summaryrefslogtreecommitdiffstats
path: root/browser/app/winlauncher/freestanding/LoaderPrivateAPI.cpp
blob: fb65a2d40530030ffee3bdc0f19571e487526b3f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */

#include "LoaderPrivateAPI.h"

#include "mozilla/Assertions.h"
#include "mozilla/Types.h"
#include "mozilla/Unused.h"
#include "../DllBlocklistInit.h"
#include "../ErrorHandler.h"
#include "SharedSection.h"

using GlobalInitializerFn = void(__cdecl*)(void);

// Allocation of static initialization section for the freestanding library
#pragma section(".freestd$a", read)
__declspec(allocate(".freestd$a")) static const GlobalInitializerFn
    FreeStdStart = reinterpret_cast<GlobalInitializerFn>(0);

#pragma section(".freestd$z", read)
__declspec(allocate(".freestd$z")) static const GlobalInitializerFn FreeStdEnd =
    reinterpret_cast<GlobalInitializerFn>(0);

namespace mozilla {
namespace freestanding {

static RTL_RUN_ONCE gRunOnce = RTL_RUN_ONCE_INIT;

// The contract for this callback is identical to the InitOnceCallback from
// Win32 land; we're just using ntdll-layer types instead.
static ULONG NTAPI DoOneTimeInit(PRTL_RUN_ONCE aRunOnce, PVOID aParameter,
                                 PVOID* aContext) {
  // Invoke every static initializer in the .freestd section
  const GlobalInitializerFn* cur = &FreeStdStart + 1;
  while (cur < &FreeStdEnd) {
    if (*cur) {
      (*cur)();
    }

    ++cur;
  }

  return TRUE;
}

/**
 * This observer is only used until the mozglue observer connects itself.
 * All we do here is accumulate the module loads into a vector.
 * As soon as mozglue connects, we call |Forward| on mozglue's LoaderObserver
 * to pass our vector on for further processing. This object then becomes
 * defunct.
 */
class MOZ_ONLY_USED_TO_AVOID_STATIC_CONSTRUCTORS DefaultLoaderObserver final
    : public nt::LoaderObserver {
 public:
  constexpr DefaultLoaderObserver() : mModuleLoads(nullptr) {}

  void OnBeginDllLoad(void** aContext,
                      PCUNICODE_STRING aRequestedDllName) final {}
  bool SubstituteForLSP(PCUNICODE_STRING aLSPLeafName,
                        PHANDLE aOutHandle) final {
    return false;
  }
  void OnEndDllLoad(void* aContext, NTSTATUS aNtStatus,
                    ModuleLoadInfo&& aModuleLoadInfo) final;
  void Forward(nt::LoaderObserver* aNext) final;
  void OnForward(ModuleLoadInfoVec&& aInfo) final {
    MOZ_ASSERT_UNREACHABLE("Not valid in freestanding::DefaultLoaderObserver");
  }

 private:
  mozilla::nt::SRWLock mLock;
  ModuleLoadInfoVec* mModuleLoads;
};

class MOZ_ONLY_USED_TO_AVOID_STATIC_CONSTRUCTORS LoaderPrivateAPIImp final
    : public LoaderPrivateAPI {
 public:
  // LoaderAPI
  ModuleLoadInfo ConstructAndNotifyBeginDllLoad(
      void** aContext, PCUNICODE_STRING aRequestedDllName) final;
  bool SubstituteForLSP(PCUNICODE_STRING aLSPLeafName,
                        PHANDLE aOutHandle) final;
  void NotifyEndDllLoad(void* aContext, NTSTATUS aLoadNtStatus,
                        ModuleLoadInfo&& aModuleLoadInfo) final;
  nt::AllocatedUnicodeString GetSectionName(void* aSectionAddr) final;
  nt::LoaderAPI::InitDllBlocklistOOPFnPtr GetDllBlocklistInitFn() final;
  nt::LoaderAPI::HandleLauncherErrorFnPtr GetHandleLauncherErrorFn() final;
  nt::SharedSection* GetSharedSection() final;

