1 files changed, 48 insertions, 31 deletions

diff --git a/services/core/java/com/android/server/content/ContentService.java b/services/core/java/com/android/server/content/ContentService.java
index f581a7f..1db31c9 100644
--- a/services/core/java/com/android/server/content/ContentService.java
+++ b/services/core/java/com/android/server/content/ContentService.java
@@ -19,6 +19,8 @@ package com.android.server.content;
 import android.Manifest;
 import android.accounts.Account;
 import android.app.ActivityManager;
+import android.app.ActivityManagerInternal;
+import android.app.ActivityManagerNative;
 import android.content.ComponentName;
 import android.content.ContentResolver;
 import android.content.Context;
@@ -51,7 +53,6 @@ import com.android.server.LocalServices;
 
 import java.io.FileDescriptor;
 import java.io.PrintWriter;
-import java.security.InvalidParameterException;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Comparator;
@@ -190,23 +191,15 @@ public final class ContentService extends IContentService.Stub {
 
         final int uid = Binder.getCallingUid();
         final int pid = Binder.getCallingPid();
-        final int callingUserHandle = UserHandle.getCallingUserId();
-        // Registering an observer for any user other than the calling user requires uri grant or
-        // cross user permission
-        if (callingUserHandle != userHandle &&
-                mContext.checkUriPermission(uri, pid, uid, Intent.FLAG_GRANT_READ_URI_PERMISSION)
-                        != PackageManager.PERMISSION_GRANTED) {
-            enforceCrossUserPermission(userHandle,
-                    "no permission to observe other users' provider view");
-        }
 
-        if (userHandle < 0) {
-            if (userHandle == UserHandle.USER_CURRENT) {
-                userHandle = ActivityManager.getCurrentUser();
-            } else if (userHandle != UserHandle.USER_ALL) {
-                throw new InvalidParameterException("Bad user handle for registerContentObserver: "
-                        + userHandle);
-            }
+        userHandle = handleIncomingUser(uri, pid, uid,
+                Intent.FLAG_GRANT_READ_URI_PERMISSION, userHandle);
+
+        final String msg = LocalServices.getService(ActivityManagerInternal.class)
+                .checkContentProviderAccess(uri.getAuthority(), userHandle);
+        if (msg != null) {
+            Log.w(TAG, "Ignoring content changes for " + uri + " from " + uid + ": " + msg);
+            return;
         }
 
         synchronized (mRootNode) {
@@ -253,21 +246,15 @@ public final class ContentService extends IContentService.Stub {
         final int uid = Binder.getCallingUid();
         final int pid = Binder.getCallingPid();
         final int callingUserHandle = UserHandle.getCallingUserId();
-        // Notify for any user other than the caller requires uri grant or cross user permission
-        if (callingUserHandle != userHandle &&
-                mContext.checkUriPermission(uri, pid, uid, Intent.FLAG_GRANT_WRITE_URI_PERMISSION)
-                        != PackageManager.PERMISSION_GRANTED) {
-            enforceCrossUserPermission(userHandle, "no permission to notify other users");
-        }
 
-        // We passed the permission check; resolve pseudouser targets as appropriate
-        if (userHandle < 0) {
-            if (userHandle == UserHandle.USER_CURRENT) {
-                userHandle = ActivityManager.getCurrentUser();
-            } else if (userHandle != UserHandle.USER_ALL) {
-                throw new InvalidParameterException("Bad user handle for notifyChange: "
-                        + userHandle);
-            }
+        userHandle = handleIncomingUser(uri, pid, uid,
+                Intent.FLAG_GRANT_WRITE_URI_PERMISSION, userHandle);
+
+        final String msg = LocalServices.getService(ActivityManagerInternal.class)
+                .checkContentProviderAccess(uri.getAuthority(), userHandle);
+        if (msg != null) {
+            Log.w(TAG, "Ignoring notify for " + uri + " from " + uid + ": " + msg);
+            return;
         }
 
         // This makes it so that future permission checks will be in the context of this
@@ -317,6 +304,15 @@ public final class ContentService extends IContentService.Stub {
         }
     }
 
+    private int checkUriPermission(Uri uri, int pid, int uid, int modeFlags, int userHandle) {
+        try {
+            return ActivityManagerNative.getDefault().checkUriPermission(
+                    uri, pid, uid, modeFlags, userHandle, null);
+        } catch (RemoteException e) {
+            return PackageManager.PERMISSION_DENIED;
+        }
+    }
+
     public void notifyChange(Uri uri, IContentObserver observer,
             boolean observerWantsSelfNotifications, boolean syncToNetwork) {
         notifyChange(uri, observer, observerWantsSelfNotifications, syncToNetwork,
@@ -924,6 +920,27 @@ public final class ContentService extends IContentService.Stub {
         return service;
     }
 
+    private int handleIncomingUser(Uri uri, int pid, int uid, int modeFlags, int userId) {
+        if (userId == UserHandle.USER_CURRENT) {
+            userId = ActivityManager.getCurrentUser();
+        }
+
+        if (userId == UserHandle.USER_ALL) {
+            mContext.enforceCallingOrSelfPermission(
+                    Manifest.permission.INTERACT_ACROSS_USERS_FULL, TAG);
+        } else if (userId < 0) {
+            throw new IllegalArgumentException("Invalid user: " + userId);
+        } else if (userId != UserHandle.getCallingUserId()) {
+            if (checkUriPermission(uri, pid, uid, modeFlags,
+                    userId) != PackageManager.PERMISSION_GRANTED) {
+                mContext.enforceCallingOrSelfPermission(
+                        Manifest.permission.INTERACT_ACROSS_USERS_FULL, TAG);
+            }
+        }
+
+        return userId;
+    }
+
     /**
      * Checks if the request is from the system or an app that has INTERACT_ACROSS_USERS_FULL
      * permission, if the userHandle is not for the caller.