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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
#ifndef mozilla_interceptor_PatcherBase_h
#define mozilla_interceptor_PatcherBase_h
#include "mozilla/interceptor/TargetFunction.h"
namespace mozilla {
namespace interceptor {
template <typename MMPolicy>
struct GetProcAddressSelector;
template <>
struct GetProcAddressSelector<MMPolicyOutOfProcess> {
FARPROC operator()(HMODULE aModule, const char* aName,
const MMPolicyOutOfProcess& aMMPolicy) const {
auto exportSection =
mozilla::nt::PEExportSection<MMPolicyOutOfProcess>::Get(aModule,
aMMPolicy);
return exportSection.GetProcAddress(aName);
}
};
template <>
struct GetProcAddressSelector<MMPolicyInProcess> {
FARPROC operator()(HMODULE aModule, const char* aName,
const MMPolicyInProcess&) const {
// PEExportSection works for MMPolicyInProcess, too, but the native
// GetProcAddress is still better because PEExportSection does not
// solve a forwarded entry.
return ::GetProcAddress(aModule, aName);
}
};
template <typename VMPolicy>
class WindowsDllPatcherBase {
protected:
typedef typename VMPolicy::MMPolicyT MMPolicyT;
template <typename... Args>
explicit WindowsDllPatcherBase(Args&&... aArgs)
: mVMPolicy(std::forward<Args>(aArgs)...) {}
ReadOnlyTargetFunction<MMPolicyT> ResolveRedirectedAddress(
FARPROC aOriginalFunction) {
uintptr_t currAddr = reinterpret_cast<uintptr_t>(aOriginalFunction);
#if defined(_M_IX86) || defined(_M_X64)
uintptr_t prevAddr = 0;
while (prevAddr != currAddr) {
ReadOnlyTargetFunction<MMPolicyT> currFunc(mVMPolicy, currAddr);
prevAddr = currAddr;
// If function entry is jmp rel8 stub to the internal implementation, we
// resolve redirected address from the jump target.
uintptr_t nextAddr = 0;
if (currFunc.IsRelativeShortJump(&nextAddr)) {
int8_t offset = nextAddr - currFunc.GetAddress() - 2;
# if defined(_M_X64)
// We redirect to the target of a short jump backwards if the target
// is another jump (only 32-bit displacement is currently supported).
// This case is used by GetFileAttributesW in Win7 x64.
if ((offset < 0) && (currFunc.IsValidAtOffset(2 + offset))) {
ReadOnlyTargetFunction<MMPolicyT> redirectFn(mVMPolicy, nextAddr);
if (redirectFn.IsIndirectNearJump(&nextAddr)) {
return redirectFn;
}
}
# endif
// We check the downstream has enough nop-space only when the offset is
// positive. Otherwise we stop chasing redirects and let the caller
// fail to hook.
if (offset > 0) {
bool isNopSpace = true;
for (int8_t i = 0; i < offset; i++) {
if (currFunc[2 + i] != 0x90) {
isNopSpace = false;
break;
}
}
if (isNopSpace) {
currAddr = nextAddr;
}
}
# if defined(_M_X64)
} else if (currFunc.IsIndirectNearJump(&nextAddr) ||
currFunc.IsRelativeNearJump(&nextAddr)) {
# else
} else if (currFunc.IsIndirectNearJump(&nextAddr)) {
# endif
// If function entry is jmp [disp32] such as used by kernel32, we
// resolve redirected address from import table. For x64, we resolve
// a relative near jump for TestDllInterceptor with --disable-optimize.
currAddr = nextAddr;
}
}
#endif // defined(_M_IX86) || defined(_M_X64)
if (currAddr != reinterpret_cast<uintptr_t>(aOriginalFunction) &&
!mVMPolicy.IsPageAccessible(currAddr)) {
currAddr = reinterpret_cast<uintptr_t>(aOriginalFunction);
}
return ReadOnlyTargetFunction<MMPolicyT>(mVMPolicy, currAddr);
}
public:
FARPROC GetProcAddress(HMODULE aModule, const char* aName) const {
GetProcAddressSelector<MMPolicyT> selector;
return selector(aModule, aName, mVMPolicy);
}
bool IsPageAccessible(uintptr_t aAddress) const {
return mVMPolicy.IsPageAccessible(aAddress);
}
#if defined(NIGHTLY_BUILD)
const Maybe<DetourError>& GetLastDetourError() const {
return mVMPolicy.GetLastDetourError();
}
#endif // defined(NIGHTLY_BUILD)
template <typename... Args>
void SetLastDetourError(Args&&... aArgs) {
mVMPolicy.SetLastDetourError(std::forward<Args>(aArgs)...);
}
protected:
VMPolicy mVMPolicy;
};
} // namespace interceptor
} // namespace mozilla
#endif // mozilla_interceptor_PatcherBase_h