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Add mod security

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Due to compatibility concerns, this is temporarily disabled.
This commit is contained in:
ShadowNinja 2014-09-05 20:08:51 -04:00
parent f26421228b
commit 3a8c788880
22 changed files with 812 additions and 83 deletions
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3
build/android/jni/Android.mk
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@ -262,6 +262,7 @@ LOCAL_SRC_FILES += \
jni/src/script/common/c_converter.cpp \
jni/src/script/common/c_internal.cpp \
jni/src/script/common/c_types.cpp \
jni/src/script/cpp_api/s_async.cpp \
jni/src/script/cpp_api/s_base.cpp \
jni/src/script/cpp_api/s_entity.cpp \
jni/src/script/cpp_api/s_env.cpp \
@ -271,8 +272,8 @@ LOCAL_SRC_FILES += \
jni/src/script/cpp_api/s_node.cpp \
jni/src/script/cpp_api/s_nodemeta.cpp \
jni/src/script/cpp_api/s_player.cpp \
jni/src/script/cpp_api/s_security.cpp \
jni/src/script/cpp_api/s_server.cpp \
jni/src/script/cpp_api/s_async.cpp \
jni/src/script/lua_api/l_base.cpp \
jni/src/script/lua_api/l_craft.cpp \
jni/src/script/lua_api/l_env.cpp \

4
doc/lua_api.txt
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@ -1825,8 +1825,12 @@ Call these functions only at load time!
### Setting-related
* `minetest.setting_set(name, value)`
* Setting names can't contain whitespace or any of `="{}#`.
* Setting values can't contain the sequence `\n"""`.
* Setting names starting with "secure." can't be set.
* `minetest.setting_get(name)`: returns string or `nil`
* `minetest.setting_setbool(name, value)`
* See documentation on `setting_set` for restrictions.
* `minetest.setting_getbool(name)`: returns boolean or `nil`
* `minetest.setting_get_pos(name)`: returns position or nil
* `minetest.setting_save()`, returns `nil`, save all settings to config file

3
minetest.conf.example
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@ -569,3 +569,6 @@
#mgv7_np_cave1 = 0, 12, (100, 100, 100), 52534, 4, 0.5, 2.0
#mgv7_np_cave2 = 0, 12, (100, 100, 100), 10325, 4, 0.5, 2.0
# Prevent mods from doing insecure things like running shell commands.
#secure.enable_security = false

1
src/defaultsettings.cpp
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@ -272,6 +272,7 @@ void set_default_settings(Settings *settings)
settings->setDefault("emergequeue_limit_diskonly", "32");
settings->setDefault("emergequeue_limit_generate", "32");
settings->setDefault("num_emerge_threads", "1");
settings->setDefault("secure.enable_security", "false");
// physics stuff
settings->setDefault("movement_acceleration_default", "3");

13
src/filesys.cpp
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@ -662,6 +662,19 @@ std::string RemoveRelativePathComponents(std::string path)
return path.substr(0, pos);
}
std::string AbsolutePath(const std::string &path)
{
#ifdef _WIN32
char *abs_path = _fullpath(NULL, path.c_str(), MAX_PATH);
#else
char *abs_path = realpath(path.c_str(), NULL);
#endif
if (!abs_path) return "";
std::string abs_path_str(abs_path);
free(abs_path);
return abs_path_str;
}
const char *GetFilenameFromPath(const char *path)
{
const char *filename = strrchr(path, DIR_DELIM_CHAR);

10
src/filesys.h
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@ -103,13 +103,17 @@ std::string RemoveLastPathComponent(const std::string &path,
// this does not resolve symlinks and check for existence of directories.
std::string RemoveRelativePathComponents(std::string path);
// Return the filename from a path or the entire path if no directory delimiter
// is found.
// Returns the absolute path for the passed path, with "." and ".." path
// components and symlinks removed. Returns "" on error.
std::string AbsolutePath(const std::string &path);
// Returns the filename from a path or the entire path if no directory
// delimiter is found.
const char *GetFilenameFromPath(const char *path);
bool safeWriteToFile(const std::string &path, const std::string &content);
}//fs
} // namespace fs
#endif

