libsanitizer/ubsan/ubsan_type_hash_win.cpp

   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 && defined(_MSC_VER)
  16 #include "ubsan_type_hash.h"
  17
  18 #include "sanitizer_common/sanitizer_common.h"
  19
  20 #include <typeinfo>
  21
  22 struct 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
  31 struct 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
  40 bool __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
  80 bool __ubsan::checkTypeInfoEquality(const void *, const void *) {
  81   return false;
  82 }
  83
  84 #endif  // CAN_SANITIZE_UB && SANITIZER_WINDOWS