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Bug 1713735 part 3 - Include rlbox_wasm2c_sandbox repo in the mozilla tree r=glandium

Browse Source 
Differential Revision: https://phabricator.services.mozilla.com/D117386
This commit is contained in:
shravanrn@gmail.com
2021-07-16 02:38:41 +00:00
parent a7d78a1bcb
commit a9d3d86fb9
7 changed files with 906 additions and 0 deletions
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1
config/external/moz.build vendored
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@@ -19,6 +19,7 @@ if CONFIG["MOZ_USING_WASM_SANDBOXING"]:
]
else:
DIRS += [
"rlbox_wasm2c_sandbox",
"wasm2c_sandbox_compiler",
]

13
config/external/rlbox_wasm2c_sandbox/moz.build vendored Normal file
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@@ -0,0 +1,13 @@
# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
# vim: set filetype=python:
# 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 http://mozilla.org/MPL/2.0/.
EXPORTS.mozilla.rlbox += [
"/third_party/rlbox_wasm2c_sandbox/include/rlbox_wasm2c_sandbox.hpp",
]
SOURCES += ["rlbox_wasm2c_thread_locals.cpp"]
FINAL_LIBRARY = "xul"

35
config/external/rlbox_wasm2c_sandbox/moz.yaml vendored Normal file
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@@ -0,0 +1,35 @@
schema: 1
bugzilla:
product: Core
component: "General"
origin:
name: rlbox_wasm2c_sandbox
description: rlbox integration for the wasm2c sandboxed code
url: https://github.com/PLSysSec/rlbox_wasm2c_sandbox
release: commit 3ed74da56a45bc6e556eea60d83995ee2ab962f8 (2021-07-11T21:18:27Z).
revision: 3ed74da56a45bc6e556eea60d83995ee2ab962f8
license: MIT
license-file: LICENSE
vendoring:
url: https://github.com/PLSysSec/rlbox_wasm2c_sandbox.git
source-hosting: github
vendor-directory: third_party/rlbox_wasm2c_sandbox
exclude:
# dirs
- .github
- test
# files
- .clang-format
- .clang-tidy
- .gitignore
- .travis.yml
- AppSandbox.md
- CMakeLists.txt
- LibrarySandbox.md
- README.md

20
config/external/rlbox_wasm2c_sandbox/rlbox_wasm2c_thread_locals.cpp vendored Normal file
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@@ -0,0 +1,20 @@
/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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 http://mozilla.org/MPL/2.0/. */
#ifdef MOZ_USING_WASM_SANDBOXING
// Load general firefox configuration of RLBox
# include "mozilla/rlbox/rlbox_config.h"
# include "mozilla/rlbox/rlbox_wasm2c_sandbox.hpp"
# include "mozilla/rlbox/rlbox.hpp"
// The MingW compiler does not correctly handle static thread_local inline
// members. We instead TLS storage via functions. This can be removed if the
// MingW bug is fixed.