4
src/script/common/c_internal.cpp
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@ -63,10 +63,8 @@ int script_exception_wrapper(lua_State *L, lua_CFunction f)
return f(L); // Call wrapped function and return result.
} catch (const char *s) { // Catch and convert exceptions.
lua_pushstring(L, s);
} catch (std::exception& e) {
} catch (std::exception &e) {
lua_pushstring(L, e.what());
} catch (...) {
lua_pushliteral(L, "caught (...)");
}
return lua_error(L); // Rethrow as a Lua error.
}

3
src/script/cpp_api/CMakeLists.txt
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@ -1,4 +1,5 @@
set(common_SCRIPT_CPP_API_SRCS
${CMAKE_CURRENT_SOURCE_DIR}/s_async.cpp
${CMAKE_CURRENT_SOURCE_DIR}/s_base.cpp
${CMAKE_CURRENT_SOURCE_DIR}/s_entity.cpp
${CMAKE_CURRENT_SOURCE_DIR}/s_env.cpp
@ -7,8 +8,8 @@ set(common_SCRIPT_CPP_API_SRCS
${CMAKE_CURRENT_SOURCE_DIR}/s_node.cpp
${CMAKE_CURRENT_SOURCE_DIR}/s_nodemeta.cpp
${CMAKE_CURRENT_SOURCE_DIR}/s_player.cpp
${CMAKE_CURRENT_SOURCE_DIR}/s_security.cpp
${CMAKE_CURRENT_SOURCE_DIR}/s_server.cpp
${CMAKE_CURRENT_SOURCE_DIR}/s_async.cpp
PARENT_SCOPE)
set(client_SCRIPT_CPP_API_SRCS

44
src/script/cpp_api/s_base.cpp
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@ -19,6 +19,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
#include "cpp_api/s_base.h"
#include "cpp_api/s_internal.h"
#include "cpp_api/s_security.h"
#include "lua_api/l_object.h"
#include "serverobject.h"
#include "debug.h"
@ -45,18 +46,18 @@ class ModNameStorer
private:
lua_State *L;
public:
ModNameStorer(lua_State *L_, const std::string &modname):
ModNameStorer(lua_State *L_, const std::string &mod_name):
L(L_)
{
// Store current modname in registry
lua_pushstring(L, modname.c_str());
lua_setfield(L, LUA_REGISTRYINDEX, "current_modname");
// Store current mod name in registry
lua_pushstring(L, mod_name.c_str());
lua_setfield(L, LUA_REGISTRYINDEX, SCRIPT_MOD_NAME_FIELD);
}
~ModNameStorer()
{
// Clear current modname in registry
// Clear current mod name from registry
lua_pushnil(L);
lua_setfield(L, LUA_REGISTRYINDEX, "current_modname");
lua_setfield(L, LUA_REGISTRYINDEX, SCRIPT_MOD_NAME_FIELD);
}
};
@ -112,32 +113,31 @@ ScriptApiBase::~ScriptApiBase()
lua_close(m_luastack);
}
bool ScriptApiBase::loadMod(const std::string &scriptpath,
const std::string &modname)
bool ScriptApiBase::loadMod(const std::string &script_path,
const std::string &mod_name)
{
ModNameStorer modnamestorer(getStack(), modname);
ModNameStorer mod_name_storer(getStack(), mod_name);
if (!string_allowed(modname, MODNAME_ALLOWED_CHARS)) {
errorstream<<"Error loading mod \""<<modname
<<"\": modname does not follow naming conventions: "
<<"Only chararacters [a-z0-9_] are allowed."<<std::endl;
return false;
}
return loadScript(scriptpath);
return loadScript(script_path);
}
bool ScriptApiBase::loadScript(const std::string &scriptpath)
bool ScriptApiBase::loadScript(const std::string &script_path)
{
verbosestream<<"Loading and running script from "<<scriptpath<<std::endl;
verbosestream << "Loading and running script from " << script_path << std::endl;
lua_State *L = getStack();
int ret = luaL_loadfile(L, scriptpath.c_str()) || lua_pcall(L, 0, 0, m_errorhandler);
if (ret) {
bool ok;
if (m_secure) {
ok = ScriptApiSecurity::safeLoadFile(L, script_path.c_str());
} else {
ok = !luaL_loadfile(L, script_path.c_str());
}
ok = ok && !lua_pcall(L, 0, 0, m_errorhandler);
if (!ok) {
errorstream << "========== ERROR FROM LUA ===========" << std::endl;
errorstream << "Failed to load and run script from " << std::endl;
errorstream << scriptpath << ":" << std::endl;
errorstream << script_path << ":" << std::endl;
errorstream << std::endl;
errorstream << lua_tostring(L, -1) << std::endl;
errorstream << std::endl;