  // LoaderPrivateAPI
  void NotifyBeginDllLoad(void** aContext,
                          PCUNICODE_STRING aRequestedDllName) final;
  void NotifyBeginDllLoad(ModuleLoadInfo& aModuleLoadInfo, void** aContext,
                          PCUNICODE_STRING aRequestedDllName) final;
  void SetObserver(nt::LoaderObserver* aNewObserver) final;
  bool IsDefaultObserver() const final;
  nt::MemorySectionNameBuf GetSectionNameBuffer(void* aSectionAddr) final;
};

static void Init() {
  DebugOnly<NTSTATUS> ntStatus =
      ::RtlRunOnceExecuteOnce(&gRunOnce, &DoOneTimeInit, nullptr, nullptr);
  MOZ_ASSERT(NT_SUCCESS(ntStatus));
}

}  // namespace freestanding
}  // namespace mozilla

static mozilla::freestanding::DefaultLoaderObserver gDefaultObserver;
static mozilla::freestanding::LoaderPrivateAPIImp gPrivateAPI;

static mozilla::nt::SRWLock gLoaderObserverLock;
static mozilla::nt::LoaderObserver* gLoaderObserver = &gDefaultObserver;
static CONDITION_VARIABLE gLoaderObserverNoOngoingLoadsCV =
    CONDITION_VARIABLE_INIT;
static mozilla::Atomic<uint32_t> gLoaderObserverOngoingLoadsCount(0);

namespace mozilla {
namespace freestanding {

LoaderPrivateAPI& gLoaderPrivateAPI = gPrivateAPI;

void DefaultLoaderObserver::OnEndDllLoad(void* aContext, NTSTATUS aNtStatus,
                                         ModuleLoadInfo&& aModuleLoadInfo) {
  // If the DLL load failed, or if the DLL was loaded by a previous request
  // and thus was not mapped by this request, we do not save the ModuleLoadInfo.
  if (!NT_SUCCESS(aNtStatus) || !aModuleLoadInfo.WasMapped()) {
    return;
  }

  nt::AutoExclusiveLock lock(mLock);
  if (!mModuleLoads) {
    mModuleLoads = RtlNew<ModuleLoadInfoVec>();
    if (!mModuleLoads) {
      return;
    }
  }

  Unused << mModuleLoads->emplaceBack(
      std::forward<ModuleLoadInfo>(aModuleLoadInfo));
}

/**
 * Pass mModuleLoads's data off to |aNext| for further processing.
 */
void DefaultLoaderObserver::Forward(nt::LoaderObserver* aNext) {
  MOZ_ASSERT(aNext);
  if (!aNext) {
    return;
  }

  ModuleLoadInfoVec* moduleLoads = nullptr;

  {  // Scope for lock
    nt::AutoExclusiveLock lock(mLock);
    moduleLoads = mModuleLoads;
    mModuleLoads = nullptr;
  }

  if (!moduleLoads) {
    return;
  }

  aNext->OnForward(std::move(*moduleLoads));
  RtlDelete(moduleLoads);
}

ModuleLoadInfo LoaderPrivateAPIImp::ConstructAndNotifyBeginDllLoad(
    void** aContext, PCUNICODE_STRING aRequestedDllName) {
  ModuleLoadInfo loadInfo(aRequestedDllName);

  NotifyBeginDllLoad(loadInfo, aContext, aRequestedDllName);

  return loadInfo;
}

bool LoaderPrivateAPIImp::SubstituteForLSP(PCUNICODE_STRING aLSPLeafName,
                                           PHANDLE aOutHandle) {
  // This method should only be called between NotifyBeginDllLoad and
  // NotifyEndDllLoad, so it is already protected against gLoaderObserver
  // change, through gLoaderObserverOngoingLoadsCount.
  MOZ_RELEASE_ASSERT(gLoaderObserverOngoingLoadsCount);

  return gLoaderObserver->SubstituteForLSP(aLSPLeafName, aOutHandle);
}

void LoaderPrivateAPIImp::NotifyEndDllLoad(void* aContext,
                                           NTSTATUS aLoadNtStatus,
                                           ModuleLoadInfo&& aModuleLoadInfo) {
  aModuleLoadInfo.SetEndLoadTimeStamp();

  if (NT_SUCCESS(aLoadNtStatus)) {
    aModuleLoadInfo.CaptureBacktrace();
  }

  // This method should only be called after a matching call to
  // NotifyBeginDllLoad, so it is already protected against gLoaderObserver
  // change, through gLoaderObserverOngoingLoadsCount.

