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Commit d3773546 authored by Bram Bonné's avatar Bram Bonné
Browse files

Update storage permission policy to use AppCompat APIs. 

This CL introduces ENABLE_SCOPED_STORAGE and REQUIRE_SCOPED_STORAGE as
AppCompat changes that are enabled for apps with targetSDK > P and apps
with targetSDK > Q respectively.

This change removes the getMinimumTargetSDK method, as it
is no longer needed.

Change-Id: I6b05252d42d3b2f1030928ffd03c02523c5a01d2
Fix: 147034231
Bug: 144914977
Bug: 131432978
Test: atest RestrictedPermissionsTest
Test: atest RestrictedStoragePermissionSharedUidTest
parent 6a1e0b72

services/core/java/com/android/server/policy/SoftRestrictedPermissionPolicy.java

+105 −49
Original line number Diff line number Diff line
@@ -27,16 +27,22 @@ import static android.content.pm.PackageManager.FLAG_PERMISSION_RESTRICTION_SYST 
import static android.content.pm.PackageManager.FLAG_PERMISSION_RESTRICTION_UPGRADE_EXEMPT;

import static android.content.pm.PackageManager.PERMISSION_GRANTED;



import static java.lang.Integer.min;



import android.annotation.NonNull;

import android.annotation.Nullable;

import android.app.AppOpsManager;

import android.compat.annotation.ChangeId;

import android.compat.annotation.EnabledAfter;

import android.content.Context;

import android.content.pm.ApplicationInfo;

import android.content.pm.PackageManager;

import android.os.Build;

import android.os.Binder;

import android.os.IBinder;

import android.os.RemoteException;

import android.os.ServiceManager;

import android.os.UserHandle;

import android.util.Log;



import com.android.internal.compat.IPlatformCompat;



/**

 * The behavior of soft restricted permissions is different for each permission. This class collects
@@ -46,6 +52,27 @@ import android.os.UserHandle; 
 * {@link com.android.packageinstaller.permission.utils.SoftRestrictedPermissionPolicy}

 */

public abstract class SoftRestrictedPermissionPolicy {

    /**

     * Enables scoped storage, with exceptions for apps that explicitly request legacy access, or

     * apps that hold the {@code android.Manifest.permission#WRITE_MEDIA_STORAGE} permission.

     * See https://developer.android.com/training/data-storage#scoped-storage for more information.

     */

    @ChangeId

    // This change is enabled for apps with targetSDK > {@link android.os.Build.VERSION_CODES.P}

    @EnabledAfter(targetSdkVersion = android.os.Build.VERSION_CODES.P)

    static final long ENABLE_SCOPED_STORAGE = 144914977L;



    /**

     * Enforces scoped storage for all apps, preventing individual apps from opting out. This change

     * has precedence over {@code ENABLE_SCOPED_STORAGE}.

     */

    @ChangeId

    // This change is enabled for apps with targetSDK > {@link android.os.Build.VERSION_CODES.Q}.

    @EnabledAfter(targetSdkVersion = android.os.Build.VERSION_CODES.Q)

    static final long REQUIRE_SCOPED_STORAGE = 131432978L;



    private static final String LOG_TAG = SoftRestrictedPermissionPolicy.class.getSimpleName();



    private static final int FLAGS_PERMISSION_RESTRICTION_ANY_EXEMPT =

            FLAG_PERMISSION_RESTRICTION_SYSTEM_EXEMPT

                    | FLAG_PERMISSION_RESTRICTION_UPGRADE_EXEMPT
@@ -59,41 +86,6 @@ public abstract class SoftRestrictedPermissionPolicy { 
                }

            };



    /**

     * TargetSDK is per package. To make sure two apps int the same shared UID do not fight over

     * what to set, always compute the combined targetSDK.