15
src/script/cpp_api/s_base.h
View File

@ -35,6 +35,12 @@ extern "C" {
#define SCRIPTAPI_LOCK_DEBUG
#define SCRIPT_MOD_NAME_FIELD "current_mod_name"
// MUST be an invalid mod name so that mods can't
// use that name to bypass security!
#define BUILTIN_MOD_NAME "*builtin*"
class Server;
class Environment;
class GUIEngine;
@ -42,17 +48,18 @@ class ServerActiveObject;
class ScriptApiBase {
public:
ScriptApiBase();
virtual ~ScriptApiBase();
bool loadMod(const std::string &scriptpath, const std::string &modname);
bool loadScript(const std::string &scriptpath);
bool loadMod(const std::string &script_path, const std::string &mod_name);
bool loadScript(const std::string &script_path);
/* object */
void addObjectReference(ServerActiveObject *cobj);
void removeObjectReference(ServerActiveObject *cobj);
Server* getServer() { return m_server; }
protected:
friend class LuaABM;
friend class InvRef;
@ -69,7 +76,6 @@ protected:
void scriptError();
void stackDump(std::ostream &o);
Server* getServer() { return m_server; }
void setServer(Server* server) { m_server = server; }
Environment* getEnv() { return m_environment; }
@ -84,6 +90,7 @@ protected:
JMutex m_luastackmutex;
// Stack index of Lua error handler
int m_errorhandler;
bool m_secure;
#ifdef SCRIPTAPI_LOCK_DEBUG
bool m_locked;
#endif

