remove old backstage injection and remove all legacy code

BackstageInjection-Rust/build.rs

@@ -31,23 +31,19 @@ fn main() {
 }
 
 fn generate_loader_entry() {
-    let name = match std::env::var("BACKSTAGE_LOADER_EXPORT").ok().as_deref() {
-        Some("ReflectiveLoader") => "ReflectiveLoader".to_string(),
-        Some(value) => panic!("unsupported BACKSTAGE_LOADER_EXPORT value: {value}"),
-        None => {
-            let seed = std::env::var("BACKSTAGE_LOADER_SEED")
-                .ok()
-                .and_then(|value| value.parse::<u64>().ok())
-                .unwrap_or_else(|| {
-                    SystemTime::now()
-                        .duration_since(UNIX_EPOCH)
-                        .unwrap()
-                        .as_nanos() as u64
-                        ^ (std::process::id() as u64).wrapping_mul(0x9E37_79B9_7F4A_7C15)
-                });
-            format!("x{:06x}", seed & 0xFFFF_FF)
-        }
-    };
+    // The loader export is always a per-build randomized `x<hex>` name. The
+    // legacy fixed `ReflectiveLoader` export is no longer supported.
+    let seed = std::env::var("BACKSTAGE_LOADER_SEED")
+        .ok()
+        .and_then(|value| value.parse::<u64>().ok())
+        .unwrap_or_else(|| {
+            SystemTime::now()
+                .duration_since(UNIX_EPOCH)
+                .unwrap()
+                .as_nanos() as u64
+                ^ (std::process::id() as u64).wrapping_mul(0x9E37_79B9_7F4A_7C15)
+        });
+    let name = format!("x{:06x}", seed & 0xFFFF_FF);
 
     let src = format!(
         "// Generated by build.rs — do not edit.\n\
@@ -63,6 +59,5 @@ fn generate_loader_entry() {
     let out_dir = std::env::var("OUT_DIR").unwrap();
     std::fs::write(std::path::Path::new(&out_dir).join("loader_entry.rs"), src)
         .expect("failed to write loader_entry.rs");
-    println!("cargo:rerun-if-env-changed=BACKSTAGE_LOADER_EXPORT");
     println!("cargo:rerun-if-env-changed=BACKSTAGE_LOADER_SEED");
 }

BackstageInjection-Rust/src/reflective.rs

@@ -1,11 +1,12 @@
 //! Position-independent reflective loader, pure Rust (no C).
 //!
-//! This is a direct port of the Harmony Security `ReflectiveLoader` that was
-//! previously compiled from `reflective/ReflectiveLoader.c`. The injection
-//! stubs (`inject_reflective`) copy this DLL's raw bytes into a remote process
-//! and start a thread on our exported `ReflectiveLoader`. When that thread
-//! begins, the copied image is *not* relocated and its imports are *not*
-//! resolved, so this function must be position independent end to end:
+//! This is a direct port of the Harmony Security `ReflectiveLoader` approach.
+//! The injection stubs (`inject_reflective`) copy this DLL's raw bytes into a
+//! remote process and start a thread on our exported loader entry, whose name
+//! is randomized per build (see build.rs) rather than a fixed string. When
+//! that thread begins, the copied image is *not* relocated and its imports
+//! are *not* resolved, so this function must be position independent end to
+//! end:
 //!
 //!   - It never reads relocatable data. All image structures are reached by
 //!     computing addresses at runtime and reading with volatile scalar loads.