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-rw-r--r--browser/app/winlauncher/freestanding/SharedSection.cpp368
1 files changed, 368 insertions, 0 deletions
diff --git a/browser/app/winlauncher/freestanding/SharedSection.cpp b/browser/app/winlauncher/freestanding/SharedSection.cpp
new file mode 100644
index 0000000000..eab0074f60
--- /dev/null
+++ b/browser/app/winlauncher/freestanding/SharedSection.cpp
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+/* -*- 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 "SharedSection.h"
+
+#include <algorithm>
+#include "CheckForCaller.h"
+#include "mozilla/BinarySearch.h"
+
+namespace {
+
+bool AddString(mozilla::Span<wchar_t> aBuffer, const UNICODE_STRING& aStr) {
+ size_t offsetElements = 0;
+ while (offsetElements < aBuffer.Length()) {
+ UNICODE_STRING uniStr;
+ ::RtlInitUnicodeString(&uniStr, aBuffer.data() + offsetElements);
+
+ if (uniStr.Length == 0) {
+ // Reached to the array's last item.
+ break;
+ }
+
+ if (::RtlCompareUnicodeString(&uniStr, &aStr, TRUE) == 0) {
+ // Already included in the array.
+ return true;
+ }
+
+ // Go to the next string.
+ offsetElements += uniStr.MaximumLength / sizeof(wchar_t);
+ }
+
+ // Ensure enough space including the last empty string at the end.
+ if (offsetElements * sizeof(wchar_t) + aStr.Length + sizeof(wchar_t) +
+ sizeof(wchar_t) >
+ aBuffer.LengthBytes()) {
+ return false;
+ }
+
+ auto newStr = aBuffer.Subspan(offsetElements);
+ memcpy(newStr.data(), aStr.Buffer, aStr.Length);
+ memset(newStr.data() + aStr.Length / sizeof(wchar_t), 0, sizeof(wchar_t));
+ return true;
+}
+
+} // anonymous namespace
+
+namespace mozilla {
+namespace freestanding {
+
+SharedSection gSharedSection;
+
+// Why don't we use ::GetProcAddress?
+// If the export table of kernel32.dll is tampered in the current process,
+// we cannot transfer an RVA because the function pointed by the RVA may not
+// exist in a target process.
+// We can use ::GetProcAddress with additional check to detect tampering, but
+// FindExportAddressTableEntry fits perfectly here because it returns nullptr
+// if the target entry is outside the image, which means it's tampered or
+// forwarded to another DLL.
+#define INIT_FUNCTION(exports, name) \
+ do { \
+ auto rvaToFunction = exports.FindExportAddressTableEntry(#name); \
+ if (!rvaToFunction) { \
+ return; \
+ } \
+ m##name = reinterpret_cast<decltype(m##name)>(*rvaToFunction); \
+ } while (0)
+
+#define RESOLVE_FUNCTION(base, name) \
+ m##name = reinterpret_cast<decltype(m##name)>( \
+ base + reinterpret_cast<uintptr_t>(m##name))
+
+void Kernel32ExportsSolver::Init() {
+ interceptor::MMPolicyInProcess policy;
+ auto k32Exports = nt::PEExportSection<interceptor::MMPolicyInProcess>::Get(
+ ::GetModuleHandleW(L"kernel32.dll"), policy);
+ if (!k32Exports) {
+ return;
+ }
+
+ // Please make sure these functions are not forwarded to another DLL.
+ INIT_FUNCTION(k32Exports, FlushInstructionCache);
+ INIT_FUNCTION(k32Exports, GetModuleHandleW);
+ INIT_FUNCTION(k32Exports, GetSystemInfo);
+ INIT_FUNCTION(k32Exports, VirtualProtect);
+}
+
+bool Kernel32ExportsSolver::Resolve() {
+ const UNICODE_STRING k32Name = MOZ_LITERAL_UNICODE_STRING(L"kernel32.dll");
+
+ // We cannot use GetModuleHandleW because this code can be called
+ // before IAT is resolved.