RLBOX_WASM2C_SANDBOX_STATIC_VARIABLES();
#endif

21
third_party/rlbox_wasm2c_sandbox/LICENSE vendored Executable file
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@@ -0,0 +1,21 @@
MIT License
Copyright (c) 2019 UCSD PLSysSec
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

7
third_party/rlbox_wasm2c_sandbox/c_src/wasm2c_sandbox_wrapper.c vendored Executable file
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@@ -0,0 +1,7 @@
#include <stdlib.h>
int main(int argc, char *argv[]) {
(void) argc;
(void) argv;
abort();
}

809
third_party/rlbox_wasm2c_sandbox/include/rlbox_wasm2c_sandbox.hpp vendored Executable file
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@@ -0,0 +1,809 @@
#pragma once
#include "wasm-rt.h"
#include <cstdint>
#include <iostream>
#include <limits>
#include <map>
#include <memory>
#include <mutex>
// RLBox allows applications to provide a custom shared lock implementation
#ifndef RLBOX_USE_CUSTOM_SHARED_LOCK
# include <shared_mutex>
#endif
#include <string>
#include <type_traits>
#include <utility>
#include <vector>
#if defined(_WIN32)
// Ensure the min/max macro in the header doesn't collide with functions in std::
#define NOMINMAX
#include <Windows.h>
#else
#include <dlfcn.h>
#endif
#define RLBOX_WASM2C_UNUSED(...) (void)__VA_ARGS__
// Use the same convention as rlbox to allow applications to customize the
// shared lock
#ifndef RLBOX_USE_CUSTOM_SHARED_LOCK
# define RLBOX_SHARED_LOCK(name) std::shared_timed_mutex name
# define RLBOX_ACQUIRE_SHARED_GUARD(name, ...) \
std::shared_lock<std::shared_timed_mutex> name(__VA_ARGS__)
# define RLBOX_ACQUIRE_UNIQUE_GUARD(name, ...) \
std::unique_lock<std::shared_timed_mutex> name(__VA_ARGS__)
#else
# if !defined(RLBOX_SHARED_LOCK) || !defined(RLBOX_ACQUIRE_SHARED_GUARD) || \
!defined(RLBOX_ACQUIRE_UNIQUE_GUARD)
# error \
"RLBOX_USE_CUSTOM_SHARED_LOCK defined but missing definitions for RLBOX_SHARED_LOCK, RLBOX_ACQUIRE_SHARED_GUARD, RLBOX_ACQUIRE_UNIQUE_GUARD"
# endif
#endif
namespace rlbox {
namespace detail {
// relying on the dynamic check settings (exception vs abort) in the rlbox lib
inline void dynamic_check(bool check, const char* const msg);
}
namespace wasm2c_detail {
template<typename T>
constexpr bool false_v = false;
// https://stackoverflow.com/questions/6512019/can-we-get-the-type-of-a-lambda-argument
namespace return_argument_detail {
template<typename Ret, typename... Rest>
Ret helper(Ret (*)(Rest...));
template<typename Ret, typename F, typename... Rest>
Ret helper(Ret (F::*)(Rest...));
template<typename Ret, typename F, typename... Rest>
Ret helper(Ret (F::*)(Rest...) const);
template<typename F>
decltype(helper(&F::operator())) helper(F);
} // namespace return_argument_detail
template<typename T>
using return_argument =
decltype(return_argument_detail::helper(std::declval<T>()));
///////////////////////////////////////////////////////////////
// https://stackoverflow.com/questions/37602057/why-isnt-a-for-loop-a-compile-time-expression
namespace compile_time_for_detail {
template<std::size_t N>
struct num
{
static const constexpr auto value = N;
};
template<class F, std::size_t... Is>
inline void compile_time_for_helper(F func, std::index_sequence<Is...>)
{
(func(num<Is>{}), ...);
}
} // namespace compile_time_for_detail
template<std::size_t N, typename F>
inline void compile_time_for(F func)
{
compile_time_for_detail::compile_time_for_helper(
func, std::make_index_sequence<N>());
}
///////////////////////////////////////////////////////////////
