| // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "sandbox/win/src/process_mitigations.h" |
| |
| #include <stddef.h> |
| |
| #include <algorithm> |
| |
| #include "base/win/windows_version.h" |
| #include "sandbox/win/src/nt_internals.h" |
| #include "sandbox/win/src/restricted_token_utils.h" |
| #include "sandbox/win/src/sandbox_rand.h" |
| #include "sandbox/win/src/win_utils.h" |
| |
| namespace { |
| |
| // Functions for enabling policies. |
| typedef BOOL (WINAPI *SetProcessDEPPolicyFunction)(DWORD dwFlags); |
| |
| typedef BOOL (WINAPI *SetProcessMitigationPolicyFunction)( |
| PROCESS_MITIGATION_POLICY mitigation_policy, |
| PVOID buffer, |
| SIZE_T length); |
| |
| typedef BOOL (WINAPI *SetDefaultDllDirectoriesFunction)( |
| DWORD DirectoryFlags); |
| |
| } // namespace |
| |
| namespace sandbox { |
| |
| bool ApplyProcessMitigationsToCurrentProcess(MitigationFlags flags) { |
| if (!CanSetProcessMitigationsPostStartup(flags)) |
| return false; |
| |
| base::win::Version version = base::win::GetVersion(); |
| HMODULE module = ::GetModuleHandleA("kernel32.dll"); |
| |
| if (version >= base::win::VERSION_VISTA && |
| (flags & MITIGATION_DLL_SEARCH_ORDER)) { |
| SetDefaultDllDirectoriesFunction set_default_dll_directories = |
| reinterpret_cast<SetDefaultDllDirectoriesFunction>( |
| ::GetProcAddress(module, "SetDefaultDllDirectories")); |
| |
| // Check for SetDefaultDllDirectories since it requires KB2533623. |
| if (set_default_dll_directories) { |
| if (!set_default_dll_directories(LOAD_LIBRARY_SEARCH_DEFAULT_DIRS) && |
| ERROR_ACCESS_DENIED != ::GetLastError()) { |
| return false; |
| } |
| } |
| } |
| |
| // Set the heap to terminate on corruption |
| if (version >= base::win::VERSION_VISTA && |
| (flags & MITIGATION_HEAP_TERMINATE)) { |
| if (!::HeapSetInformation(NULL, HeapEnableTerminationOnCorruption, |
| NULL, 0) && |
| ERROR_ACCESS_DENIED != ::GetLastError()) { |
| return false; |
| } |
| } |
| |
| if (version >= base::win::VERSION_WIN7 && |
| (flags & MITIGATION_HARDEN_TOKEN_IL_POLICY)) { |
| DWORD error = HardenProcessIntegrityLevelPolicy(); |
| if ((error != ERROR_SUCCESS) && (error != ERROR_ACCESS_DENIED)) |
| return false; |
| } |
| |
| #if !defined(_WIN64) // DEP is always enabled on 64-bit. |
| if (flags & MITIGATION_DEP) { |
| DWORD dep_flags = PROCESS_DEP_ENABLE; |
| // DEP support is quirky on XP, so don't force a failure in that case. |
| const bool return_on_fail = version >= base::win::VERSION_VISTA; |
| |
| if (flags & MITIGATION_DEP_NO_ATL_THUNK) |
| dep_flags |= PROCESS_DEP_DISABLE_ATL_THUNK_EMULATION; |
| |
| SetProcessDEPPolicyFunction set_process_dep_policy = |
| reinterpret_cast<SetProcessDEPPolicyFunction>( |
| ::GetProcAddress(module, "SetProcessDEPPolicy")); |
| if (set_process_dep_policy) { |
| if (!set_process_dep_policy(dep_flags) && |
| ERROR_ACCESS_DENIED != ::GetLastError() && return_on_fail) { |
| return false; |
| } |
| } else { |
| // We're on XP sp2, so use the less standard approach. |
| // For reference: http://www.uninformed.org/?v=2&a=4 |
| static const int MEM_EXECUTE_OPTION_DISABLE = 2; |