+ auto k32Module = nt::GetModuleHandleFromLeafName(k32Name);
+ if (k32Module.isErr()) {
+ // Probably this is called before kernel32.dll is loaded.
+ return false;
+ }
+
+ uintptr_t k32Base =
+ nt::PEHeaders::HModuleToBaseAddr<uintptr_t>(k32Module.unwrap());
+
+ RESOLVE_FUNCTION(k32Base, FlushInstructionCache);
+ RESOLVE_FUNCTION(k32Base, GetModuleHandleW);
+ RESOLVE_FUNCTION(k32Base, GetSystemInfo);
+ RESOLVE_FUNCTION(k32Base, VirtualProtect);
+
+ return true;
+}
+
+HANDLE SharedSection::sSectionHandle = nullptr;
+SharedSection::Layout* SharedSection::sWriteCopyView = nullptr;
+RTL_RUN_ONCE SharedSection::sEnsureOnce = RTL_RUN_ONCE_INIT;
+nt::SRWLock SharedSection::sLock;
+
+void SharedSection::Reset(HANDLE aNewSectionObject) {
+ nt::AutoExclusiveLock{sLock};
+ if (sWriteCopyView) {
+ nt::AutoMappedView view(sWriteCopyView);
+ sWriteCopyView = nullptr;
+ ::RtlRunOnceInitialize(&sEnsureOnce);
+ }
+
+ if (sSectionHandle != aNewSectionObject) {
+ if (sSectionHandle) {
+ ::CloseHandle(sSectionHandle);
+ }
+ sSectionHandle = aNewSectionObject;
+ }
+}
+
+void SharedSection::ConvertToReadOnly() {
+ if (!sSectionHandle) {
+ return;
+ }
+
+ HANDLE readonlyHandle;
+ if (!::DuplicateHandle(nt::kCurrentProcess, sSectionHandle,
+ nt::kCurrentProcess, &readonlyHandle, GENERIC_READ,
+ FALSE, 0)) {
+ return;
+ }
+
+ Reset(readonlyHandle);
+}
+
+LauncherVoidResult SharedSection::Init() {
+ static_assert(
+ kSharedViewSize >= sizeof(Layout),
+ "kSharedViewSize is too small to represent SharedSection::Layout.");
+
+ HANDLE section =
+ ::CreateFileMappingW(INVALID_HANDLE_VALUE, nullptr, PAGE_READWRITE, 0,
+ kSharedViewSize, nullptr);
+ if (!section) {
+ return LAUNCHER_ERROR_FROM_LAST();
+ }
+ Reset(section);
+
+ // The initial contents of the pages in a file mapping object backed by
+ // the operating system paging file are 0 (zero). No need to zero it out
+ // ourselves.
+ // https://docs.microsoft.com/en-us/windows/win32/api/memoryapi/nf-memoryapi-createfilemappingw
+ nt::AutoMappedView writableView(sSectionHandle, PAGE_READWRITE);
+ if (!writableView) {
+ return LAUNCHER_ERROR_FROM_LAST();
+ }
+
+ Layout* view = writableView.as<Layout>();
+ view->mK32Exports.Init();
+ view->mState = Layout::State::kInitialized;
+ // Leave view->mDependentModulePathArrayStart to be zero to indicate
+ // we can add blocklist entries
+ return Ok();
+}
+
+LauncherVoidResult SharedSection::AddDependentModule(PCUNICODE_STRING aNtPath) {
+ nt::AutoMappedView writableView(sSectionHandle, PAGE_READWRITE);
+ if (!writableView) {
+ return LAUNCHER_ERROR_FROM_WIN32(::RtlGetLastWin32Error());
+ }
+
+ Layout* view = writableView.as<Layout>();
+ if (!view->mDependentModulePathArrayStart) {
+ // This is the first time AddDependentModule is called. We set the initial
+ // value to mDependentModulePathArrayStart, which *closes* the blocklist.
