ubsan_type_hash_win.cpp revision 360784 
1//===-- ubsan_type_hash_win.cpp -------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// Implementation of type hashing/lookup for Microsoft C++ ABI.
10//
11//===----------------------------------------------------------------------===//
12
13#include "sanitizer_common/sanitizer_platform.h"
14#include "ubsan_platform.h"
15#if CAN_SANITIZE_UB && SANITIZER_WINDOWS
16#include "ubsan_type_hash.h"
17
18#include "sanitizer_common/sanitizer_common.h"
19
20#include <typeinfo>
21
22struct CompleteObjectLocator {
23  int is_image_relative;
24  int offset_to_top;
25  int vfptr_offset;
26  int rtti_addr;
27  int chd_addr;
28  int obj_locator_addr;
29};
30
31struct CompleteObjectLocatorAbs {
32  int is_image_relative;
33  int offset_to_top;
34  int vfptr_offset;
35  std::type_info *rtti_addr;
36  void *chd_addr;
37  CompleteObjectLocator *obj_locator_addr;
38};
39
40bool __ubsan::checkDynamicType(void *Object, void *Type, HashValue Hash) {
41  // FIXME: Implement.
42  return false;
43}
44
45__ubsan::DynamicTypeInfo
46__ubsan::getDynamicTypeInfoFromVtable(void *VtablePtr) {
47  // The virtual table may not have a complete object locator if the object
48  // was compiled without RTTI (i.e. we might be reading from some other global
49  // laid out before the virtual table), so we need to carefully validate each
50  // pointer dereference and perform sanity checks.
51  CompleteObjectLocator **obj_locator_ptr =
52    ((CompleteObjectLocator**)VtablePtr)-1;
53  if (!IsAccessibleMemoryRange((uptr)obj_locator_ptr, sizeof(void*)))
54    return DynamicTypeInfo(0, 0, 0);
55
56  CompleteObjectLocator *obj_locator = *obj_locator_ptr;
57  if (!IsAccessibleMemoryRange((uptr)obj_locator,
58                               sizeof(CompleteObjectLocator)))
59    return DynamicTypeInfo(0, 0, 0);
60
61  std::type_info *tinfo;
62  if (obj_locator->is_image_relative == 1) {
63    char *image_base = ((char *)obj_locator) - obj_locator->obj_locator_addr;
64    tinfo = (std::type_info *)(image_base + obj_locator->rtti_addr);
65  } else if (obj_locator->is_image_relative == 0)
66    tinfo = ((CompleteObjectLocatorAbs *)obj_locator)->rtti_addr;
67  else
68    // Probably not a complete object locator.
69    return DynamicTypeInfo(0, 0, 0);
70
71  if (!IsAccessibleMemoryRange((uptr)tinfo, sizeof(std::type_info)))
72    return DynamicTypeInfo(0, 0, 0);
73
74  // Okay, this is probably a std::type_info. Request its name.
75  // FIXME: Implement a base class search like we do for Itanium.
76  return DynamicTypeInfo(tinfo->name(), obj_locator->offset_to_top,
77                         "<unknown>");
78}
79
80bool __ubsan::checkTypeInfoEquality(const void *, const void *) {
81  return false;
82}
83
84#endif  // CAN_SANITIZE_UB && SANITIZER_WINDOWS
85