From 8f0fa02c30f33237c18f75166a63666657551b7d Mon Sep 17 00:00:00 2001
From: Nikita Ioffe <ioffe@google.com>
Date: Fri, 18 Jun 2021 16:03:20 +0100
Subject: [PATCH] allocateSpaceForUpdate: clear calling identity before calling
 into apexd.

Additionally, enforce that callers of allocateSpaceForUpdate have
RECOVERY permission.

Test: presubmit
Bug: 189369298
Change-Id: Id4082d4774a0961c30bf47c7fae0dd3cd65d8908
---
 .../android/server/recoverysystem/RecoverySystemService.java  | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/services/core/java/com/android/server/recoverysystem/RecoverySystemService.java b/services/core/java/com/android/server/recoverysystem/RecoverySystemService.java
index ed4a7bf107d1f..f72adb609f6fb 100644
--- a/services/core/java/com/android/server/recoverysystem/RecoverySystemService.java
+++ b/services/core/java/com/android/server/recoverysystem/RecoverySystemService.java
@@ -961,11 +961,13 @@ public class RecoverySystemService extends IRecoverySystem.Stub implements Reboo
 
     @Override
     public boolean allocateSpaceForUpdate(String packageFile) {
+        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.RECOVERY, null);
         if (!isUpdatableApexSupported()) {
             Log.i(TAG, "Updatable Apex not supported, "
                     + "allocateSpaceForUpdate does nothing.");
             return true;
         }
+        final long token = Binder.clearCallingIdentity();
         try {
             CompressedApexInfoList apexInfoList = getCompressedApexInfoList(packageFile);
             ApexManager apexManager = ApexManager.getInstance();
@@ -975,6 +977,8 @@ public class RecoverySystemService extends IRecoverySystem.Stub implements Reboo
             e.rethrowAsRuntimeException();
         } catch (IOException | UnsupportedOperationException e) {
             Slog.e(TAG, "Failed to reserve space for compressed apex: ", e);
+        } finally {
+            Binder.restoreCallingIdentity(token);
         }
         return false;
     }