From b86bf0822905cbeb20e9d6e2dedf2b2edd98c144 Mon Sep 17 00:00:00 2001
From: Jean-Marie Mineau <jean-marie.mineau@inria.fr>
Date: Wed, 2 Apr 2025 16:45:26 +0200
Subject: [PATCH] model delegate last behavior

---
 patcher/src/code_loading_patcher.rs | 24 ++++++++++++++++--------
 patcher/src/dex_types.rs            |  2 ++
 2 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/patcher/src/code_loading_patcher.rs b/patcher/src/code_loading_patcher.rs
index 1535325..5f7a704 100644
--- a/patcher/src/code_loading_patcher.rs
+++ b/patcher/src/code_loading_patcher.rs
@@ -5,14 +5,9 @@ use androscalpel::{Apk, DexString, IdType, VisitorMut};
 use anyhow::{Context, Result};
 use clap::ValueEnum;
 
+use crate::dex_types::DELEGATE_LAST_CLASS_LOADER;
 use crate::runtime_data::RuntimeData;
 
-// TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO
-//
-// INSERT EMPTY CLASS LOADERS WHEN ID REFERS TO UNKNOWN CLASS LOADER
-//
-// TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO
-
 #[derive(ValueEnum, Debug, PartialEq, Clone, Copy, Default)]
 pub enum CodePatchingStrategy {
     #[default]
@@ -70,7 +65,10 @@ fn insert_code_model_class_loaders(apk: &mut Apk, runtime_data: &mut RuntimeData
             apk.add_code(file, crate::labeling, false)?;
         }
 
-        assert!(!class_loaders.contains_key(&dyn_data.classloader));
+        assert!(
+            !class_loaders.contains_key(&dyn_data.classloader),
+            "The same class loader should not appear twice in runtime_data.dyn_code_load"
+        );
 
         let classes = apk.list_classes();
         let mut class_loader = ClassLoader {
@@ -305,7 +303,14 @@ impl ClassLoader<'_> {
         ty: &IdType,
         class_loaders: &HashMap<String, Self>,
     ) -> Option<IdType> {
-        // TODO: Implemente different class loader behaviors
+        // TODO: Check Platform Classes
+        if self.class == *DELEGATE_LAST_CLASS_LOADER {
+            if let Some(new_ty) = self.renamed_classes.get(ty) {
+                return Some(new_ty.clone());
+            } else if self.apk().get_class(ty).is_some() {
+                return Some(ty.clone());
+            }
+        }
         if let Some(ref parent_id) = self.parent {
             if let Some(parent) = class_loaders.get(parent_id) {
                 if let Some(new_ty) = parent.get_ref_new_name(ty, class_loaders) {
@@ -315,6 +320,9 @@ impl ClassLoader<'_> {
                 log::warn!("Class Loader {}({}) has parent {}, but parent was not found in class loader list", self.id, self.class.__str__(), parent_id);
             }
         }
+        if self.class == *DELEGATE_LAST_CLASS_LOADER {
+            return None;
+        }
         if let Some(new_ty) = self.renamed_classes.get(ty) {
             Some(new_ty.clone())
         } else if self.apk().get_class(ty).is_some() {
diff --git a/patcher/src/dex_types.rs b/patcher/src/dex_types.rs
index 110a388..08f5d6f 100644
--- a/patcher/src/dex_types.rs
+++ b/patcher/src/dex_types.rs
@@ -102,6 +102,8 @@ pub(crate) static SCAL_TO_OBJ_DOUBLE: LazyLock<IdMethod> = LazyLock::new(|| {
 
 pub(crate) static OBJECT_TY: LazyLock<IdType> =
     LazyLock::new(|| IdType::from_smali("Ljava/lang/Object;").unwrap());
+pub(crate) static DELEGATE_LAST_CLASS_LOADER: LazyLock<IdType> =
+    LazyLock::new(|| IdType::from_smali("Ldalvik/system/DelegateLastClassLoader;").unwrap());
 
 /// Get the method that convert a object to its scalar conterpart (eg `java.lang.Integer` to `int` with
 /// `Ljava/lang/Integer;->intValue()I`)