603
src/script/cpp_api/s_security.cpp Normal file
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@ -0,0 +1,603 @@
/*
Minetest
Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "cpp_api/s_security.h"
#include "filesys.h"
#include "porting.h"
#include "server.h"
#include "settings.h"
#include <cerrno>
#include <string>
#include <iostream>
#define SECURE_API(lib, name) \
lua_pushcfunction(L, sl_##lib##_##name); \
lua_setfield(L, -2, #name);
static inline void copy_safe(lua_State *L, const char *list[], unsigned len, int from=-2, int to=-1)
{
if (from < 0) from = lua_gettop(L) + from + 1;
if (to < 0) to = lua_gettop(L) + to + 1;
for (unsigned i = 0; i < (len / sizeof(list[0])); i++) {
lua_getfield(L, from, list[i]);
lua_setfield(L, to, list[i]);
}
}
// Pushes the original version of a library function on the stack, from the old version
static inline void push_original(lua_State *L, const char *lib, const char *func)
{
lua_getfield(L, LUA_REGISTRYINDEX, "globals_backup");
lua_getfield(L, -1, lib);
lua_remove(L, -2); // Remove globals_backup
lua_getfield(L, -1, func);
lua_remove(L, -2); // Remove lib
}
void ScriptApiSecurity::initializeSecurity()
{
static const char *whitelist[] = {
"assert",
"core",
"collectgarbage",
"DIR_DELIM",
"error",
"getfenv",
"getmetatable",
"ipairs",
"next",
"pairs",
"pcall",
"print",
"rawequal",
"rawget",
"rawset",
"select",
"setfenv",
"setmetatable",
"tonumber",
"tostring",
"type",
"unpack",
"_VERSION",
"xpcall",
// Completely safe libraries
"coroutine",
"string",
"table",
"math",
};
static const char *io_whitelist[] = {
"close",
"flush",
"read",
"type",
"write",
};
static const char *os_whitelist[] = {
"clock",
"date",
"difftime",
"exit",
"getenv",
"setlocale",
"time",
"tmpname",
};
static const char *debug_whitelist[] = {
"gethook",
"traceback",
"getinfo",
"getmetatable",
"setupvalue",
"setmetatable",
"upvalueid",
"upvaluejoin",
"sethook",
"debug",
"getupvalue",
"setlocal",
};
static const char *package_whitelist[] = {
"config",
"cpath",
"path",
"searchpath",
};
static const char *jit_whitelist[] = {
"arch",
"flush",
"off",
"on",
"opt",
"os",
"status",
"version",
"version_num",
};
m_secure = true;
lua_State *L = getStack();
// Backup globals to the registry
lua_getglobal(L, "_G");
lua_setfield(L, LUA_REGISTRYINDEX, "globals_backup");
// Replace the global environment with an empty one
#if LUA_VERSION_NUM <= 501
int is_main = lua_pushthread(L); // Push the main thread
FATAL_ERROR_IF(!is_main, "Security: ScriptApi's Lua state "
"isn't the main Lua thread!");
#endif
lua_newtable(L); // Create new environment
lua_pushvalue(L, -1);
lua_setfield(L, -2, "_G"); // Set _G of new environment
#if LUA_VERSION_NUM >= 502 // Lua >= 5.2
// Set the global environment
lua_rawseti(L, LUA_REGISTRYINDEX, LUA_RIDX_GLOBALS);
#else // Lua <= 5.1
// Set the environment of the main thread
FATAL_ERROR_IF(!lua_setfenv(L, -2), "Security: Unable to set "
"environment of the main Lua thread!");
lua_pop(L, 1); // Pop thread
#endif
// Get old globals
lua_getfield(L, LUA_REGISTRYINDEX, "globals_backup");
int old_globals = lua_gettop(L);
// Copy safe base functions
lua_getglobal(L, "_G");
copy_safe(L, whitelist, sizeof(whitelist));
// And replace unsafe ones
SECURE_API(g, dofile);
SECURE_API(g, load);
SECURE_API(g, loadfile);
SECURE_API(g, loadstring);
