chromium/third_party/crashpad/crashpad/util/misc/no_cfi_icall.h

// Copyright 2020 The Crashpad Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef CRASHPAD_UTIL_MISC_NO_CFI_ICALL_H_
#define CRASHPAD_UTIL_MISC_NO_CFI_ICALL_H_

#include <type_traits>
#include <utility>

#include "base/compiler_specific.h"
#include "build/build_config.h"

#if BUILDFLAG(IS_WIN)
#include <windows.h>
#endif  // BUILDFLAG(IS_WIN)

namespace crashpad {

namespace {

template <typename Functor>
struct FunctorTraits;

FunctorTraits<R (*)(Args...) noexcept>;

FunctorTraits<R (*)(Args..., ...) noexcept>;

#if BUILDFLAG(IS_WIN) && defined(ARCH_CPU_X86)
template <typename R, typename... Args>
struct FunctorTraits<R(__stdcall*)(Args...) noexcept> {
  template <typename... RunArgs>
  DISABLE_CFI_ICALL static R Invoke(R(__stdcall* function)(Args...),
                                    RunArgs&&... args) {
    return function(std::forward<RunArgs>(args)...);
  }
};
#endif  // BUILDFLAG(IS_WIN) && ARCH_CPU_X86

#if __cplusplus >= 201703L
// These specializations match functions which are not explicitly declared
// noexcept. They must only be present at C++17 when noexcept is part of a
// function's type. If they are present earlier, they redefine the
// specializations above.
FunctorTraits<R (*)(Args...)>;

FunctorTraits<R (*)(Args..., ...)>;

#if BUILDFLAG(IS_WIN) && defined(ARCH_CPU_X86)
template <typename R, typename... Args>
struct FunctorTraits<R(__stdcall*)(Args...)> {
  template <typename... RunArgs>
  DISABLE_CFI_ICALL static R Invoke(R(__stdcall* function)(Args...),
                                    RunArgs&&... args) {
    return function(std::forward<RunArgs>(args)...);
  }
};
#endif  // BUILDFLAG(IS_WIN) && ARCH_CPU_X86

#endif  // __cplusplus >= 201703L

}  // namespace

//! \brief Disables cfi-icall for calls made through a function pointer.
//!
//! Clang provides several Control-Flow-Integrity (CFI) sanitizers, among them,
//! cfi-icall, which attempts to verify that the dynamic type of a function
//! matches the static type of the function pointer used to call it.
//!
//! https://clang.llvm.org/docs/ControlFlowIntegrity.html#indirect-function-call-checking
//!
//! However, cfi-icall does not have enough information to check indirect calls
//! to functions in other modules, such as through the pointers returned by
//! `dlsym()`. In these cases, CFI aborts the program upon executing the
//! indirect call.
//!
//! This class encapsulates cross-DSO function pointers to disable cfi-icall
//! precisely when calling these pointers.
template <typename Functor>
class NoCfiIcall { … };

}  // namespace crashpad

#endif  // CRASHPAD_UTIL_MISC_NO_CFI_ICALL_H_