From 3eddf406755d6ab18acb46f9550c997ca4bb1970 Mon Sep 17 00:00:00 2001
From: Jeff Sharkey <jsharkey@android.com>
Date: Wed, 30 Nov 2016 14:29:59 -0700
Subject: [PATCH] DO NOT MERGE. Grant MMS Uri permissions as the calling UID.

A recent security fix prevents the system UID from handing out Uri
permission grants directly from itself.  Instead, services need to
issue grants as the original calling UID to ensure that the caller
actually has access to the Uris.

Test: builds, boots, send/recv MMS works in primary/secondary users
Bug: 33231106
Change-Id: Ia9fe19843b52977c8a94ee5349b907beda1882fc
(cherry picked from commit 7ff418d9a9afb9ecf42f87fffd3e65477decb55e)
---
 .../java/android/app/ActivityManagerInternal.java |  7 +++++++
 .../java/com/android/server/MmsServiceBroker.java | 15 +++++++++++++--
 .../android/server/am/ActivityManagerService.java |  9 +++++++++
 3 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/core/java/android/app/ActivityManagerInternal.java b/core/java/android/app/ActivityManagerInternal.java
index d4f80a01ea534..28f84771e10ce 100644
--- a/core/java/android/app/ActivityManagerInternal.java
+++ b/core/java/android/app/ActivityManagerInternal.java
@@ -60,6 +60,13 @@ public abstract class ActivityManagerInternal {
      */
     public static final int APP_TRANSITION_TIMEOUT = 3;
 
+    /**
+     * Grant Uri permissions from one app to another. This method only extends
+     * permission grants if {@code callingUid} has permission to them.
+     */
+    public abstract void grantUriPermissionFromIntent(int callingUid, String targetPkg,
+            Intent intent, int targetUserId);
+
     /**
      * Verify that calling app has access to the given provider.
      */
diff --git a/services/core/java/com/android/server/MmsServiceBroker.java b/services/core/java/com/android/server/MmsServiceBroker.java
index 33f92344f6159..54b2a25aa3bbb 100644
--- a/services/core/java/com/android/server/MmsServiceBroker.java
+++ b/services/core/java/com/android/server/MmsServiceBroker.java
@@ -17,6 +17,7 @@
 package com.android.server;
 
 import android.Manifest;
+import android.app.ActivityManagerInternal;
 import android.app.AppOpsManager;
 import android.app.PendingIntent;
 import android.content.ComponentName;
@@ -499,13 +500,21 @@ public class MmsServiceBroker extends SystemService {
          */
         private Uri adjustUriForUserAndGrantPermission(Uri contentUri, String action,
                 int permission) {
+            final Intent grantIntent = new Intent();
+            grantIntent.setData(contentUri);
+            grantIntent.setFlags(permission);
+
+            final int callingUid = Binder.getCallingUid();
             final int callingUserId = UserHandle.getCallingUserId();
             if (callingUserId != UserHandle.USER_SYSTEM) {
                 contentUri = ContentProvider.maybeAddUserId(contentUri, callingUserId);
             }
+
             long token = Binder.clearCallingIdentity();
             try {
-                mContext.grantUriPermission(PHONE_PACKAGE_NAME, contentUri, permission);
+                LocalServices.getService(ActivityManagerInternal.class)
+                        .grantUriPermissionFromIntent(callingUid, PHONE_PACKAGE_NAME,
+                                grantIntent, UserHandle.USER_SYSTEM);
 
                 // Grant permission for the carrier app.
                 Intent intent = new Intent(action);
@@ -514,7 +523,9 @@ public class MmsServiceBroker extends SystemService {
                 List<String> carrierPackages = telephonyManager.getCarrierPackageNamesForIntent(
                         intent);
                 if (carrierPackages != null && carrierPackages.size() == 1) {
-                    mContext.grantUriPermission(carrierPackages.get(0), contentUri, permission);
+                    LocalServices.getService(ActivityManagerInternal.class)
+                            .grantUriPermissionFromIntent(callingUid, carrierPackages.get(0),
+                                    grantIntent, UserHandle.USER_SYSTEM);
                 }
             } finally {
                 Binder.restoreCallingIdentity(token);
diff --git a/services/core/java/com/android/server/am/ActivityManagerService.java b/services/core/java/com/android/server/am/ActivityManagerService.java
index 1fe3ee2d8e128..da34a92c087b1 100644
--- a/services/core/java/com/android/server/am/ActivityManagerService.java
+++ b/services/core/java/com/android/server/am/ActivityManagerService.java
@@ -21897,6 +21897,15 @@ public final class ActivityManagerService extends ActivityManagerNative
     }
 
     private final class LocalService extends ActivityManagerInternal {
+        @Override
+        public void grantUriPermissionFromIntent(int callingUid, String targetPkg, Intent intent,
+                int targetUserId) {
+            synchronized (ActivityManagerService.this) {
+                ActivityManagerService.this.grantUriPermissionFromIntentLocked(callingUid,
+                        targetPkg, intent, null, targetUserId);
+            }
+        }
+
         @Override
         public String checkContentProviderAccess(String authority, int userId) {
             return ActivityManagerService.this.checkContentProviderAccess(authority, userId);