  // We need to notify the observer that the DLL load has ended even when
  // |aLoadNtStatus| indicates a failure. This is to ensure that any resources
  // acquired by the observer during OnBeginDllLoad are cleaned up.
  gLoaderObserver->OnEndDllLoad(aContext, aLoadNtStatus,
                                std::move(aModuleLoadInfo));

  auto previousValue = gLoaderObserverOngoingLoadsCount--;
  MOZ_RELEASE_ASSERT(previousValue);
  if (previousValue == 1) {
    ::RtlWakeAllConditionVariable(&gLoaderObserverNoOngoingLoadsCV);
  }
}

nt::AllocatedUnicodeString LoaderPrivateAPIImp::GetSectionName(
    void* aSectionAddr) {
  const HANDLE kCurrentProcess = reinterpret_cast<HANDLE>(-1);

  nt::MemorySectionNameBuf buf;
  NTSTATUS ntStatus =
      ::NtQueryVirtualMemory(kCurrentProcess, aSectionAddr, MemorySectionName,
                             &buf, sizeof(buf), nullptr);
  if (!NT_SUCCESS(ntStatus)) {
    return nt::AllocatedUnicodeString();
  }

  return nt::AllocatedUnicodeString(&buf.mSectionFileName);
}

nt::LoaderAPI::InitDllBlocklistOOPFnPtr
LoaderPrivateAPIImp::GetDllBlocklistInitFn() {
  return &InitializeDllBlocklistOOP;
}

nt::LoaderAPI::HandleLauncherErrorFnPtr
LoaderPrivateAPIImp::GetHandleLauncherErrorFn() {
  return &HandleLauncherError;
}

nt::SharedSection* LoaderPrivateAPIImp::GetSharedSection() {
  return &gSharedSection;
}

nt::MemorySectionNameBuf LoaderPrivateAPIImp::GetSectionNameBuffer(
    void* aSectionAddr) {
  const HANDLE kCurrentProcess = reinterpret_cast<HANDLE>(-1);

  nt::MemorySectionNameBuf buf;
  NTSTATUS ntStatus =
      ::NtQueryVirtualMemory(kCurrentProcess, aSectionAddr, MemorySectionName,
                             &buf, sizeof(buf), nullptr);
  if (!NT_SUCCESS(ntStatus)) {
    return nt::MemorySectionNameBuf();
  }

  return buf;
}

void LoaderPrivateAPIImp::NotifyBeginDllLoad(
    void** aContext, PCUNICODE_STRING aRequestedDllName) {
  nt::AutoSharedLock lock(gLoaderObserverLock);
  ++gLoaderObserverOngoingLoadsCount;
  gLoaderObserver->OnBeginDllLoad(aContext, aRequestedDllName);
}

void LoaderPrivateAPIImp::NotifyBeginDllLoad(
    ModuleLoadInfo& aModuleLoadInfo, void** aContext,
    PCUNICODE_STRING aRequestedDllName) {
  NotifyBeginDllLoad(aContext, aRequestedDllName);
  aModuleLoadInfo.SetBeginLoadTimeStamp();
}

void LoaderPrivateAPIImp::SetObserver(nt::LoaderObserver* aNewObserver) {
  nt::LoaderObserver* prevLoaderObserver = nullptr;

  nt::AutoExclusiveLock lock(gLoaderObserverLock);
  while (gLoaderObserverOngoingLoadsCount) {
    NTSTATUS status = ::RtlSleepConditionVariableSRW(
        &gLoaderObserverNoOngoingLoadsCV, &gLoaderObserverLock, nullptr, 0);
    MOZ_RELEASE_ASSERT(NT_SUCCESS(status) && status != STATUS_TIMEOUT);
  }

  MOZ_ASSERT(aNewObserver);
  if (!aNewObserver) {
    // This is unlikely, but we always want a valid observer, so use the
    // gDefaultObserver if necessary.
    gLoaderObserver = &gDefaultObserver;
    return;
  }

  prevLoaderObserver = gLoaderObserver;
  gLoaderObserver = aNewObserver;

  MOZ_ASSERT(prevLoaderObserver);
  if (!prevLoaderObserver) {
    return;
  }

  // Now that we have a new observer, the previous observer must forward its
  // data on to the new observer for processing.
  prevLoaderObserver->Forward(aNewObserver);
}

bool LoaderPrivateAPIImp::IsDefaultObserver() const {
  nt::AutoSharedLock lock(gLoaderObserverLock);
  return gLoaderObserver == &gDefaultObserver;
}

void EnsureInitialized() { Init(); }

}  // namespace freestanding
}  // namespace mozilla