From cd87544fc72b290002b2dbfbcd4e44674f488905 Mon Sep 17 00:00:00 2001
From: clement rouault <clement.rouault@exatrack.com>
Date: Tue, 15 Jun 2021 15:32:23 +0200
Subject: [PATCH] Fix a concurrency error in simple_x86

---
 tests/test_simple_x86.py          | 34 +++++++++++++++++++++++++++++++
 windows/native_exec/simple_x86.py | 13 ++++++++----
 2 files changed, 43 insertions(+), 4 deletions(-)

diff --git a/tests/test_simple_x86.py b/tests/test_simple_x86.py
index 3ff8ec9..b3efe23 100644
--- a/tests/test_simple_x86.py
+++ b/tests/test_simple_x86.py
@@ -261,6 +261,40 @@ def test_x86_instr_multiply():
     res += x86.Ret()
     assert res.get_code() == b"\x90\x90\x90\x90\x90\xc3"
 
+import threading
+threads_error = []
+
+def test_x86_multithread_target():
+    try:
+
+        assert x86.Mov("ECX", "SS").get_code() == b"\x8c\xd1"
+        assert x86.Mov("SS", "ECX").get_code() == b"\x8e\xd1"
+        assert x86.Ret().get_code() == b"\xc3"
+
+        res = x86.MultipleInstr()
+        res += x86.Mov("ECX", "SS")
+        res += x86.Mov("SS", "ECX")
+        res += x86.Ret()
+        assert res.get_code() == b"\x8c\xd1\x8e\xd1\xc3"
+    except Exception as e:
+        threads_error.append(e)
+        raise
+    return True
+
+def test_x86_multithread():
+    all_threads = []
+    for tnb in range(10):
+        t = threading.Thread(target=test_x86_multithread_target)
+        all_threads.append(t)
+
+    # import pdb; pdb.set_trace()
+    for t in all_threads:
+        t.start()
+    for t in all_threads:
+        t.join()
+    assert not threads_error, "syswow call inconsistent with MultiThreading inconsistent"
+
+
 if capstone is None:
     test_assembler = pytest.mark.skip("Capstone not installed")(test_assembler)
 
diff --git a/windows/native_exec/simple_x86.py b/windows/native_exec/simple_x86.py
index 9879a13..0181c88 100644
--- a/windows/native_exec/simple_x86.py
+++ b/windows/native_exec/simple_x86.py
@@ -28,6 +28,12 @@ class BitArray(object):
         if size > len(self.array):
             self.array = ([0] * (size - len(self.array))) + self.array
 
+    def copy(self):
+        new = type(self)(0, "")
+        new.size = self.size
+        new.array = list(self.array)
+        return new
+
     def dump(self):
         res = []
         for i in range(self.size // 8):
@@ -283,7 +289,7 @@ RegisterEax = lambda: FixedRegister('EAX')
 
 class RawBits(BitArray):
     def accept_arg(self, args, instr_state):
-        return (0, self)
+        return (0, self.copy())
 
 
 # Immediat value logic
@@ -404,8 +410,6 @@ class SegmentSelectorAbsoluteAddr(object):
 
 
 
-
-
 class ModRM(object):
     def __init__(self, sub_modrm, accept_reverse=True, has_direction_bit=True):
         self.accept_reverse = accept_reverse
@@ -438,7 +442,6 @@ class ModRM_REG__REG(object):
     def match(cls, arg1, arg2):
         return X86.is_reg(arg1) and X86.is_reg(arg2)
 
-
     def __init__(self, arg1, arg2, reversed, instr_state):
         self.mod = BitArray(2, "11")
         if X86.reg_size(arg1) != X86.reg_size(arg2):
@@ -601,6 +604,7 @@ class Instruction(object):
     encoding = []
 
     def __init__(self, *initial_args):
+        # print(self, initial_args)
         for type_encoding in self.encoding:
             args = list(initial_args)
             prefix = []
@@ -620,6 +624,7 @@ class Instruction(object):
         raise ValueError("Cannot encode <{0} {1}>:(".format(type(self).__name__, initial_args))
 
     def get_code(self):
+        # print(self.value)
         prefix_opcode = b"".join(chr(p.PREFIX_VALUE) for p in self.prefix)
         return prefix_opcode + bytes(self.value.dump())