template<typename T, typename = void>
struct convert_type_to_wasm_type
{
static_assert(std::is_void_v<T>, "Missing specialization");
using type = void;
// wasm2c has no void type so use i32 for now
static constexpr wasm_rt_type_t wasm2c_type = WASM_RT_I32;
};
template<typename T>
struct convert_type_to_wasm_type<
T,
std::enable_if_t<(std::is_integral_v<T> || std::is_enum_v<T>)&&sizeof(T) <=
sizeof(uint32_t)>>
{
using type = uint32_t;
static constexpr wasm_rt_type_t wasm2c_type = WASM_RT_I32;
};
template<typename T>
struct convert_type_to_wasm_type<
T,
std::enable_if_t<(std::is_integral_v<T> ||
std::is_enum_v<T>)&&sizeof(uint32_t) < sizeof(T) &&
sizeof(T) <= sizeof(uint64_t)>>
{
using type = uint64_t;
static constexpr wasm_rt_type_t wasm2c_type = WASM_RT_I64;
};
template<typename T>
struct convert_type_to_wasm_type<T,
std::enable_if_t<std::is_same_v<T, float>>>
{
using type = T;
static constexpr wasm_rt_type_t wasm2c_type = WASM_RT_F32;
};
template<typename T>
struct convert_type_to_wasm_type<T,
std::enable_if_t<std::is_same_v<T, double>>>
{
using type = T;
static constexpr wasm_rt_type_t wasm2c_type = WASM_RT_F64;
};
template<typename T>
struct convert_type_to_wasm_type<
T,
std::enable_if_t<std::is_pointer_v<T> || std::is_class_v<T>>>
{
// pointers are 32 bit indexes in wasm
// class paramters are passed as a pointer to an object in the stack or heap
using type = uint32_t;
static constexpr wasm_rt_type_t wasm2c_type = WASM_RT_I32;
};
///////////////////////////////////////////////////////////////
namespace prepend_arg_type_detail {
template<typename T, typename T_ArgNew>
struct helper;
template<typename T_ArgNew, typename T_Ret, typename... T_Args>
struct helper<T_Ret(T_Args...), T_ArgNew>
{
using type = T_Ret(T_ArgNew, T_Args...);
};
}
template<typename T_Func, typename T_ArgNew>
using prepend_arg_type =
typename prepend_arg_type_detail::helper<T_Func, T_ArgNew>::type;
///////////////////////////////////////////////////////////////
namespace change_return_type_detail {
template<typename T, typename T_RetNew>
struct helper;
template<typename T_RetNew, typename T_Ret, typename... T_Args>
struct helper<T_Ret(T_Args...), T_RetNew>
{
using type = T_RetNew(T_Args...);
};
}
template<typename T_Func, typename T_RetNew>
using change_return_type =
typename change_return_type_detail::helper<T_Func, T_RetNew>::type;
///////////////////////////////////////////////////////////////
namespace change_class_arg_types_detail {
template<typename T, typename T_ArgNew>
struct helper;
template<typename T_ArgNew, typename T_Ret, typename... T_Args>
struct helper<T_Ret(T_Args...), T_ArgNew>
{
using type =
T_Ret(std::conditional_t<std::is_class_v<T_Args>, T_ArgNew, T_Args>...);
};
}
template<typename T_Func, typename T_ArgNew>
using change_class_arg_types =
typename change_class_arg_types_detail::helper<T_Func, T_ArgNew>::type;
} // namespace wasm2c_detail
class rlbox_wasm2c_sandbox;
struct rlbox_wasm2c_sandbox_thread_data
{
rlbox_wasm2c_sandbox* sandbox;
uint32_t last_callback_invoked;
};
#ifdef RLBOX_EMBEDDER_PROVIDES_TLS_STATIC_VARIABLES
rlbox_wasm2c_sandbox_thread_data* get_rlbox_wasm2c_sandbox_thread_data();
# define RLBOX_WASM2C_SANDBOX_STATIC_VARIABLES() \
thread_local rlbox::rlbox_wasm2c_sandbox_thread_data \
rlbox_wasm2c_sandbox_thread_info{ 0, 0 }; \
namespace rlbox { \
rlbox_wasm2c_sandbox_thread_data* get_rlbox_wasm2c_sandbox_thread_data() \
{ \
return &rlbox_wasm2c_sandbox_thread_info; \
} \
} \
static_assert(true, "Enforce semi-colon")
#endif
class rlbox_wasm2c_sandbox