| static const int MEM_EXECUTE_OPTION_ATL7_THUNK_EMULATION = 4; |
| static const int MEM_EXECUTE_OPTION_PERMANENT = 8; |
| |
| NtSetInformationProcessFunction set_information_process = NULL; |
| ResolveNTFunctionPtr("NtSetInformationProcess", |
| &set_information_process); |
| if (!set_information_process) |
| return false; |
| ULONG dep = MEM_EXECUTE_OPTION_DISABLE | MEM_EXECUTE_OPTION_PERMANENT; |
| if (!(dep_flags & PROCESS_DEP_DISABLE_ATL_THUNK_EMULATION)) |
| dep |= MEM_EXECUTE_OPTION_ATL7_THUNK_EMULATION; |
| if (!SUCCEEDED(set_information_process(GetCurrentProcess(), |
| ProcessExecuteFlags, |
| &dep, sizeof(dep))) && |
| ERROR_ACCESS_DENIED != ::GetLastError() && return_on_fail) { |
| return false; |
| } |
| } |
| } |
| #endif |
| |
| // This is all we can do in Win7 and below. |
| if (version < base::win::VERSION_WIN8) |
| return true; |
| |
| SetProcessMitigationPolicyFunction set_process_mitigation_policy = |
| reinterpret_cast<SetProcessMitigationPolicyFunction>( |
| ::GetProcAddress(module, "SetProcessMitigationPolicy")); |
| if (!set_process_mitigation_policy) |
| return false; |
| |
| // Enable ASLR policies. |
| if (flags & MITIGATION_RELOCATE_IMAGE) { |
| PROCESS_MITIGATION_ASLR_POLICY policy = {}; |
| policy.EnableForceRelocateImages = true; |
| policy.DisallowStrippedImages = (flags & |
| MITIGATION_RELOCATE_IMAGE_REQUIRED) == |
| MITIGATION_RELOCATE_IMAGE_REQUIRED; |
| |
| if (!set_process_mitigation_policy(ProcessASLRPolicy, &policy, |
| sizeof(policy)) && |
| ERROR_ACCESS_DENIED != ::GetLastError()) { |
| return false; |
| } |
| } |
| |
| // Enable strict handle policies. |
| if (flags & MITIGATION_STRICT_HANDLE_CHECKS) { |
| PROCESS_MITIGATION_STRICT_HANDLE_CHECK_POLICY policy = {}; |
| policy.HandleExceptionsPermanentlyEnabled = |
| policy.RaiseExceptionOnInvalidHandleReference = true; |
| |
| if (!set_process_mitigation_policy(ProcessStrictHandleCheckPolicy, &policy, |
| sizeof(policy)) && |
| ERROR_ACCESS_DENIED != ::GetLastError()) { |
| return false; |
| } |
| } |
| |
| // Enable system call policies. |
| if (flags & MITIGATION_WIN32K_DISABLE) { |
| PROCESS_MITIGATION_SYSTEM_CALL_DISABLE_POLICY policy = {}; |
| policy.DisallowWin32kSystemCalls = true; |
| |
| if (!set_process_mitigation_policy(ProcessSystemCallDisablePolicy, &policy, |
| sizeof(policy)) && |
| ERROR_ACCESS_DENIED != ::GetLastError()) { |
| return false; |
| } |
| } |
| |
| // Enable dll extension policies. |
| if (flags & MITIGATION_EXTENSION_DLL_DISABLE) { |
| PROCESS_MITIGATION_EXTENSION_POINT_DISABLE_POLICY policy = {}; |
| policy.DisableExtensionPoints = true; |
| |
| if (!set_process_mitigation_policy(ProcessExtensionPointDisablePolicy, |
| &policy, sizeof(policy)) && |
| ERROR_ACCESS_DENIED != ::GetLastError()) { |
| return false; |
| } |
| } |
| |
| if (version < base::win::VERSION_WIN10) |
| return true; |
| |
| // Enable font policies. |
| if (flags & MITIGATION_NONSYSTEM_FONT_DISABLE) { |
| PROCESS_MITIGATION_FONT_DISABLE_POLICY policy = {0}; |
| policy.DisableNonSystemFonts = true; |
| |
| if (!set_process_mitigation_policy(ProcessFontDisablePolicy, &policy, |
| sizeof(policy)) && |