     *

     * @param context A context

     * @param appInfo The app that is changed

     * @param user The user the app belongs to

     *

     * @return The minimum targetSDK of all apps sharing the uid of the app

     */

    private static int getMinimumTargetSDK(@NonNull Context context,

            @NonNull ApplicationInfo appInfo, @NonNull UserHandle user) {

        PackageManager pm = context.getPackageManager();



        int minimumTargetSDK = appInfo.targetSdkVersion;



        String[] uidPkgs = pm.getPackagesForUid(appInfo.uid);

        if (uidPkgs != null) {

            for (String uidPkg : uidPkgs) {

                if (!uidPkg.equals(appInfo.packageName)) {

                    ApplicationInfo uidPkgInfo;

                    try {

                        uidPkgInfo = pm.getApplicationInfoAsUser(uidPkg, 0, user);

                    } catch (PackageManager.NameNotFoundException e) {

                        continue;

                    }



                    minimumTargetSDK = min(minimumTargetSDK, uidPkgInfo.targetSdkVersion);

                }

            }

        }



        return minimumTargetSDK;

    }



    /**

     * Get the policy for a soft restricted permission.

     *
@@ -114,27 +106,31 @@ public abstract class SoftRestrictedPermissionPolicy { 
            case READ_EXTERNAL_STORAGE: {

                final boolean isWhiteListed;

                boolean shouldApplyRestriction;

                final int targetSDK;

                final boolean hasRequestedLegacyExternalStorage;

                final boolean hasWriteMediaStorageGrantedForUid;

                final boolean isScopedStorageEnabled;



                if (appInfo != null) {

                    PackageManager pm = context.getPackageManager();

                    int flags = pm.getPermissionFlags(permission, appInfo.packageName, user);

                    isWhiteListed = (flags & FLAGS_PERMISSION_RESTRICTION_ANY_EXEMPT) != 0;

                    targetSDK = getMinimumTargetSDK(context, appInfo, user);

                    shouldApplyRestriction = (flags & FLAG_PERMISSION_APPLY_RESTRICTION) != 0

                            || targetSDK > Build.VERSION_CODES.Q;

                    hasRequestedLegacyExternalStorage = hasUidRequestedLegacyExternalStorage(

                            appInfo.uid, context);

                    hasWriteMediaStorageGrantedForUid = hasWriteMediaStorageGrantedForUid(

                            appInfo.uid, context);

                    final boolean isScopedStorageRequired =

                            isChangeEnabledForUid(context, appInfo, user, REQUIRE_SCOPED_STORAGE);

                    isScopedStorageEnabled =

                            isChangeEnabledForUid(context, appInfo, user, ENABLE_SCOPED_STORAGE)

                            || isScopedStorageRequired;

                    shouldApplyRestriction = (flags & FLAG_PERMISSION_APPLY_RESTRICTION) != 0

                            || isScopedStorageRequired;

                } else {

                    isWhiteListed = false;

                    shouldApplyRestriction = false;

                    targetSDK = 0;

                    hasRequestedLegacyExternalStorage = false;

                    hasWriteMediaStorageGrantedForUid = false;

                    isScopedStorageEnabled = false;

                }



                // We have a check in PermissionPolicyService.PermissionToOpSynchroniser.setUidMode
@@ -144,7 +140,7 @@ public abstract class SoftRestrictedPermissionPolicy { 
                return new SoftRestrictedPermissionPolicy() {

                    @Override

                    public boolean mayGrantPermission() {

                        return isWhiteListed || targetSDK >= Build.VERSION_CODES.Q;

                        return isWhiteListed || isScopedStorageEnabled;

                    }

                    @Override

                    public int getExtraAppOpCode() {
@@ -152,7 +148,7 @@ public abstract class SoftRestrictedPermissionPolicy { 
                    }

                    @Override

                    public boolean mayAllowExtraAppOp() {

                        return !shouldApplyRestriction && targetSDK <= Build.VERSION_CODES.Q

                        return !shouldApplyRestriction

                                && (hasRequestedLegacyExternalStorage

                                        || hasWriteMediaStorageGrantedForUid);

