1    :  // Copyright 2015 Google Inc. All Rights Reserved.
   2    :  //
   3    :  // Licensed under the Apache License, Version 2.0 (the "License");
   4    :  // you may not use this file except in compliance with the License.
   5    :  // You may obtain a copy of the License at
   6    :  //
   7    :  //     http://www.apache.org/licenses/LICENSE-2.0
   8    :  //
   9    :  // Unless required by applicable law or agreed to in writing, software
  10    :  // distributed under the License is distributed on an "AS IS" BASIS,
  11    :  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12    :  // See the License for the specific language governing permissions and
  13    :  // limitations under the License.
  14    :  
  15    :  #include "syzygy/agent/asan/memory_interceptors_patcher.h"
  16    :  
  17    :  #include "gtest/gtest.h"
  18    :  #include "syzygy/agent/asan/memory_interceptors.h"
  19    :  #include "syzygy/agent/asan/shadow.h"
  20    :  
  21    :  // The linker satisfies this symbol. This gets us a pointer to our own module
  22    :  // when we're loaded.
  23    :  extern "C" IMAGE_DOS_HEADER __ImageBase;
  24    :  
  25    :  namespace agent {
  26    :  namespace asan {
  27    :  
  28    :  namespace {
  29    :  
  30  E :  void ExpectShadowReferencesTo(const uint8_t* shadow_memory) {
  31  E :    for (const void** cursor = asan_shadow_references; *cursor != 0; ++cursor) {
  32  E :      EXPECT_EQ(shadow_memory, *reinterpret_cast<uint8_t const* const*>(*cursor));
  33  E :    }
  34  E :  }
  35    :  
  36    :  }  // namespace
  37    :  
  38  E :  TEST(MemoryInterceptorPatcherTest, PatchMemoryInterceptorShadowReferences) {
  39    :    // The references should initially be to the static shadow memory.
  40    :    EXPECT_NO_FATAL_FAILURE(
  41  E :        ExpectShadowReferencesTo(asan_memory_interceptors_shadow_memory));
  42    :  
  43    :    // Patch the references to point to a new shadow memory.
  44  E :    uint8_t dummy_shadow[1] = {};
  45    :    EXPECT_TRUE(PatchMemoryInterceptorShadowReferences(
  46  E :        asan_memory_interceptors_shadow_memory, dummy_shadow));
  47  E :    EXPECT_NO_FATAL_FAILURE(ExpectShadowReferencesTo(dummy_shadow));
  48    :  
  49    :    // Try patching again. The 'current' shadow memory matching will fail
  50    :    // and the functions should still point to the new shadow.
  51    :    EXPECT_FALSE(PatchMemoryInterceptorShadowReferences(
  52  E :        asan_memory_interceptors_shadow_memory, dummy_shadow));
  53  E :    EXPECT_NO_FATAL_FAILURE(ExpectShadowReferencesTo(dummy_shadow));
  54    :  
  55    :    // Patch this back to the original shadow memory so the unittest leaves no
  56    :    // side effects.
  57    :    EXPECT_TRUE(PatchMemoryInterceptorShadowReferences(
  58  E :        dummy_shadow, asan_memory_interceptors_shadow_memory));
  59    :    EXPECT_NO_FATAL_FAILURE(
  60  E :        ExpectShadowReferencesTo(asan_memory_interceptors_shadow_memory));
  61  E :  }
  62    :  
  63    :  }  // namespace asan
  64    :  }  // namespace agent