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// Copyright (c) 2006-2008 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/registry_policy.h"
#include <stdint.h>
#include <string>
#include "base/logging.h"
#include "sandbox/win/src/ipc_tags.h"
#include "sandbox/win/src/policy_engine_opcodes.h"
#include "sandbox/win/src/policy_params.h"
#include "sandbox/win/src/sandbox_types.h"
#include "sandbox/win/src/sandbox_utils.h"
#include "sandbox/win/src/win_utils.h"
namespace {
static const uint32_t kAllowedRegFlags =
KEY_QUERY_VALUE | KEY_ENUMERATE_SUB_KEYS | KEY_NOTIFY | KEY_READ |
GENERIC_READ | GENERIC_EXECUTE | READ_CONTROL | KEY_WOW64_64KEY |
KEY_WOW64_32KEY;
// Opens the key referenced by |obj_attributes| with |access| and
// checks what permission was given. Remove the WRITE flags and update
// |access| with the new value.
NTSTATUS TranslateMaximumAllowed(OBJECT_ATTRIBUTES* obj_attributes,
DWORD* access) {
NtOpenKeyFunction NtOpenKey = nullptr;
ResolveNTFunctionPtr("NtOpenKey", &NtOpenKey);
NtCloseFunction NtClose = nullptr;
ResolveNTFunctionPtr("NtClose", &NtClose);
NtQueryObjectFunction NtQueryObject = nullptr;
ResolveNTFunctionPtr("NtQueryObject", &NtQueryObject);
// Open the key.
HANDLE handle;
NTSTATUS status = NtOpenKey(&handle, *access, obj_attributes);
if (!NT_SUCCESS(status))
return status;
OBJECT_BASIC_INFORMATION info = {0};
status = NtQueryObject(handle, ObjectBasicInformation, &info, sizeof(info),
nullptr);
CHECK(NT_SUCCESS(NtClose(handle)));
if (!NT_SUCCESS(status))
return status;
*access = info.GrantedAccess & kAllowedRegFlags;
return STATUS_SUCCESS;
}
NTSTATUS NtCreateKeyInTarget(HANDLE* target_key_handle,
ACCESS_MASK desired_access,
OBJECT_ATTRIBUTES* obj_attributes,
ULONG title_index,
UNICODE_STRING* class_name,
ULONG create_options,
ULONG* disposition,
HANDLE target_process) {
*target_key_handle = nullptr;
NtCreateKeyFunction NtCreateKey = nullptr;
ResolveNTFunctionPtr("NtCreateKey", &NtCreateKey);
if (MAXIMUM_ALLOWED & desired_access) {
NTSTATUS status = TranslateMaximumAllowed(obj_attributes, &desired_access);
if (!NT_SUCCESS(status))
return STATUS_ACCESS_DENIED;
}
HANDLE local_handle = INVALID_HANDLE_VALUE;
NTSTATUS status =
NtCreateKey(&local_handle, desired_access, obj_attributes, title_index,
class_name, create_options, disposition);
if (!NT_SUCCESS(status))
return status;
if (!::DuplicateHandle(::GetCurrentProcess(), local_handle, target_process,
target_key_handle, 0, false,
DUPLICATE_CLOSE_SOURCE | DUPLICATE_SAME_ACCESS)) {
return STATUS_ACCESS_DENIED;
}
return STATUS_SUCCESS;
}
NTSTATUS NtOpenKeyInTarget(HANDLE* target_key_handle,
ACCESS_MASK desired_access,
OBJECT_ATTRIBUTES* obj_attributes,
HANDLE target_process) {
*target_key_handle = nullptr;
NtOpenKeyFunction NtOpenKey = nullptr;
ResolveNTFunctionPtr("NtOpenKey", &NtOpenKey);
if (MAXIMUM_ALLOWED & desired_access) {
NTSTATUS status = TranslateMaximumAllowed(obj_attributes, &desired_access);
if (!NT_SUCCESS(status))
return STATUS_ACCESS_DENIED;
}
HANDLE local_handle = INVALID_HANDLE_VALUE;
NTSTATUS status = NtOpenKey(&local_handle, desired_access, obj_attributes);
if (!NT_SUCCESS(status))
return status;
