From d22e9dfb6a6ee7d86f50bf3b13c0588889e5dc53 Mon Sep 17 00:00:00 2001
From: Hongming Jin <hongmingjin@google.com>
Date: Fri, 18 May 2018 10:47:57 -0700
Subject: [PATCH] Backporting of b/77821568

Enforce permission check before returning application info
Test: manually tested (see bug for repro steps)
Bug: 77821568

Change-Id: Iec13196250f0e5d8b54fd7060ed40e3fe3fe2827
Merged-In: I7554805c36c0c2552163dad7b07cfc5f552b624e
---
 .../server/pm/PackageManagerService.java      | 27 ++++++++++++++++---
 1 file changed, 24 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 5ed6640599052..ea7d0cc3e4ad8 100644
--- a/services/core/java/com/android/server/pm/PackageManagerService.java
+++ b/services/core/java/com/android/server/pm/PackageManagerService.java
@@ -4473,7 +4473,9 @@ public class PackageManagerService extends IPackageManager.Stub
             triaged = false;
         }
         if ((flags & PackageManager.MATCH_ANY_USER) != 0) {
-            enforceCrossUserPermission(Binder.getCallingUid(), userId, false, false,
+            // require the permission to be held; the calling uid and given user id referring
+            // to the same user is not sufficient
+            enforceCrossUserPermission(Binder.getCallingUid(), userId, false, false, true,
                     "MATCH_ANY_USER flag requires INTERACT_ACROSS_USERS permission at "
                     + Debug.getCallers(5));
         } else if ((flags & PackageManager.MATCH_UNINSTALLED_PACKAGES) != 0 && isCallerSystemUser
@@ -5126,13 +5128,25 @@ public class PackageManagerService extends IPackageManager.Stub
      */
     void enforceCrossUserPermission(int callingUid, int userId, boolean requireFullPermission,
             boolean checkShell, String message) {
+        enforceCrossUserPermission(
+              callingUid,
+              userId,
+              requireFullPermission,
+              checkShell,
+              false,
+              message);
+    }
+
+    private void enforceCrossUserPermission(int callingUid, int userId,
+            boolean requireFullPermission, boolean checkShell,
+            boolean requirePermissionWhenSameUser, String message) {
         if (userId < 0) {
             throw new IllegalArgumentException("Invalid userId " + userId);
         }
         if (checkShell) {
             enforceShellRestriction(UserManager.DISALLOW_DEBUGGING_FEATURES, callingUid, userId);
         }
-        if (userId == UserHandle.getUserId(callingUid)) return;
+        if (!requirePermissionWhenSameUser && userId == UserHandle.getUserId(callingUid)) return;
         if (callingUid != Process.SYSTEM_UID && callingUid != 0) {
             if (requireFullPermission) {
                 mContext.enforceCallingOrSelfPermission(
@@ -8194,7 +8208,7 @@ public class PackageManagerService extends IPackageManager.Stub
         flags = updateFlagsForPackage(flags, userId, null);
         final boolean listUninstalled = (flags & MATCH_KNOWN_PACKAGES) != 0;
         enforceCrossUserPermission(callingUid, userId,
-                true /* requireFullPermission */, false /* checkShell */,
+                false /* requireFullPermission */, false /* checkShell */,
                 "get installed packages");
 
         // writer
@@ -8318,6 +8332,13 @@ public class PackageManagerService extends IPackageManager.Stub
         flags = updateFlagsForApplication(flags, userId, null);
         final boolean listUninstalled = (flags & MATCH_KNOWN_PACKAGES) != 0;
 
+        enforceCrossUserPermission(
+            callingUid,
+            userId,
+            false /* requireFullPermission */,
+            false /* checkShell */,
+            "get installed application info");
+
         // writer
         synchronized (mPackages) {
             ArrayList<ApplicationInfo> list;