{
public:
using T_LongLongType = int64_t;
using T_LongType = int32_t;
using T_IntType = int32_t;
using T_PointerType = uint32_t;
using T_ShortType = int16_t;
private:
void* sandbox = nullptr;
wasm2c_sandbox_funcs_t sandbox_info;
#if !defined(_MSC_VER)
__attribute__((weak))
#endif
static std::once_flag wasm2c_runtime_initialized;
wasm_rt_memory_t* sandbox_memory_info = nullptr;
void* library = nullptr;
uintptr_t heap_base;
void* exec_env = 0;
void* malloc_index = 0;
void* free_index = 0;
size_t return_slot_size = 0;
T_PointerType return_slot = 0;
static const size_t MAX_CALLBACKS = 128;
mutable RLBOX_SHARED_LOCK(callback_mutex);
void* callback_unique_keys[MAX_CALLBACKS]{ 0 };
void* callbacks[MAX_CALLBACKS]{ 0 };
uint32_t callback_slot_assignment[MAX_CALLBACKS]{ 0 };
mutable std::map<const void*, uint32_t> internal_callbacks;
mutable std::map<uint32_t, const void*> slot_assignments;
#ifndef RLBOX_EMBEDDER_PROVIDES_TLS_STATIC_VARIABLES
thread_local static inline rlbox_wasm2c_sandbox_thread_data thread_data{ 0, 0 };
#endif
template<typename T_FormalRet, typename T_ActualRet>
inline auto serialize_to_sandbox(T_ActualRet arg)
{
if constexpr (std::is_class_v<T_FormalRet>) {
// structs returned as pointers into wasm memory/wasm stack
auto ptr = reinterpret_cast<T_FormalRet*>(
impl_get_unsandboxed_pointer<T_FormalRet*>(arg));
T_FormalRet ret = *ptr;
return ret;
} else {
return arg;
}
}
template<uint32_t N, typename T_Ret, typename... T_Args>
static typename wasm2c_detail::convert_type_to_wasm_type<T_Ret>::type
callback_interceptor(
void* /* vmContext */,
typename wasm2c_detail::convert_type_to_wasm_type<T_Args>::type... params)
{
#ifdef RLBOX_EMBEDDER_PROVIDES_TLS_STATIC_VARIABLES
auto& thread_data = *get_rlbox_wasm2c_sandbox_thread_data();
#endif
thread_data.last_callback_invoked = N;
using T_Func = T_Ret (*)(T_Args...);
T_Func func;
{
RLBOX_ACQUIRE_SHARED_GUARD(lock, thread_data.sandbox->callback_mutex);
func = reinterpret_cast<T_Func>(thread_data.sandbox->callbacks[N]);
}
// Callbacks are invoked through function pointers, cannot use std::forward
// as we don't have caller context for T_Args, which means they are all
// effectively passed by value
return func(thread_data.sandbox->serialize_to_sandbox<T_Args>(params)...);
}
template<uint32_t N, typename T_Ret, typename... T_Args>
static void callback_interceptor_promoted(
void* /* vmContext */,
typename wasm2c_detail::convert_type_to_wasm_type<T_Ret>::type ret,
typename wasm2c_detail::convert_type_to_wasm_type<T_Args>::type... params)
{
#ifdef RLBOX_EMBEDDER_PROVIDES_TLS_STATIC_VARIABLES
auto& thread_data = *get_rlbox_wasm2c_sandbox_thread_data();
#endif
thread_data.last_callback_invoked = N;
using T_Func = T_Ret (*)(T_Args...);
T_Func func;
{
RLBOX_ACQUIRE_SHARED_GUARD(lock, thread_data.sandbox->callback_mutex);
func = reinterpret_cast<T_Func>(thread_data.sandbox->callbacks[N]);
}
// Callbacks are invoked through function pointers, cannot use std::forward
// as we don't have caller context for T_Args, which means they are all
// effectively passed by value
auto ret_val =
func(thread_data.sandbox->serialize_to_sandbox<T_Args>(params)...);
// Copy the return value back
auto ret_ptr = reinterpret_cast<T_Ret*>(
thread_data.sandbox->template impl_get_unsandboxed_pointer<T_Ret*>(ret));
*ret_ptr = ret_val;
}
template<typename T_Ret, typename... T_Args>
inline uint32_t get_wasm2c_func_index(
// dummy for template inference
T_Ret (*)(T_Args...) = nullptr
) const
{
// Class return types as promoted to args