if (!::DuplicateHandle(::GetCurrentProcess(), local_handle, target_process,
target_key_handle, 0, false,
DUPLICATE_CLOSE_SOURCE | DUPLICATE_SAME_ACCESS)) {
return STATUS_ACCESS_DENIED;
}
return STATUS_SUCCESS;
}
} // namespace
namespace sandbox {
bool RegistryPolicy::GenerateRules(const wchar_t* name,
TargetPolicy::Semantics semantics,
LowLevelPolicy* policy) {
std::wstring resolved_name(name);
if (resolved_name.empty()) {
return false;
}
if (!ResolveRegistryName(resolved_name, &resolved_name))
return false;
name = resolved_name.c_str();
EvalResult result = ASK_BROKER;
PolicyRule open(result);
PolicyRule create(result);
switch (semantics) {
case TargetPolicy::REG_ALLOW_READONLY: {
// We consider all flags that are not known to be readonly as potentially
// used for write. Here we also support MAXIMUM_ALLOWED, but we are going
// to expand it to read-only before the call.
uint32_t restricted_flags = ~(kAllowedRegFlags | MAXIMUM_ALLOWED);
open.AddNumberMatch(IF_NOT, OpenKey::ACCESS, restricted_flags, AND);
create.AddNumberMatch(IF_NOT, OpenKey::ACCESS, restricted_flags, AND);
break;
}
case TargetPolicy::REG_ALLOW_ANY: {
break;
}
default: {
NOTREACHED();
return false;
}
}
if (!create.AddStringMatch(IF, OpenKey::NAME, name, CASE_INSENSITIVE) ||
!policy->AddRule(IpcTag::NTCREATEKEY, &create)) {
return false;
}
if (!open.AddStringMatch(IF, OpenKey::NAME, name, CASE_INSENSITIVE) ||
!policy->AddRule(IpcTag::NTOPENKEY, &open)) {
return false;
}
return true;
}
bool RegistryPolicy::CreateKeyAction(EvalResult eval_result,
const ClientInfo& client_info,
const std::wstring& key,
uint32_t attributes,
HANDLE root_directory,
uint32_t desired_access,
uint32_t title_index,
uint32_t create_options,
HANDLE* handle,
NTSTATUS* nt_status,
ULONG* disposition) {
// The only action supported is ASK_BROKER which means create the requested
// file as specified.
if (ASK_BROKER != eval_result) {
*nt_status = STATUS_ACCESS_DENIED;
return false;
}
// We don't support creating link keys, volatile keys or backup/restore.
if (create_options) {
*nt_status = STATUS_ACCESS_DENIED;
return false;
}
UNICODE_STRING uni_name = {0};
OBJECT_ATTRIBUTES obj_attributes = {0};
InitObjectAttribs(key, attributes, root_directory, &obj_attributes, &uni_name,
nullptr);
*nt_status = NtCreateKeyInTarget(handle, desired_access, &obj_attributes,
title_index, nullptr, create_options,
disposition, client_info.process);
return true;
}
bool RegistryPolicy::OpenKeyAction(EvalResult eval_result,
const ClientInfo& client_info,
const std::wstring& key,
uint32_t attributes,
HANDLE root_directory,
uint32_t desired_access,
HANDLE* handle,
NTSTATUS* nt_status) {
// The only action supported is ASK_BROKER which means open the requested
// file as specified.
if (ASK_BROKER != eval_result) {
*nt_status = STATUS_ACCESS_DENIED;
return false;
}
UNICODE_STRING uni_name = {0};
OBJECT_ATTRIBUTES obj_attributes = {0};
InitObjectAttribs(key, attributes, root_directory, &obj_attributes, &uni_name,
nullptr);
*nt_status = NtOpenKeyInTarget(handle, desired_access, &obj_attributes,
client_info.process);
return true;
}
} // namespace sandbox
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