| ERROR_ACCESS_DENIED != ::GetLastError()) { |
| return false; |
| } |
| } |
| |
| if (version < base::win::VERSION_WIN10_TH2) |
| return true; |
| |
| // Enable image load policies. |
| if (flags & MITIGATION_IMAGE_LOAD_NO_REMOTE || |
| flags & MITIGATION_IMAGE_LOAD_NO_LOW_LABEL) { |
| PROCESS_MITIGATION_IMAGE_LOAD_POLICY policy = {0}; |
| if (flags & MITIGATION_IMAGE_LOAD_NO_REMOTE) |
| policy.NoRemoteImages = true; |
| if (flags & MITIGATION_IMAGE_LOAD_NO_LOW_LABEL) |
| policy.NoLowMandatoryLabelImages = true; |
| |
| if (!set_process_mitigation_policy(ProcessImageLoadPolicy, &policy, |
| sizeof(policy)) && |
| ERROR_ACCESS_DENIED != ::GetLastError()) { |
| return false; |
| } |
| } |
| |
| return true; |
| } |
| |
| void ConvertProcessMitigationsToPolicy(MitigationFlags flags, |
| DWORD64* policy_flags, |
| size_t* size) { |
| base::win::Version version = base::win::GetVersion(); |
| |
| *policy_flags = 0; |
| #if defined(_WIN64) |
| *size = sizeof(*policy_flags); |
| #elif defined(_M_IX86) |
| // A 64-bit flags attribute is illegal on 32-bit Win 7 and below. |
| if (version < base::win::VERSION_WIN8) |
| *size = sizeof(DWORD); |
| else |
| *size = sizeof(*policy_flags); |
| #else |
| #error This platform is not supported. |
| #endif |
| |
| // Nothing for Win XP or Vista. |
| if (version <= base::win::VERSION_VISTA) |
| return; |
| |
| // DEP and SEHOP are not valid for 64-bit Windows |
| #if !defined(_WIN64) |
| if (flags & MITIGATION_DEP) { |
| *policy_flags |= PROCESS_CREATION_MITIGATION_POLICY_DEP_ENABLE; |
| if (!(flags & MITIGATION_DEP_NO_ATL_THUNK)) |
| *policy_flags |= PROCESS_CREATION_MITIGATION_POLICY_DEP_ATL_THUNK_ENABLE; |
| } |
| |
| if (flags & MITIGATION_SEHOP) |
| *policy_flags |= PROCESS_CREATION_MITIGATION_POLICY_SEHOP_ENABLE; |
| #endif |
| |
| // Win 7 |
| if (version < base::win::VERSION_WIN8) |
| return; |
| |
| if (flags & MITIGATION_RELOCATE_IMAGE) { |
| *policy_flags |= |
| PROCESS_CREATION_MITIGATION_POLICY_FORCE_RELOCATE_IMAGES_ALWAYS_ON; |
| if (flags & MITIGATION_RELOCATE_IMAGE_REQUIRED) { |
| *policy_flags |= |
| PROCESS_CREATION_MITIGATION_POLICY_FORCE_RELOCATE_IMAGES_ALWAYS_ON_REQ_RELOCS; |
| } |
| } |
| |
| if (flags & MITIGATION_HEAP_TERMINATE) { |
| *policy_flags |= |
| PROCESS_CREATION_MITIGATION_POLICY_HEAP_TERMINATE_ALWAYS_ON; |
| } |
| |
| if (flags & MITIGATION_BOTTOM_UP_ASLR) { |
| *policy_flags |= |
| PROCESS_CREATION_MITIGATION_POLICY_BOTTOM_UP_ASLR_ALWAYS_ON; |
| } |
| |
| if (flags & MITIGATION_HIGH_ENTROPY_ASLR) { |
| *policy_flags |= |
| PROCESS_CREATION_MITIGATION_POLICY_HIGH_ENTROPY_ASLR_ALWAYS_ON; |
| } |
| |
| if (flags & MITIGATION_STRICT_HANDLE_CHECKS) { |
| *policy_flags |= |
| PROCESS_CREATION_MITIGATION_POLICY_STRICT_HANDLE_CHECKS_ALWAYS_ON; |
| } |
| |
| if (flags & MITIGATION_WIN32K_DISABLE) { |
| *policy_flags |= |
| PROCESS_CREATION_MITIGATION_POLICY_WIN32K_SYSTEM_CALL_DISABLE_ALWAYS_ON; |
| } |
| |
| if (flags & MITIGATION_EXTENSION_DLL_DISABLE) { |
| *policy_flags |= |
| PROCESS_CREATION_MITIGATION_POLICY_EXTENSION_POINT_DISABLE_ALWAYS_ON; |
| } |
| |
| if (version < base::win::VERSION_WIN10) |
| return; |
| |
