Framework and system_server classes can access public vendor libraries

This CL fixes a regression caused by [1] which introduced
<uses-native-library> tag [2]. With the change, public vendor libraries
[3] became accessible only when they are listed in the caller's
AndroidManifest.xml using the new tag. However, this caused a problem to
the places where AndroidManifest.xml doesn't exist: framework and
system_server classes. For those cases, [1] incorrectly used a null list
as the requested native libraries, and as a result, no public vendor
libraries were accessible.

This CL fixes the issue by not doing the filtering for the class loaders
created for non-app contexts like zygote or system_server. Specifically,
it uses the magic keyword "ALL" which let libnativeloader.so
accept all public vendor libraries.

[1] https://android.googlesource.com/platform/frameworks/base/+/6a5b8b1f6db172b5aaadcec0c3868e54e214b675
[2] https://developer.android.com/guide/topics/manifest/uses-native-library-element
[3] https://source.android.com/devices/tech/config/namespaces_libraries#adding-additional-native-libraries

Bug: 205164833
Test: libcuttlefish_fs.so is loaded when built with the other CLs in the
same topic

Change-Id: Id92c59642773851d70d05a05f43eb5873e9de86b

1 files changed, 15 insertions, 3 deletions

diff --git a/core/java/com/android/internal/os/ClassLoaderFactory.java b/core/java/com/android/internal/os/ClassLoaderFactory.java
index 8b0411de5477..8f5e97d40530 100644
--- a/core/java/com/android/internal/os/ClassLoaderFactory.java
+++ b/core/java/com/android/internal/os/ClassLoaderFactory.java
@@ -24,6 +24,7 @@ import dalvik.system.DelegateLastClassLoader;
 import dalvik.system.DexClassLoader;
 import dalvik.system.PathClassLoader;
 
+import java.util.ArrayList;
 import java.util.List;
 
 /**
@@ -100,14 +101,25 @@ public class ClassLoaderFactory {
     }
 
     /**
-     * Same as {@code createClassLoader} below, but passes a null list of shared
-     * libraries.
+     * Same as {@code createClassLoader} below, but passes a null list of shared libraries. This
+     * method is used only to load platform classes (i.e. those in framework.jar or services.jar),
+     * and MUST NOT be used for loading untrusted classes, especially the app classes. For the
+     * latter case, use the below method which accepts list of shared libraries so that the classes
+     * don't have unlimited access to all shared libraries.
      */
     public static ClassLoader createClassLoader(String dexPath,
             String librarySearchPath, String libraryPermittedPath, ClassLoader parent,
             int targetSdkVersion, boolean isNamespaceShared, String classLoaderName) {
+        // b/205164833: allow framework classes to have access to all public vendor libraries.
+        // This is because those classes are part of the platform and don't have an app manifest
+        // where required libraries can be specified using the <uses-native-library> tag.
+        // Note that this still does not give access to "private" vendor libraries.
+        List<String> nativeSharedLibraries = new ArrayList<>();
+        nativeSharedLibraries.add("ALL");
+
         return createClassLoader(dexPath, librarySearchPath, libraryPermittedPath,
-            parent, targetSdkVersion, isNamespaceShared, classLoaderName, null, null, null);
+            parent, targetSdkVersion, isNamespaceShared, classLoaderName, null,
+            nativeSharedLibraries, null);
     }
 
     /**