="string"
                 android:pathPrefix="string"
                 android:pathPattern="string"
                 android:permission="string"
                 android:readPermission="string"
                 android:writePermission="string" />
</provider>

Permissions temporaires pour l'accès aux données

Transmission d'Intent avec permission temporaire d'accès :

Uri uri = Uri.parse("content://fr.upemlv.gpslogger.provider/log/" + id);
Intent intent = new Intent();
intent.setAction(MAP_VIEW);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
intent.setData(uri);
startActivity(intent) ;

Accord/révocation de permissions (méthodes de Context) :

public void grantUriPermission(String toPackage, Uri uri, int modeFlags)
public void revokeUriPermission(Uri uri, int modeFlags)

Révocation de permissions

Coopération malveillante inter-applicative