constexpr bool promoted = std::is_class_v<T_Ret>;
// If return type is void, then there is no return type
// But it is fine if we add it anyway as it as at the end of the array
// and we pass in counts to lookup_wasm2c_func_index that would result in this
// element not being accessed
wasm_rt_type_t ret_param_types[] = {
wasm2c_detail::convert_type_to_wasm_type<T_Args>::wasm2c_type...,
wasm2c_detail::convert_type_to_wasm_type<T_Ret>::wasm2c_type
};
uint32_t param_count = 0;
uint32_t ret_count = 0;
if constexpr (promoted) {
param_count = sizeof...(T_Args) + 1;
ret_count = 0;
} else {
param_count = sizeof...(T_Args);
ret_count = std::is_void_v<T_Ret>? 0 : 1;
}
auto ret = sandbox_info.lookup_wasm2c_func_index(sandbox, param_count, ret_count, ret_param_types);
return ret;
}
void ensure_return_slot_size(size_t size)
{
if (size > return_slot_size) {
if (return_slot_size) {
impl_free_in_sandbox(return_slot);
}
return_slot = impl_malloc_in_sandbox(size);
detail::dynamic_check(
return_slot != 0,
"Error initializing return slot. Sandbox may be out of memory!");
return_slot_size = size;
}
}
inline void* symbol_lookup(std::string prefixed_name) {
#if defined(_WIN32)
void* ret = GetProcAddress((HMODULE) library, prefixed_name.c_str());
#else
void* ret = dlsym(library, prefixed_name.c_str());
#endif
return ret;
}
protected:
inline void impl_create_sandbox(const char* wasm2c_module_path, const char* wasm_module_name = "")
{
detail::dynamic_check(sandbox == nullptr, "Sandbox already initialized");
#if defined(_WIN32)
library = LoadLibraryA(wasm2c_module_path);
#else
library = dlopen(wasm2c_module_path, RTLD_LAZY);
#endif
if (!library) {
std::string error_msg = "Could not load wasm2c dynamic library: ";
#if defined(_WIN32)
DWORD errorMessageID = GetLastError();
if (errorMessageID != 0) {
LPSTR messageBuffer = nullptr;
//The api creates the buffer that holds the message
size_t size = FormatMessageA(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
NULL, errorMessageID, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), (LPSTR)&messageBuffer, 0, NULL);
//Copy the error message into a std::string.
std::string message(messageBuffer, size);
error_msg += message;
LocalFree(messageBuffer);
}
#else
error_msg += dlerror();
#endif
detail::dynamic_check(false, error_msg.c_str());
}
std::string info_func_name = wasm_module_name;
info_func_name += "get_wasm2c_sandbox_info";
auto get_info_func = reinterpret_cast<wasm2c_sandbox_funcs_t(*)()>(symbol_lookup(info_func_name));
detail::dynamic_check(get_info_func != nullptr, "wasm2c could not find <MODULE_NAME>get_wasm2c_sandbox_info");
sandbox_info = get_info_func();
std::call_once(wasm2c_runtime_initialized, [&](){
sandbox_info.wasm_rt_sys_init();
});
sandbox = sandbox_info.create_wasm2c_sandbox();
detail::dynamic_check(sandbox != nullptr, "Sandbox could not be created");
sandbox_memory_info = (wasm_rt_memory_t*) sandbox_info.lookup_wasm2c_nonfunc_export(sandbox, "memory");
detail::dynamic_check(sandbox_memory_info != nullptr, "Could not get wasm2c sandbox memory info");
heap_base = reinterpret_cast<uintptr_t>(impl_get_memory_location());
// Check that the address space is larger than the sandbox heap i.e. 4GB
// sandbox heap, host has to have more than 4GB
static_assert(sizeof(uintptr_t) > sizeof(T_PointerType));
// Check that the heap is aligned to the pointer size i.e. 32-bit pointer =>
// aligned to 4GB. The implementations of
// impl_get_unsandboxed_pointer_no_ctx and impl_get_sandboxed_pointer_no_ctx
// below rely on this.