SECURE_API(g, require);
lua_pop(L, 1);
// Copy safe IO functions
lua_getfield(L, old_globals, "io");
lua_newtable(L);
copy_safe(L, io_whitelist, sizeof(io_whitelist));
// And replace unsafe ones
SECURE_API(io, open);
SECURE_API(io, input);
SECURE_API(io, output);
SECURE_API(io, lines);
lua_setglobal(L, "io");
lua_pop(L, 1); // Pop old IO
// Copy safe OS functions
lua_getfield(L, old_globals, "os");
lua_newtable(L);
copy_safe(L, os_whitelist, sizeof(os_whitelist));
// And replace unsafe ones
SECURE_API(os, remove);
SECURE_API(os, rename);
lua_setglobal(L, "os");
lua_pop(L, 1); // Pop old OS
// Copy safe debug functions
lua_getfield(L, old_globals, "debug");
lua_newtable(L);
copy_safe(L, debug_whitelist, sizeof(debug_whitelist));
lua_setglobal(L, "debug");
lua_pop(L, 1); // Pop old debug
// Copy safe package fields
lua_getfield(L, old_globals, "package");
lua_newtable(L);
copy_safe(L, package_whitelist, sizeof(package_whitelist));
lua_setglobal(L, "package");
lua_pop(L, 1); // Pop old package
// Copy safe jit functions, if they exist
lua_getfield(L, -1, "jit");
if (!lua_isnil(L, -1)) {
lua_newtable(L);
copy_safe(L, jit_whitelist, sizeof(jit_whitelist));
lua_setglobal(L, "jit");
}
lua_pop(L, 1); // Pop old jit
lua_pop(L, 1); // Pop globals_backup
}
bool ScriptApiSecurity::isSecure(lua_State *L)
{
lua_getfield(L, LUA_REGISTRYINDEX, "globals_backup");
bool secure = !lua_isnil(L, -1);
lua_pop(L, 1);
return secure;
}
#define CHECK_FILE_ERR(ret, fp) \
if (ret) { \
if (fp) std::fclose(fp); \
lua_pushfstring(L, "%s: %s", path, strerror(errno)); \
return false; \
}
bool ScriptApiSecurity::safeLoadFile(lua_State *L, const char *path)
{
FILE *fp;
char *chunk_name;
if (path == NULL) {
fp = stdin;
chunk_name = const_cast<char *>("=stdin");
} else {
fp = fopen(path, "r");
if (!fp) {
lua_pushfstring(L, "%s: %s", path, strerror(errno));
return false;
}
chunk_name = new char[strlen(path) + 2];
chunk_name[0] = '@';
chunk_name[1] = '\0';
strcat(chunk_name, path);
}
size_t start = 0;
int c = std::getc(fp);
if (c == '#') {
// Skip the first line
while ((c = std::getc(fp)) != EOF && c != '\n');
if (c == '\n') c = std::getc(fp);
start = std::ftell(fp);
}
if (c == LUA_SIGNATURE[0]) {
lua_pushliteral(L, "Bytecode prohibited when mod security is enabled.");
return false;
}
// Read the file
int ret = std::fseek(fp, 0, SEEK_END);
CHECK_FILE_ERR(ret, fp);
if (ret) {
std::fclose(fp);
lua_pushfstring(L, "%s: %s", path, strerror(errno));
return false;
}
size_t size = std::ftell(fp) - start;
char *code = new char[size];
ret = std::fseek(fp, start, SEEK_SET);
CHECK_FILE_ERR(ret, fp);
if (ret) {
std::fclose(fp);
lua_pushfstring(L, "%s: %s", path, strerror(errno));
return false;
}
size_t num_read = std::fread(code, 1, size, fp);
if (path) {
std::fclose(fp);
}
if (num_read != size) {
lua_pushliteral(L, "Error reading file to load.");
return false;
}
if (luaL_loadbuffer(L, code, size, chunk_name)) {
return false;
}
if (path) {
delete [] chunk_name;
}
return true;
}
bool ScriptApiSecurity::checkPath(lua_State *L, const char *path)
{
std::string str; // Transient
std::string norel_path = fs::RemoveRelativePathComponents(path);
std::string abs_path = fs::AbsolutePath(norel_path);
if (!abs_path.empty()) {
// Don't allow accessing the settings file
str = fs::AbsolutePath(g_settings_path);