                    }
@@ -164,22 +160,26 @@ public abstract class SoftRestrictedPermissionPolicy { 
            }

            case WRITE_EXTERNAL_STORAGE: {

                final boolean isWhiteListed;

                final int targetSDK;

                final boolean isScopedStorageEnabled;



                if (appInfo != null) {

                    final int flags = context.getPackageManager().getPermissionFlags(permission,

                            appInfo.packageName, user);

                    isWhiteListed = (flags & FLAGS_PERMISSION_RESTRICTION_ANY_EXEMPT) != 0;

                    targetSDK = getMinimumTargetSDK(context, appInfo, user);

                    final boolean isScopedStorageRequired =

                            isChangeEnabledForUid(context, appInfo, user, REQUIRE_SCOPED_STORAGE);

                    isScopedStorageEnabled =

                            isChangeEnabledForUid(context, appInfo, user, ENABLE_SCOPED_STORAGE)

                            || isScopedStorageRequired;

                } else {

                    isWhiteListed = false;

                    targetSDK = 0;

                    isScopedStorageEnabled = false;

                }



                return new SoftRestrictedPermissionPolicy() {

                    @Override

                    public boolean mayGrantPermission() {

                        return isWhiteListed || targetSDK >= Build.VERSION_CODES.Q;

                        return isWhiteListed || isScopedStorageEnabled;

                    }

                };

            }
@@ -188,6 +188,62 @@ public abstract class SoftRestrictedPermissionPolicy { 
        }

    }



    /**

     * Checks whether an AppCompat change is enabled for all packages sharing a UID with the

     * provided application.

     *

     * @param context A context to use.

     * @param appInfo The application for which to check whether the compat change is enabled.

     * @param user The user the app belongs to.

     * @param changeId A {@link android.compat.annotation.ChangeId} corresponding to the change.

     *

     * @return true if this change is enabled for all apps sharing the UID of the provided app,

     *         false otherwise.

     */

    private static boolean isChangeEnabledForUid(@NonNull Context context,

            @NonNull ApplicationInfo appInfo, @NonNull UserHandle user, long changeId) {

        PackageManager pm = context.getPackageManager();



        String[] uidPackages = pm.getPackagesForUid(appInfo.uid);

        if (uidPackages != null) {

            for (String uidPackage : uidPackages) {

                ApplicationInfo uidPackageInfo;

                try {

                    uidPackageInfo = pm.getApplicationInfoAsUser(uidPackage, 0, user);

                } catch (PackageManager.NameNotFoundException e) {

                    continue;

                }

                if (!isChangeEnabled(uidPackageInfo, changeId)) {

                    // At least one package sharing this UID does not have this change enabled.

                    return false;

                }

            }

            // All packages sharing this UID returned true for {@link #isChangeEnabled()}.

            return true;

        } else {

            Log.w(LOG_TAG, "Check for change " + changeId + " for uid " + appInfo.uid

                    + " produced no packages. Defaulting to using the information for "

                    + appInfo.packageName + " only.");

            return isChangeEnabled(appInfo, changeId);

        }

    }



    private static boolean isChangeEnabled(@NonNull ApplicationInfo appInfo, long changeId) {

        IBinder binder = ServiceManager.getService(Context.PLATFORM_COMPAT_SERVICE);

        IPlatformCompat platformCompat = IPlatformCompat.Stub.asInterface(binder);



        final long callingId = Binder.clearCallingIdentity();



        try {

            return platformCompat.isChangeEnabled(changeId, appInfo);

        } catch (RemoteException e) {

            Log.e(LOG_TAG, "Check for change " + changeId + " failed. Defaulting to enabled.", e);

            return true;

        } finally {

            Binder.restoreCallingIdentity(callingId);

        }

    }



    private static boolean hasUidRequestedLegacyExternalStorage(int uid, @NonNull Context context) {

        PackageManager packageManager = context.getPackageManager();

        String[] packageNames = packageManager.getPackagesForUid(uid);