uintptr_t heap_offset_mask = std::numeric_limits<T_PointerType>::max();
detail::dynamic_check((heap_base & heap_offset_mask) == 0,
"Sandbox heap not aligned to 4GB");
// cache these for performance
exec_env = sandbox;
malloc_index = impl_lookup_symbol("malloc");
free_index = impl_lookup_symbol("free");
}
inline void impl_destroy_sandbox()
{
if (return_slot_size) {
impl_free_in_sandbox(return_slot);
}
sandbox_info.destroy_wasm2c_sandbox(sandbox);
sandbox = nullptr;
#if defined(_WIN32)
FreeLibrary((HMODULE) library);
#else
dlclose(library);
#endif
library = nullptr;
}
template<typename T>
inline void* impl_get_unsandboxed_pointer(T_PointerType p) const
{
if constexpr (std::is_function_v<std::remove_pointer_t<T>>) {
RLBOX_ACQUIRE_UNIQUE_GUARD(lock, callback_mutex);
auto found = slot_assignments.find(p);
if (found != slot_assignments.end()) {
auto ret = found->second;
return const_cast<void*>(ret);
} else {
return nullptr;
}
} else {
return reinterpret_cast<void*>(heap_base + p);
}
}
template<typename T>
inline T_PointerType impl_get_sandboxed_pointer(const void* p) const
{
if constexpr (std::is_function_v<std::remove_pointer_t<T>>) {
RLBOX_ACQUIRE_UNIQUE_GUARD(lock, callback_mutex);
uint32_t slot_number = 0;
auto found = internal_callbacks.find(p);
if (found != internal_callbacks.end()) {
slot_number = found->second;
} else {
auto func_type_idx = get_wasm2c_func_index(static_cast<T>(nullptr));
slot_number =
sandbox_info.add_wasm2c_callback(sandbox, func_type_idx, const_cast<void*>(p));
internal_callbacks[p] = slot_number;
slot_assignments[slot_number] = p;
}
return static_cast<T_PointerType>(slot_number);
} else {
return static_cast<T_PointerType>(reinterpret_cast<uintptr_t>(p));
}
}
template<typename T>
static inline void* impl_get_unsandboxed_pointer_no_ctx(
T_PointerType p,
const void* example_unsandboxed_ptr,
rlbox_wasm2c_sandbox* (*expensive_sandbox_finder)(
const void* example_unsandboxed_ptr))
{
if constexpr (std::is_function_v<std::remove_pointer_t<T>>) {
// swizzling function pointers needs access to the function pointer tables
// and thus cannot be done without context
auto sandbox = expensive_sandbox_finder(example_unsandboxed_ptr);
return sandbox->impl_get_unsandboxed_pointer<T>(p);
} else {
// grab the memory base from the example_unsandboxed_ptr
uintptr_t heap_base_mask =
std::numeric_limits<uintptr_t>::max() &
~(static_cast<uintptr_t>(std::numeric_limits<T_PointerType>::max()));
uintptr_t computed_heap_base =
reinterpret_cast<uintptr_t>(example_unsandboxed_ptr) & heap_base_mask;
uintptr_t ret = computed_heap_base | p;
return reinterpret_cast<void*>(ret);
}
}
template<typename T>
static inline T_PointerType impl_get_sandboxed_pointer_no_ctx(
const void* p,
const void* example_unsandboxed_ptr,
rlbox_wasm2c_sandbox* (*expensive_sandbox_finder)(
const void* example_unsandboxed_ptr))
{
if constexpr (std::is_function_v<std::remove_pointer_t<T>>) {
// swizzling function pointers needs access to the function pointer tables
// and thus cannot be done without context
auto sandbox = expensive_sandbox_finder(example_unsandboxed_ptr);
return sandbox->impl_get_sandboxed_pointer<T>(p);
} else {
// Just clear the memory base to leave the offset
RLBOX_WASM2C_UNUSED(example_unsandboxed_ptr);
uintptr_t ret = reinterpret_cast<uintptr_t>(p) &
std::numeric_limits<T_PointerType>::max();
return static_cast<T_PointerType>(ret);
}
}
static inline bool impl_is_in_same_sandbox(const void* p1, const void* p2)
{
uintptr_t heap_base_mask = std::numeric_limits<uintptr_t>::max() &
~(std::numeric_limits<T_PointerType>::max());