+ // After this, AddBlocklist is no longer allowed.
+ view->mDependentModulePathArrayStart =
+ FIELD_OFFSET(Layout, mFirstBlockEntry) + sizeof(DllBlockInfo);
+ }
+
+ if (!AddString(view->GetDependentModules(), *aNtPath)) {
+ return LAUNCHER_ERROR_FROM_WIN32(ERROR_INSUFFICIENT_BUFFER);
+ }
+
+ return Ok();
+}
+
+LauncherVoidResult SharedSection::SetBlocklist(
+ const DynamicBlockList& aBlocklist, bool isDisabled) {
+ if (!aBlocklist.GetPayloadSize()) {
+ return Ok();
+ }
+
+ nt::AutoMappedView writableView(sSectionHandle, PAGE_READWRITE);
+ if (!writableView) {
+ return LAUNCHER_ERROR_FROM_WIN32(::RtlGetLastWin32Error());
+ }
+
+ Layout* view = writableView.as<Layout>();
+ if (view->mDependentModulePathArrayStart > 0) {
+ // If the dependent module array is already available, we must not update
+ // the blocklist.
+ return LAUNCHER_ERROR_FROM_WIN32(ERROR_INVALID_STATE);
+ }
+
+ view->mBlocklistIsDisabled = isDisabled ? 1 : 0;
+ uintptr_t bufferEnd = reinterpret_cast<uintptr_t>(view) + kSharedViewSize;
+ size_t bytesCopied = aBlocklist.CopyTo(
+ view->mFirstBlockEntry,
+ bufferEnd - reinterpret_cast<uintptr_t>(view->mFirstBlockEntry));
+ if (!bytesCopied) {
+ return LAUNCHER_ERROR_FROM_WIN32(ERROR_INSUFFICIENT_BUFFER);
+ }
+
+ // Setting mDependentModulePathArrayStart to a non-zero value means
+ // we no longer accept blocklist entries
+ // Just to be safe, make sure we don't overwrite mFirstBlockEntry even
+ // if there are no entries.
+ view->mDependentModulePathArrayStart =
+ FIELD_OFFSET(Layout, mFirstBlockEntry) +
+ std::max(bytesCopied, sizeof(DllBlockInfo));
+ return Ok();
+}
+
+/* static */
+ULONG NTAPI SharedSection::EnsureWriteCopyViewOnce(PRTL_RUN_ONCE, PVOID,
+ PVOID*) {
+ if (!sWriteCopyView) {
+ nt::AutoMappedView view(sSectionHandle, PAGE_WRITECOPY);
+ if (!view) {
+ return TRUE;
+ }
+ sWriteCopyView = view.as<Layout>();
+ view.release();
+ }
+ return sWriteCopyView->Resolve() ? TRUE : FALSE;
+}
+
+SharedSection::Layout* SharedSection::EnsureWriteCopyView(
+ bool requireKernel32Exports /*= false */) {
+ ::RtlRunOnceExecuteOnce(&sEnsureOnce, &EnsureWriteCopyViewOnce, nullptr,
+ nullptr);
+ if (!sWriteCopyView) {
+ return nullptr;
+ }
+ auto requiredState = requireKernel32Exports
+ ? Layout::State::kResolved
+ : Layout::State::kLoadedDynamicBlocklistEntries;
+ return sWriteCopyView->mState >= requiredState ? sWriteCopyView : nullptr;
+}
+
+bool SharedSection::Layout::Resolve() {
+ if (mState == State::kResolved) {
+ return true;
+ }
+ if (mState == State::kUninitialized) {
+ return false;
+ }
+ if (mState == State::kInitialized) {
+ if (!mNumBlockEntries) {
+ uintptr_t arrayBase = reinterpret_cast<uintptr_t>(mFirstBlockEntry);
+ uint32_t numEntries = 0;
+ for (DllBlockInfo* entry = mFirstBlockEntry;
+ entry->mName.Length && numEntries < GetMaxNumBlockEntries();
