diff --git a/core/java/android/os/incremental/IncrementalManager.java b/core/java/android/os/incremental/IncrementalManager.java
index 9c8ee562849cd..80041437d6b82 100644
--- a/core/java/android/os/incremental/IncrementalManager.java
+++ b/core/java/android/os/incremental/IncrementalManager.java
@@ -25,6 +25,9 @@ import android.content.pm.DataLoaderParams;
 import android.content.pm.IPackageLoadingProgressCallback;
 import android.os.RemoteCallbackList;
 import android.os.RemoteException;
+import android.system.ErrnoException;
+import android.system.Os;
+import android.system.StructStat;
 import android.util.Slog;
 import android.util.SparseArray;
 
@@ -146,15 +149,29 @@ public final class IncrementalManager {
     @Nullable
     public IncrementalStorage createStorage(@NonNull String path,
             @NonNull IncrementalStorage linkedStorage, @CreateMode int createMode) {
+        int id = -1;
         try {
-            final int id = mService.createLinkedStorage(
+            // Incremental service mounts its newly created storage on top of the supplied path,
+            // ensure that the original mode remains the same after mounting.
+            StructStat st = Os.stat(path);
+            id = mService.createLinkedStorage(
                     path, linkedStorage.getId(), createMode);
             if (id < 0) {
                 return null;
             }
+            Os.chmod(path, st.st_mode & 07777);
             return new IncrementalStorage(mService, id);
         } catch (RemoteException e) {
             throw e.rethrowFromSystemServer();
+        } catch (ErrnoException e) {
+            if (id >= 0) {
+                try {
+                    mService.deleteStorage(id);
+                } catch (RemoteException re) {
+                    throw re.rethrowFromSystemServer();
+                }
+            }
+            throw new RuntimeException(e);
         }
     }
 
diff --git a/services/core/java/com/android/server/pm/InitAppsHelper.java b/services/core/java/com/android/server/pm/InitAppsHelper.java
index 12b5ab8a3160c..823bc71229438 100644
--- a/services/core/java/com/android/server/pm/InitAppsHelper.java
+++ b/services/core/java/com/android/server/pm/InitAppsHelper.java
@@ -39,6 +39,8 @@ import android.annotation.Nullable;
 import android.os.Environment;
 import android.os.SystemClock;
 import android.os.Trace;
+import android.system.ErrnoException;
+import android.system.Os;
 import android.util.ArrayMap;
 import android.util.EventLog;
 import android.util.Slog;
@@ -55,6 +57,7 @@ import com.android.server.pm.pkg.parsing.ParsingPackageUtils;
 import com.android.server.utils.WatchedArrayMap;
 
 import java.io.File;
+import java.nio.file.Files;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.ExecutorService;
@@ -226,6 +229,24 @@ final class InitAppsHelper {
         }
     }
 
+    /**
+     * Fix up the previously-installed app directory mode - they can't be readable by non-system
+     * users to prevent them from listing the dir to discover installed package names.
+     */
+    void fixInstalledAppDirMode() {
+        try (var files = Files.newDirectoryStream(mPm.getAppInstallDir().toPath())) {
+            files.forEach(dir -> {
+                try {
+                    Os.chmod(dir.toString(), 0771);
+                } catch (ErrnoException e) {
+                    Slog.w(TAG, "Failed to fix an installed app dir mode", e);
+                }
+            });
+        } catch (Exception e) {
+            Slog.w(TAG, "Failed to walk the app install directory to fix the modes", e);
+        }
+    }
+
     /**
      * Install apps/updates from data dir and fix system apps that are affected.
      */
@@ -234,6 +255,11 @@ final class InitAppsHelper {
             long startTime) {
         EventLog.writeEvent(EventLogTags.BOOT_PROGRESS_PMS_DATA_SCAN_START,
                 SystemClock.uptimeMillis());
+
+        if ((mScanFlags & SCAN_FIRST_BOOT_OR_UPGRADE) == SCAN_FIRST_BOOT_OR_UPGRADE) {
+            fixInstalledAppDirMode();
+        }
+
         scanDirTracedLI(mPm.getAppInstallDir(), 0,
                 mScanFlags | SCAN_REQUIRE_KNOWN, packageParser, mExecutorService);
 
diff --git a/services/core/java/com/android/server/pm/InstallPackageHelper.java b/services/core/java/com/android/server/pm/InstallPackageHelper.java
index 7553370bf4c62..c959b4724b93a 100644
--- a/services/core/java/com/android/server/pm/InstallPackageHelper.java
+++ b/services/core/java/com/android/server/pm/InstallPackageHelper.java
@@ -1719,7 +1719,7 @@ final class InstallPackageHelper {
         final boolean onIncremental = mPm.mIncrementalManager != null
                 && isIncrementalPath(beforeCodeFile.getAbsolutePath());
         try {
-            makeDirRecursive(afterCodeFile.getParentFile(), 0775);
+            makeDirRecursive(afterCodeFile.getParentFile(), 0771);
             if (onIncremental) {
                 // Just link files here. The stage dir will be removed when the installation
                 // session is completed.