return (reinterpret_cast<uintptr_t>(p1) & heap_base_mask) ==
(reinterpret_cast<uintptr_t>(p2) & heap_base_mask);
}
inline bool impl_is_pointer_in_sandbox_memory(const void* p)
{
size_t length = impl_get_total_memory();
uintptr_t p_val = reinterpret_cast<uintptr_t>(p);
return p_val >= heap_base && p_val < (heap_base + length);
}
inline bool impl_is_pointer_in_app_memory(const void* p)
{
return !(impl_is_pointer_in_sandbox_memory(p));
}
inline size_t impl_get_total_memory() { return sandbox_memory_info->size; }
inline void* impl_get_memory_location()
{
return sandbox_memory_info->data;
}
void* impl_lookup_symbol(const char* func_name)
{
std::string prefixed_name = "w2c_";
prefixed_name += func_name;
void* ret = symbol_lookup(prefixed_name);
return ret;
}
template<typename T, typename T_Converted, typename... T_Args>
auto impl_invoke_with_func_ptr(T_Converted* func_ptr, T_Args&&... params)
{
#ifdef RLBOX_EMBEDDER_PROVIDES_TLS_STATIC_VARIABLES
auto& thread_data = *get_rlbox_wasm2c_sandbox_thread_data();
#endif
thread_data.sandbox = this;
// WASM functions are mangled in the following manner
// 1. All primitive types are left as is and follow an LP32 machine model
// (as opposed to the possibly 64-bit application)
// 2. All pointers are changed to u32 types
// 3. Returned class are returned as an out parameter before the actual
// function parameters
// 4. All class parameters are passed as pointers (u32 types)
// 5. The heap address is passed in as the first argument to the function
//
// RLBox accounts for the first 2 differences in T_Converted type, but we
// need to handle the rest
// Handle point 3
using T_Ret = wasm2c_detail::return_argument<T_Converted>;
if constexpr (std::is_class_v<T_Ret>) {
using T_Conv1 = wasm2c_detail::change_return_type<T_Converted, void>;
using T_Conv2 = wasm2c_detail::prepend_arg_type<T_Conv1, T_PointerType>;
auto func_ptr_conv =
reinterpret_cast<T_Conv2*>(reinterpret_cast<uintptr_t>(func_ptr));
ensure_return_slot_size(sizeof(T_Ret));
impl_invoke_with_func_ptr<T>(func_ptr_conv, return_slot, params...);
auto ptr = reinterpret_cast<T_Ret*>(
impl_get_unsandboxed_pointer<T_Ret*>(return_slot));
T_Ret ret = *ptr;
return ret;
}
// Handle point 4
constexpr size_t alloc_length = [&] {
if constexpr (sizeof...(params) > 0) {
return ((std::is_class_v<T_Args> ? 1 : 0) + ...);
} else {
return 0;
}
}();
// 0 arg functions create 0 length arrays which is not allowed
T_PointerType allocations_buff[alloc_length == 0 ? 1 : alloc_length];
T_PointerType* allocations = allocations_buff;
auto serialize_class_arg =
[&](auto arg) -> std::conditional_t<std::is_class_v<decltype(arg)>,
T_PointerType,
decltype(arg)> {
using T_Arg = decltype(arg);
if constexpr (std::is_class_v<T_Arg>) {
auto slot = impl_malloc_in_sandbox(sizeof(T_Arg));
auto ptr =
reinterpret_cast<T_Arg*>(impl_get_unsandboxed_pointer<T_Arg*>(slot));
*ptr = arg;
allocations[0] = slot;
allocations++;
return slot;
} else {
return arg;
}
};
// 0 arg functions don't use serialize
RLBOX_WASM2C_UNUSED(serialize_class_arg);
using T_ConvNoClass =
wasm2c_detail::change_class_arg_types<T_Converted, T_PointerType>;
// Handle Point 5
using T_ConvHeap = wasm2c_detail::prepend_arg_type<T_ConvNoClass, void*>;
// Function invocation
auto func_ptr_conv =
reinterpret_cast<T_ConvHeap*>(reinterpret_cast<uintptr_t>(func_ptr));
using T_NoVoidRet =
std::conditional_t<std::is_void_v<T_Ret>, uint32_t, T_Ret>;
T_NoVoidRet ret;
if constexpr (std::is_void_v<T_Ret>) {
RLBOX_WASM2C_UNUSED(ret);
func_ptr_conv(exec_env, serialize_class_arg(params)...);