+ ++entry) {
+ entry->mName.Buffer = reinterpret_cast<wchar_t*>(
+ arrayBase + reinterpret_cast<uintptr_t>(entry->mName.Buffer));
+ ++numEntries;
+ }
+ mNumBlockEntries = numEntries;
+ // Sort by name so that we can binary-search
+ std::sort(mFirstBlockEntry, mFirstBlockEntry + mNumBlockEntries,
+ [](const DllBlockInfo& a, const DllBlockInfo& b) {
+ return ::RtlCompareUnicodeString(&a.mName, &b.mName, TRUE) <
+ 0;
+ });
+ }
+ mState = State::kLoadedDynamicBlocklistEntries;
+ }
+
+ if (!mK32Exports.Resolve()) {
+ return false;
+ }
+
+ mState = State::kResolved;
+ return true;
+}
+
+Span<wchar_t> SharedSection::Layout::GetDependentModules() {
+ if (!mDependentModulePathArrayStart) {
+ return nullptr;
+ }
+ return Span<wchar_t>(
+ reinterpret_cast<wchar_t*>(reinterpret_cast<uintptr_t>(this) +
+ mDependentModulePathArrayStart),
+ (kSharedViewSize - mDependentModulePathArrayStart) / sizeof(wchar_t));
+}
+
+bool SharedSection::Layout::IsDisabled() const {
+ return !!mBlocklistIsDisabled;
+}
+
+const DllBlockInfo* SharedSection::Layout::SearchBlocklist(
+ const UNICODE_STRING& aLeafName) const {
+ MOZ_ASSERT(mState >= State::kLoadedDynamicBlocklistEntries);
+ DllBlockInfoComparator comp(aLeafName);
+ size_t match;
+ if (!BinarySearchIf(mFirstBlockEntry, 0, mNumBlockEntries, comp, &match)) {
+ return nullptr;
+ }
+ return &mFirstBlockEntry[match];
+}
+
+Kernel32ExportsSolver* SharedSection::GetKernel32Exports() {
+ Layout* writeCopyView = EnsureWriteCopyView(true);
+ return writeCopyView ? &writeCopyView->mK32Exports : nullptr;
+}
+
+Span<const wchar_t> SharedSection::GetDependentModules() {
+ Layout* writeCopyView = EnsureWriteCopyView();
+ return writeCopyView ? writeCopyView->GetDependentModules() : nullptr;
+}
+
+Span<const DllBlockInfo> SharedSection::GetDynamicBlocklist() {
+ Layout* writeCopyView = EnsureWriteCopyView();
+ return writeCopyView ? writeCopyView->GetModulePathArray() : nullptr;
+}
+
+const DllBlockInfo* SharedSection::SearchBlocklist(
+ const UNICODE_STRING& aLeafName) {
+ Layout* writeCopyView = EnsureWriteCopyView();
+ return writeCopyView ? writeCopyView->SearchBlocklist(aLeafName) : nullptr;
+}
+
+bool SharedSection::IsDisabled() {
+ Layout* writeCopyView = EnsureWriteCopyView();
+ return writeCopyView ? writeCopyView->IsDisabled() : false;
+}
+
+LauncherVoidResult SharedSection::TransferHandle(
+ nt::CrossExecTransferManager& aTransferMgr, DWORD aDesiredAccess,
+ HANDLE* aDestinationAddress) {
+ HANDLE remoteHandle;
+ if (!::DuplicateHandle(nt::kCurrentProcess, sSectionHandle,
+ aTransferMgr.RemoteProcess(), &remoteHandle,
+ aDesiredAccess, FALSE, 0)) {
+ return LAUNCHER_ERROR_FROM_LAST();
+ }
+
+ return aTransferMgr.Transfer(aDestinationAddress, &remoteHandle,
+ sizeof(remoteHandle));
+}
+
+} // namespace freestanding
+} // namespace mozilla