From c1a00b23582bdb5e43478c4efd0a3ad60cb5a1ea Mon Sep 17 00:00:00 2001
From: Nikos Gorogiannis <nikosgorogiannis@fb.com>
Date: Fri, 25 Jan 2019 06:16:02 -0800
Subject: [PATCH] [classloads] restrict loads via fields

Reviewed By: ezgicicek

Differential Revision: D13817232

fbshipit-source-id: 470d5ce11
---
 infer/src/concurrency/classLoads.ml           | 23 +++++++----
 .../codetoanalyze/java/classloads/Fields.java | 41 +++++++++++++++++++
 .../codetoanalyze/java/classloads/Static.java |  4 +-
 3 files changed, 59 insertions(+), 9 deletions(-)
 create mode 100644 infer/tests/codetoanalyze/java/classloads/Fields.java

diff --git a/infer/src/concurrency/classLoads.ml b/infer/src/concurrency/classLoads.ml
index 18b9efccc..f2647950e 100644
--- a/infer/src/concurrency/classLoads.ml
+++ b/infer/src/concurrency/classLoads.ml
@@ -7,11 +7,19 @@
 open! IStd
 module L = Logging
 
+(* Sources: Java Virtual Machine Specification 
+   - Chapter 5. Loading, Linking and Initializing
+   - Chapter 6. The Java Virtual Machine Instruction Set
+*)
+
 (* TODO 
-  - Casts 
-  - Const literals for class objects?  
+  - Casts (checkcast)
+  - instanceof
+  - Const literals for class objects? (ldc / ldc_w)
   - catch / throw with exception classes 
-  *)
+  - sync(class object)
+  - multidimensional arrays (multinewarray) ? 
+*)
 
 module Payload = SummaryPayload.Make (struct
   type t = ClassLoadsDomain.summary
@@ -58,9 +66,8 @@ let add_type proc_desc tenv loc typ astate =
 
 let rec add_loads_of_exp proc_desc tenv loc (exp : Exp.t) (typ : Typ.t) astate =
   match exp with
-  | Lvar _ ->
-      add_type proc_desc tenv loc typ astate
   | Sizeof {typ= {desc= Tarray {elt}}} ->
+      (* anewarray *)
       add_type proc_desc tenv loc elt astate
   | Cast (_, e) | UnOp (_, e, _) | Exn e ->
       add_loads_of_exp proc_desc tenv loc e typ astate
@@ -68,14 +75,16 @@ let rec add_loads_of_exp proc_desc tenv loc (exp : Exp.t) (typ : Typ.t) astate =
       add_loads_of_exp proc_desc tenv loc e1 typ astate
       |> add_loads_of_exp proc_desc tenv loc e2 typ
   | Lfield (e, _, typ') ->
-      add_loads_of_exp proc_desc tenv loc e typ' astate
-  | Var _ | Const _ | Closure _ | Sizeof _ | Lindex _ ->
+      (* getfield / getstatic / putfield / putstatic *)
+      add_type proc_desc tenv loc typ' astate |> add_loads_of_exp proc_desc tenv loc e typ'
+  | Var _ | Const _ | Closure _ | Sizeof _ | Lindex _ | Lvar _ ->
       astate
 
 
 let exec_instr pdesc tenv astate _ (instr : Sil.instr) =
   match instr with
   | Call (_, Const (Cfun callee), args, loc, _) ->
+      (* invokeinterface / invokespecial / invokestatic / invokevirtual / new *)
       List.fold args ~init:astate ~f:(fun acc (exp, typ) ->
           add_loads_of_exp pdesc tenv loc exp typ acc )
       |> do_call pdesc callee loc
diff --git a/infer/tests/codetoanalyze/java/classloads/Fields.java b/infer/tests/codetoanalyze/java/classloads/Fields.java
new file mode 100644
index 000000000..d8985ce1a
--- /dev/null
+++ b/infer/tests/codetoanalyze/java/classloads/Fields.java
@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2018-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+class Fields {
+  FieldsA a;
+
+  Fields() {
+    a = new FieldsA();
+  }
+
+  void foo() {
+    System.out.println(a.b.c);
+  }
+
+  public static void main(String args[]) {
+    Fields f = new Fields();
+    f.foo();
+  }
+}
+
+class FieldsA {
+  FieldsA() {
+    b = new FieldsB();
+  }
+
+  FieldsB b;
+}
+
+class FieldsB {
+  FieldsB() {
+    c = null;
+  }
+
+  FieldsCNoLoad c;
+}
+
+class FieldsCNoLoad {}
diff --git a/infer/tests/codetoanalyze/java/classloads/Static.java b/infer/tests/codetoanalyze/java/classloads/Static.java
index c6194035f..be9b14c91 100644
--- a/infer/tests/codetoanalyze/java/classloads/Static.java
+++ b/infer/tests/codetoanalyze/java/classloads/Static.java
@@ -22,10 +22,10 @@ class StaticA {
 
 class StaticB {
   // no load here
-  static StaticC c = null;
+  static StaticCNoLoad c = null;
 }
 
-class StaticC {}
+class StaticCNoLoad {}
 
 class StaticD {
   static int static_data = 5;