} else {
ret = func_ptr_conv(exec_env, serialize_class_arg(params)...);
}
for (size_t i = 0; i < alloc_length; i++) {
impl_free_in_sandbox(allocations_buff[i]);
}
if constexpr (!std::is_void_v<T_Ret>) {
return ret;
}
}
inline T_PointerType impl_malloc_in_sandbox(size_t size)
{
detail::dynamic_check(size <= std::numeric_limits<uint32_t>::max(),
"Attempting to malloc more than the heap size");
using T_Func = void*(size_t);
using T_Converted = T_PointerType(uint32_t);
T_PointerType ret = impl_invoke_with_func_ptr<T_Func, T_Converted>(
reinterpret_cast<T_Converted*>(malloc_index),
static_cast<uint32_t>(size));
return ret;
}
inline void impl_free_in_sandbox(T_PointerType p)
{
using T_Func = void(void*);
using T_Converted = void(T_PointerType);
impl_invoke_with_func_ptr<T_Func, T_Converted>(
reinterpret_cast<T_Converted*>(free_index), p);
}
template<typename T_Ret, typename... T_Args>
inline T_PointerType impl_register_callback(void* key, void* callback)
{
bool found = false;
uint32_t found_loc = 0;
void* chosen_interceptor = nullptr;
RLBOX_ACQUIRE_UNIQUE_GUARD(lock, callback_mutex);
// need a compile time for loop as we we need I to be a compile time value
// this is because we are setting the I'th callback ineterceptor
wasm2c_detail::compile_time_for<MAX_CALLBACKS>([&](auto I) {
constexpr auto i = I.value;
if (!found && callbacks[i] == nullptr) {
found = true;
found_loc = i;
if constexpr (std::is_class_v<T_Ret>) {
chosen_interceptor = reinterpret_cast<void*>(
callback_interceptor_promoted<i, T_Ret, T_Args...>);
} else {
chosen_interceptor =
reinterpret_cast<void*>(callback_interceptor<i, T_Ret, T_Args...>);
}
}
});
detail::dynamic_check(
found,
"Could not find an empty slot in sandbox function table. This would "
"happen if you have registered too many callbacks, or unsandboxed "
"too many function pointers. You can file a bug if you want to "
"increase the maximum allowed callbacks or unsadnboxed functions "
"pointers");
auto func_type_idx = get_wasm2c_func_index<T_Ret, T_Args...>();
uint32_t slot_number =
sandbox_info.add_wasm2c_callback(sandbox, func_type_idx, chosen_interceptor);
callback_unique_keys[found_loc] = key;
callbacks[found_loc] = callback;
callback_slot_assignment[found_loc] = slot_number;
slot_assignments[slot_number] = callback;
return static_cast<T_PointerType>(slot_number);
}
static inline std::pair<rlbox_wasm2c_sandbox*, void*>
impl_get_executed_callback_sandbox_and_key()
{
#ifdef RLBOX_EMBEDDER_PROVIDES_TLS_STATIC_VARIABLES
auto& thread_data = *get_rlbox_wasm2c_sandbox_thread_data();
#endif
auto sandbox = thread_data.sandbox;
auto callback_num = thread_data.last_callback_invoked;
void* key = sandbox->callback_unique_keys[callback_num];
return std::make_pair(sandbox, key);
}
template<typename T_Ret, typename... T_Args>
inline void impl_unregister_callback(void* key)
{
bool found = false;
uint32_t i = 0;
{
RLBOX_ACQUIRE_UNIQUE_GUARD(lock, callback_mutex);
for (; i < MAX_CALLBACKS; i++) {
if (callback_unique_keys[i] == key) {
sandbox_info.remove_wasm2c_callback(sandbox, callback_slot_assignment[i]);
callback_unique_keys[i] = nullptr;
callbacks[i] = nullptr;
callback_slot_assignment[i] = 0;
found = true;
break;
}
}
}
detail::dynamic_check(
found, "Internal error: Could not find callback to unregister");
return;
}
};
// declare the static symbol with weak linkage to keep this header only
#if defined(_MSC_VER)
__declspec(selectany)
#else
__attribute__((weak))
#endif
std::once_flag rlbox_wasm2c_sandbox::wasm2c_runtime_initialized;
} // namespace rlbox