| if (flags & MITIGATION_NONSYSTEM_FONT_DISABLE) { |
| *policy_flags |= PROCESS_CREATION_MITIGATION_POLICY_FONT_DISABLE_ALWAYS_ON; |
| } |
| |
| if (version < base::win::VERSION_WIN10_TH2) |
| return; |
| |
| if (flags & MITIGATION_IMAGE_LOAD_NO_REMOTE) { |
| *policy_flags |= |
| PROCESS_CREATION_MITIGATION_POLICY_IMAGE_LOAD_NO_REMOTE_ALWAYS_ON; |
| } |
| |
| if (flags & MITIGATION_IMAGE_LOAD_NO_LOW_LABEL) { |
| *policy_flags |= |
| PROCESS_CREATION_MITIGATION_POLICY_IMAGE_LOAD_NO_LOW_LABEL_ALWAYS_ON; |
| } |
| } |
| |
| MitigationFlags FilterPostStartupProcessMitigations(MitigationFlags flags) { |
| base::win::Version version = base::win::GetVersion(); |
| |
| // Windows XP SP2+. |
| if (version < base::win::VERSION_VISTA) { |
| return flags & (MITIGATION_DEP | |
| MITIGATION_DEP_NO_ATL_THUNK); |
| } |
| |
| // Windows Vista |
| if (version < base::win::VERSION_WIN7) { |
| return flags & (MITIGATION_BOTTOM_UP_ASLR | |
| MITIGATION_DLL_SEARCH_ORDER | |
| MITIGATION_HEAP_TERMINATE); |
| } |
| |
| // Windows 7. |
| if (version < base::win::VERSION_WIN8) { |
| return flags & (MITIGATION_BOTTOM_UP_ASLR | |
| MITIGATION_DLL_SEARCH_ORDER | |
| MITIGATION_HEAP_TERMINATE); |
| } |
| |
| // Windows 8 and above. |
| return flags & (MITIGATION_BOTTOM_UP_ASLR | |
| MITIGATION_DLL_SEARCH_ORDER); |
| } |
| |
| bool ApplyProcessMitigationsToSuspendedProcess(HANDLE process, |
| MitigationFlags flags) { |
| // This is a hack to fake a weak bottom-up ASLR on 32-bit Windows. |
| #if !defined(_WIN64) |
| if (flags & MITIGATION_BOTTOM_UP_ASLR) { |
| unsigned int limit; |
| GetRandom(&limit); |
| char* ptr = 0; |
| const size_t kMask64k = 0xFFFF; |
| // Random range (512k-16.5mb) in 64k steps. |
| const char* end = ptr + ((((limit % 16384) + 512) * 1024) & ~kMask64k); |
| while (ptr < end) { |
| MEMORY_BASIC_INFORMATION memory_info; |
| if (!::VirtualQueryEx(process, ptr, &memory_info, sizeof(memory_info))) |
| break; |
| size_t size = std::min((memory_info.RegionSize + kMask64k) & ~kMask64k, |
| static_cast<SIZE_T>(end - ptr)); |
| if (ptr && memory_info.State == MEM_FREE) |
| ::VirtualAllocEx(process, ptr, size, MEM_RESERVE, PAGE_NOACCESS); |
| ptr += size; |
| } |
| } |
| #endif |
| |
| return true; |
| } |
| |
| bool CanSetProcessMitigationsPostStartup(MitigationFlags flags) { |
| // All of these mitigations can be enabled after startup. |
| return !( |
| flags & |
| ~(MITIGATION_HEAP_TERMINATE | |
| MITIGATION_DEP | |
| MITIGATION_DEP_NO_ATL_THUNK | |
| MITIGATION_RELOCATE_IMAGE | |
| MITIGATION_RELOCATE_IMAGE_REQUIRED | |
| MITIGATION_BOTTOM_UP_ASLR | |
| MITIGATION_STRICT_HANDLE_CHECKS | |
| MITIGATION_EXTENSION_DLL_DISABLE | |
| MITIGATION_DLL_SEARCH_ORDER | |
| MITIGATION_HARDEN_TOKEN_IL_POLICY | |
| MITIGATION_WIN32K_DISABLE | |
| MITIGATION_NONSYSTEM_FONT_DISABLE | |
| MITIGATION_IMAGE_LOAD_NO_REMOTE | |
| MITIGATION_IMAGE_LOAD_NO_LOW_LABEL)); |
| } |
| |
| bool CanSetProcessMitigationsPreStartup(MitigationFlags flags) { |
| // These mitigations cannot be enabled prior to startup. |
| return !(flags & (MITIGATION_STRICT_HANDLE_CHECKS | |
| MITIGATION_DLL_SEARCH_ORDER)); |
| } |
| |
| } // namespace sandbox |
| |
