From 3aa2123a4c877289517e3dcb0a2579a42322b228 Mon Sep 17 00:00:00 2001
From: Jackal Guo <jackalguo@google.com>
Date: Wed, 9 Nov 2022 14:35:20 +0800
Subject: [PATCH] Validate EXTRA_INSTALLER_PACKAGE_NAME

When installing an app via ACTION_INSTALL_PACKAGE, the caller could
use this extra field to specify the installer package name. As using
PackageInstaller APIs, we should limit setting the installer package
name that is not the caller only when apps with INSTALL_PACKAGES
permission. Also applying the max package name length restriction.

Bug: 236687884
Test: atest CtsPackageInstallTestCases
Test: manually using the PoC in the buganizer to ensure the symptom
      no longer exists.
Change-Id: I74eb4ea2e2733321b5fbf328a9835a3ca7d0dfa9
---
 .../packageinstaller/InstallStart.java        | 20 +++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/packages/PackageInstaller/src/com/android/packageinstaller/InstallStart.java b/packages/PackageInstaller/src/com/android/packageinstaller/InstallStart.java
index bfab9bec1cbc4..e4bdab89532b9 100644
--- a/packages/PackageInstaller/src/com/android/packageinstaller/InstallStart.java
+++ b/packages/PackageInstaller/src/com/android/packageinstaller/InstallStart.java
@@ -28,6 +28,7 @@ import android.content.Intent;
 import android.content.pm.ApplicationInfo;
 import android.content.pm.PackageInfo;
 import android.content.pm.PackageInstaller;
+import android.content.pm.PackageInstaller.SessionParams;
 import android.content.pm.PackageManager;
 import android.content.pm.PackageManager.NameNotFoundException;
 import android.content.pm.ProviderInfo;
@@ -35,6 +36,8 @@ import android.net.Uri;
 import android.os.Build;
 import android.os.Bundle;
 import android.os.RemoteException;
+import android.text.TextUtils;
+import android.util.EventLog;
 import android.util.Log;
 
 import java.util.Arrays;
@@ -96,6 +99,23 @@ public class InstallStart extends Activity {
                 mAbortInstall = true;
             }
         }
+
+        final String installerPackageNameFromIntent = getIntent().getStringExtra(
+                Intent.EXTRA_INSTALLER_PACKAGE_NAME);
+        if (installerPackageNameFromIntent != null) {
+            final String callingPkgName = getLaunchedFromPackage();
+            if (installerPackageNameFromIntent.length() >= SessionParams.MAX_PACKAGE_NAME_LENGTH
+                    || (!TextUtils.equals(installerPackageNameFromIntent, callingPkgName)
+                    && mPackageManager.checkPermission(Manifest.permission.INSTALL_PACKAGES,
+                    callingPkgName) != PackageManager.PERMISSION_GRANTED)) {
+                Log.e(LOG_TAG, "The given installer package name " + installerPackageNameFromIntent
+                        + " is invalid. Remove it.");
+                EventLog.writeEvent(0x534e4554, "236687884", getLaunchedFromUid(),
+                        "Invalid EXTRA_INSTALLER_PACKAGE_NAME");
+                getIntent().removeExtra(Intent.EXTRA_INSTALLER_PACKAGE_NAME);
+            }
+        }
+
         if (mAbortInstall) {
             setResult(RESULT_CANCELED);
             finish();