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Commit d23b3971 authored by Nate Myren's avatar Nate Myren Committed by Anis Assi
Browse files

Revoke storage on SDK downgrade or new full storage request 

When an app downgrades from above API 28 to below, or when an app begins
requesting full storage in api 29, revoke storage permissions

Test: Atest StorageEscalationTest
Bug: 171430330
Merged-In: Ia6bd5658b77a26ab15fea013ec875050457473e0
Change-Id: Ia6bd5658b77a26ab15fea013ec875050457473e0
(cherry picked from commit ed2ff0f5)
parent f93dd8db

services/core/java/com/android/server/pm/PackageManagerService.java

+2 −0
Original line number Diff line number Diff line
@@ -12318,6 +12318,8 @@ public class PackageManagerService extends IPackageManager.Stub 
                    if (hasOldPkg) {

                        mPermissionManager.revokeRuntimePermissionsIfGroupChanged(pkg, oldPkg,

                                allPackageNames, mPermissionCallback);

                        mPermissionManager.revokeStoragePermissionsIfScopeExpanded(pkg, oldPkg,

                                mPermissionCallback);

                    }

                    if (hasPermissionDefinitionChanges) {

                        mPermissionManager.revokeRuntimePermissionsIfPermissionDefinitionChanged(

services/core/java/com/android/server/pm/permission/PermissionManagerService.java

+65 −0
Original line number Diff line number Diff line
@@ -150,6 +150,9 @@ public class PermissionManagerService { 
    private static final int USER_PERMISSION_FLAGS = FLAG_PERMISSION_USER_SET

            | FLAG_PERMISSION_USER_FIXED;



    /** All storage permissions */

    private static final List<String> STORAGE_PERMISSIONS = new ArrayList<>();



    /** If the permission of the value is granted, so is the key */

    private static final Map<String, String> FULLER_PERMISSION_MAP = new HashMap<>();
@@ -158,6 +161,9 @@ public class PermissionManagerService { 
                Manifest.permission.ACCESS_FINE_LOCATION);

        FULLER_PERMISSION_MAP.put(Manifest.permission.INTERACT_ACROSS_USERS,

                Manifest.permission.INTERACT_ACROSS_USERS_FULL);

        STORAGE_PERMISSIONS.add(Manifest.permission.READ_EXTERNAL_STORAGE);

        STORAGE_PERMISSIONS.add(Manifest.permission.WRITE_EXTERNAL_STORAGE);

        STORAGE_PERMISSIONS.add(Manifest.permission.ACCESS_MEDIA_LOCATION);

    }



    /** Lock to protect internal data access */
@@ -589,6 +595,50 @@ public class PermissionManagerService { 
        return protectionLevel;

    }



    /**

     * If the app is updated, and has scoped storage permissions, then it is possible that the

     * app updated in an attempt to get unscoped storage. If so, revoke all storage permissions.

     * @param newPackage The new package that was installed

     * @param oldPackage The old package that was updated

     */

    private void revokeStoragePermissionsIfScopeExpanded(

            @NonNull PackageParser.Package newPackage,

            @NonNull PackageParser.Package oldPackage,

            @NonNull PermissionCallback permissionCallback) {

        boolean downgradedSdk = oldPackage.applicationInfo.targetSdkVersion >= Build.VERSION_CODES.Q

                && newPackage.applicationInfo.targetSdkVersion < Build.VERSION_CODES.Q;

        boolean upgradedSdk = oldPackage.applicationInfo.targetSdkVersion < Build.VERSION_CODES.Q

                && newPackage.applicationInfo.targetSdkVersion >= Build.VERSION_CODES.Q;

        boolean newlyRequestsLegacy = !upgradedSdk

                && !oldPackage.applicationInfo.hasRequestedLegacyExternalStorage()

                && newPackage.applicationInfo.hasRequestedLegacyExternalStorage();



        if (!newlyRequestsLegacy && !downgradedSdk) {

            return;

        }



        final int callingUid = Binder.getCallingUid();

        final int userId = UserHandle.getUserId(newPackage.applicationInfo.uid);

        int numRequestedPermissions = newPackage.requestedPermissions.size();

        for (int i = 0; i < numRequestedPermissions; i++) {

            PermissionInfo permInfo = getPermissionInfo(newPackage.requestedPermissions.get(i),

                    newPackage.packageName, 0, callingUid);

            if (permInfo == null || !STORAGE_PERMISSIONS.contains(permInfo.name)) {

                continue;

            }



            EventLog.writeEvent(0x534e4554, "171430330", newPackage.applicationInfo.uid,

                    "Revoking permission " + permInfo.name + " from package "

                            + newPackage.packageName + " as either the sdk downgraded "

                            + downgradedSdk + " or newly requested legacy full storage "

                            + newlyRequestsLegacy);



            revokeRuntimePermission(permInfo.name, newPackage.packageName,

                    false, userId, permissionCallback);

        }



    }



    /**

     * We might auto-grant permissions if any permission of the group is already granted. Hence if

     * the group of a granted permission changes we need to revoke it to avoid having permissions of
@@ -3105,6 +3155,21 @@ public class PermissionManagerService { 
        public boolean isPermissionsReviewRequired(@NonNull Package pkg, @UserIdInt int userId) {

            return PermissionManagerService.this.isPermissionsReviewRequired(pkg, userId);

        }



        /**

         * If the app is updated, and has scoped storage permissions, then it is possible that the

         * app updated in an attempt to get unscoped storage. If so, revoke all storage permissions.

         * @param newPackage The new package that was installed

         * @param oldPackage The old package that was updated

         */

        public void revokeStoragePermissionsIfScopeExpanded(

                @NonNull PackageParser.Package newPackage,

                @NonNull PackageParser.Package oldPackage,

                @NonNull PermissionCallback permissionCallback) {

            PermissionManagerService.this.revokeStoragePermissionsIfScopeExpanded(newPackage,

                    oldPackage, permissionCallback);

        }



        @Override

        public void revokeRuntimePermissionsIfGroupChanged(

                @NonNull PackageParser.Package newPackage,

services/core/java/com/android/server/pm/permission/PermissionManagerServiceInternal.java

+11 −0
Original line number Diff line number Diff line
@@ -126,6 +126,17 @@ public abstract class PermissionManagerServiceInternal extends PermissionManager 
            @NonNull ArrayList<String> allPackageNames,

            @NonNull PermissionCallback permissionCallback);



    /**

     * If the app is updated, and has scoped storage permissions, then it is possible that the

     * app updated in an attempt to get unscoped storage. If so, revoke all storage permissions.

     * @param newPackage The new package that was installed

     * @param oldPackage The old package that was updated

     */

    public abstract void revokeStoragePermissionsIfScopeExpanded(

            @NonNull PackageParser.Package newPackage,

            @NonNull PackageParser.Package oldPackage,

            @NonNull PermissionCallback permissionCallback);



    /**

     * Add all permissions in the given package.

     * <p>