if (str == abs_path) return false;
}
// If we couldn't find the absolute path (path doesn't exist) then
// try removing the last components until it works (to allow
// non-existent files/folders for mkdir).
std::string cur_path = norel_path;
std::string removed;
while (abs_path.empty() && !cur_path.empty()) {
std::string tmp_rmed;
cur_path = fs::RemoveLastPathComponent(cur_path, &tmp_rmed);
removed = tmp_rmed + (removed.empty() ? "" : DIR_DELIM + removed);
abs_path = fs::AbsolutePath(cur_path);
}
if (abs_path.empty()) return false;
// Add the removed parts back so that you can't, eg, create a
// directory in worldmods if worldmods doesn't exist.
if (!removed.empty()) abs_path += DIR_DELIM + removed;
// Get server from registry
lua_getfield(L, LUA_REGISTRYINDEX, "scriptapi");
ScriptApiBase *script = (ScriptApiBase *) lua_touserdata(L, -1);
lua_pop(L, 1);
const Server *server = script->getServer();
if (!server) return false;
// Get mod name
lua_getfield(L, LUA_REGISTRYINDEX, SCRIPT_MOD_NAME_FIELD);
if (lua_isstring(L, -1)) {
std::string mod_name = lua_tostring(L, -1);
// Builtin can access anything
if (mod_name == BUILTIN_MOD_NAME) {
return true;
}
// Allow paths in mod path
const ModSpec *mod = server->getModSpec(mod_name);
if (mod) {
str = fs::AbsolutePath(mod->path);
if (!str.empty() && fs::PathStartsWith(abs_path, str)) {
return true;
}
}
}
lua_pop(L, 1); // Pop mod name
str = fs::AbsolutePath(server->getWorldPath());
if (str.empty()) return false;
// Don't allow access to world mods. We add to the absolute path
// of the world instead of getting the absolute paths directly
// because that won't work if they don't exist.
if (fs::PathStartsWith(abs_path, str + DIR_DELIM + "worldmods") ||
fs::PathStartsWith(abs_path, str + DIR_DELIM + "game")) {
return false;
}
// Allow all other paths in world path
if (fs::PathStartsWith(abs_path, str)) {
return true;
}
// Default to disallowing
return false;
}
int ScriptApiSecurity::sl_g_dofile(lua_State *L)
{
int nret = sl_g_loadfile(L);
if (nret != 1) {
return nret;
}
int top_precall = lua_gettop(L);
lua_call(L, 0, LUA_MULTRET);
// Return number of arguments returned by the function,
// adjusting for the function being poped.
return lua_gettop(L) - (top_precall - 1);
}
int ScriptApiSecurity::sl_g_load(lua_State *L)
{
size_t len;
const char *buf;
std::string code;
const char *chunk_name = "=(load)";
luaL_checktype(L, 1, LUA_TFUNCTION);
if (!lua_isnone(L, 2)) {
luaL_checktype(L, 2, LUA_TSTRING);
chunk_name = lua_tostring(L, 2);
}
while (true) {
lua_pushvalue(L, 1);
lua_call(L, 0, 1);
int t = lua_type(L, -1);
if (t == LUA_TNIL) {
break;
} else if (t != LUA_TSTRING) {
lua_pushnil(L);
lua_pushliteral(L, "Loader didn't return a string");
return 2;
}
buf = lua_tolstring(L, -1, &len);
code += std::string(buf, len);
lua_pop(L, 1); // Pop return value
}
if (code[0] == LUA_SIGNATURE[0]) {
lua_pushnil(L);
lua_pushliteral(L, "Bytecode prohibited when mod security is enabled.");
return 2;
}
if (luaL_loadbuffer(L, code.data(), code.size(), chunk_name)) {
lua_pushnil(L);
lua_insert(L, lua_gettop(L) - 1);
return 2;
}
return 1;
}
int ScriptApiSecurity::sl_g_loadfile(lua_State *L)
{
const char *path = NULL;
if (lua_isstring(L, 1)) {
path = lua_tostring(L, 1);
CHECK_SECURE_PATH(L, path);
}
if (!safeLoadFile(L, path)) {
