From 19a569ab3d060610a9d252e23f12dc8e30195521 Mon Sep 17 00:00:00 2001
From: Todd Kennedy <toddke@google.com>
Date: Wed, 22 May 2019 08:54:58 -0700
Subject: [PATCH] Ensure packages in shared user are valid

Package information is tracked by several different structures
and updated in different synchronized blocks. As such, the set
of packages that are part of a shared user are updated after
the set of installed packages is updated. And, in some cases,
a removed package will still be listed as a member of a shared
user id.

Before passing a package to the PermissionManager to check
for permission grants, ensure the package actually exists and
is known to the system.

Bug: 111075456
Test: Manual. Builds and runs.
Change-Id: Ibb4f44f50141d43bf2367747d6d5813648d42fd4
---
 .../server/pm/PackageManagerService.java       | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/services/core/java/com/android/server/pm/PackageManagerService.java b/services/core/java/com/android/server/pm/PackageManagerService.java
index e07a132844571..ac6cb72d73650 100644
--- a/services/core/java/com/android/server/pm/PackageManagerService.java
+++ b/services/core/java/com/android/server/pm/PackageManagerService.java
@@ -5646,9 +5646,11 @@ public class PackageManagerService extends IPackageManager.Stub
     private int checkUidPermissionImpl(String permName, int uid) {
         synchronized (mPackages) {
             final String[] packageNames = getPackagesForUid(uid);
-            final PackageParser.Package pkg = (packageNames != null && packageNames.length > 0)
-                    ? mPackages.get(packageNames[0])
-                    : null;
+            PackageParser.Package pkg = null;
+            final int N = packageNames == null ? 0 : packageNames.length;
+            for (int i = 0; pkg == null && i < N; i++) {
+                pkg = mPackages.get(packageNames[i]);
+            }
             // Additional logs for b/111075456; ignore system UIDs
             if (pkg == null && UserHandle.getAppId(uid) >= Process.FIRST_APPLICATION_UID) {
                 if (packageNames == null || packageNames.length < 2) {
@@ -6385,6 +6387,16 @@ public class PackageManagerService extends IPackageManager.Stub
         }
     }
 
+    /**
+     * <em>IMPORTANT:</em> Not all packages returned by this method may be known
+     * to the system. There are two conditions in which this may occur:
+     * <ol>
+     *   <li>The package is on adoptable storage and the device has been removed</li>
+     *   <li>The package is being removed and the internal structures are partially updated</li>
+     * </ol>
+     * The second is an artifact of the current data structures and should be fixed. See
+     * b/111075456 for one such instance.
+     */
     @Override
     public String[] getPackagesForUid(int uid) {
         return getPackagesForUid_debug(uid, false);