commit c3e509cacc41ca78611b1c8d0c34599f895cf009
author Bernardo Rufino <brufino@google.com> Fri Jan 19 17:00:05 2018 +0000
committer Bernardo Rufino <brufino@google.com> Fri Jan 19 19:02:09 2018 +0000
tree e5f35fa29fd6f82c7b265f87c2d2e57be66eaaa2
parent 5e1f854620ecf48febb6ef8ddc3bff856efda7b1

Clear calling uid in isAppEligibleForBackup() and variant

This method is called by bmgr backupnow. Bmgr pid is not system uid.
When executing the method it fails with permission denied because it
can't bind to the transport. Before binding on-demand we haven't seen
this error because we didn't try to bind in the method, it was always
bound.

Bug: 72215413
Test: adb shell bmgr backupnow -all
Change-Id: I82ad712e893abfec4727d568ab48a49945645eb4

services/backup/java/com/android/server/backup/RefactoredBackupManagerService.java

diff --git a/services/backup/java/com/android/server/backup/RefactoredBackupManagerService.java b/services/backup/java/com/android/server/backup/RefactoredBackupManagerService.java
index 5188910..93b179c 100644
--- a/services/backup/java/com/android/server/backup/RefactoredBackupManagerService.java
+++ b/services/backup/java/com/android/server/backup/RefactoredBackupManagerService.java
@@ -3464,16 +3464,21 @@
         mContext.enforceCallingOrSelfPermission(
                 android.Manifest.permission.BACKUP, "isAppEligibleForBackup");
 
-        String callerLogString = "BMS.isAppEligibleForBackup";
-        TransportClient transportClient =
-                mTransportManager.getCurrentTransportClient(callerLogString);
-        boolean eligible =
-                AppBackupUtils.appIsRunningAndEligibleForBackupWithTransport(
-                        transportClient, packageName, mPackageManager);
-        if (transportClient != null) {
-            mTransportManager.disposeOfTransportClient(transportClient, callerLogString);
+        long oldToken = Binder.clearCallingIdentity();
+        try {
+            String callerLogString = "BMS.isAppEligibleForBackup";
+            TransportClient transportClient =
+                    mTransportManager.getCurrentTransportClient(callerLogString);
+            boolean eligible =
+                    AppBackupUtils.appIsRunningAndEligibleForBackupWithTransport(
+                            transportClient, packageName, mPackageManager);
+            if (transportClient != null) {
+                mTransportManager.disposeOfTransportClient(transportClient, callerLogString);
+            }
+            return eligible;
+        } finally {
+            Binder.restoreCallingIdentity(oldToken);
         }
-        return eligible;
     }
 
     @Override
@@ -3481,21 +3486,26 @@
         mContext.enforceCallingOrSelfPermission(
                 android.Manifest.permission.BACKUP, "filterAppsEligibleForBackup");
 
-        String callerLogString = "BMS.filterAppsEligibleForBackup";
-        TransportClient transportClient =
-                mTransportManager.getCurrentTransportClient(callerLogString);
-        List<String> eligibleApps = new LinkedList<>();
-        for (String packageName : packages) {
-            if (AppBackupUtils
-                    .appIsRunningAndEligibleForBackupWithTransport(
-                            transportClient, packageName, mPackageManager)) {
-                eligibleApps.add(packageName);
+        long oldToken = Binder.clearCallingIdentity();
+        try {
+            String callerLogString = "BMS.filterAppsEligibleForBackup";
+            TransportClient transportClient =
+                    mTransportManager.getCurrentTransportClient(callerLogString);
+            List<String> eligibleApps = new LinkedList<>();
+            for (String packageName : packages) {
+                if (AppBackupUtils
+                        .appIsRunningAndEligibleForBackupWithTransport(
+                                transportClient, packageName, mPackageManager)) {
+                    eligibleApps.add(packageName);
+                }
             }
+            if (transportClient != null) {
+                mTransportManager.disposeOfTransportClient(transportClient, callerLogString);
+            }
+            return eligibleApps.toArray(new String[eligibleApps.size()]);
+        } finally {
+            Binder.restoreCallingIdentity(oldToken);
         }
-        if (transportClient != null) {
-            mTransportManager.disposeOfTransportClient(transportClient, callerLogString);
-        }
-        return eligibleApps.toArray(new String[eligibleApps.size()]);
     }
 
     @Override