lua_pushnil(L);
lua_insert(L, -2);
return 2;
}
return 1;
}
int ScriptApiSecurity::sl_g_loadstring(lua_State *L)
{
const char *chunk_name = "=(load)";
luaL_checktype(L, 1, LUA_TSTRING);
if (!lua_isnone(L, 2)) {
luaL_checktype(L, 2, LUA_TSTRING);
chunk_name = lua_tostring(L, 2);
}
size_t size;
const char *code = lua_tolstring(L, 1, &size);
if (size > 0 && code[0] == LUA_SIGNATURE[0]) {
lua_pushnil(L);
lua_pushliteral(L, "Bytecode prohibited when mod security is enabled.");
return 2;
}
if (luaL_loadbuffer(L, code, size, chunk_name)) {
lua_pushnil(L);
lua_insert(L, lua_gettop(L) - 1);
return 2;
}
return 1;
}
int ScriptApiSecurity::sl_g_require(lua_State *L)
{
lua_pushliteral(L, "require() is disabled when mod security is on.");
return lua_error(L);
}
int ScriptApiSecurity::sl_io_open(lua_State *L)
{
luaL_checktype(L, 1, LUA_TSTRING);
const char *path = lua_tostring(L, 1);
CHECK_SECURE_PATH(L, path);
push_original(L, "io", "open");
lua_pushvalue(L, 1);
lua_pushvalue(L, 2);
lua_call(L, 2, 2);
return 2;
}
int ScriptApiSecurity::sl_io_input(lua_State *L)
{
if (lua_isstring(L, 1)) {
const char *path = lua_tostring(L, 1);
CHECK_SECURE_PATH(L, path);
}
push_original(L, "io", "input");
lua_pushvalue(L, 1);
lua_call(L, 1, 1);
return 1;
}
int ScriptApiSecurity::sl_io_output(lua_State *L)
{
if (lua_isstring(L, 1)) {
const char *path = lua_tostring(L, 1);
CHECK_SECURE_PATH(L, path);
}
push_original(L, "io", "output");
lua_pushvalue(L, 1);
lua_call(L, 1, 1);
return 1;
}
int ScriptApiSecurity::sl_io_lines(lua_State *L)
{
if (lua_isstring(L, 1)) {
const char *path = lua_tostring(L, 1);
CHECK_SECURE_PATH(L, path);
}
push_original(L, "io", "lines");
lua_pushvalue(L, 1);
int top_precall = lua_gettop(L);
lua_call(L, 1, LUA_MULTRET);
// Return number of arguments returned by the function,
// adjusting for the function being poped.
return lua_gettop(L) - (top_precall - 1);
}
int ScriptApiSecurity::sl_os_rename(lua_State *L)
{
luaL_checktype(L, 1, LUA_TSTRING);
const char *path1 = lua_tostring(L, 1);
CHECK_SECURE_PATH(L, path1);
luaL_checktype(L, 2, LUA_TSTRING);
const char *path2 = lua_tostring(L, 2);
CHECK_SECURE_PATH(L, path2);
push_original(L, "os", "rename");
lua_pushvalue(L, 1);
lua_pushvalue(L, 2);
lua_call(L, 2, 2);
return 2;
}
int ScriptApiSecurity::sl_os_remove(lua_State *L)
{
luaL_checktype(L, 1, LUA_TSTRING);
const char *path = lua_tostring(L, 1);
CHECK_SECURE_PATH(L, path);
push_original(L, "os", "remove");
lua_pushvalue(L, 1);
lua_call(L, 1, 2);
return 2;
}

70
src/script/cpp_api/s_security.h Normal file
View File

@ -0,0 +1,70 @@
/*
Minetest
Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifndef S_SECURITY_H
#define S_SECURITY_H
#include "cpp_api/s_base.h"
#define CHECK_SECURE_PATH(L, path) \
if (!ScriptApiSecurity::checkPath(L, path)) { \
lua_pushstring(L, (std::string("Attempt to access external file ") + \
path + " with mod security on.").c_str()); \
lua_error(L); \
}
#define CHECK_SECURE_PATH_OPTIONAL(L, path) \
if (ScriptApiSecurity::isSecure(L)) { \
CHECK_SECURE_PATH(L, path); \
}
class ScriptApiSecurity : virtual public ScriptApiBase
{
public:
// Sets up security on the ScriptApi's Lua state
void initializeSecurity();
// Checks if the Lua state has been secured
static bool isSecure(lua_State *L);
// Loads a file as Lua code safely (doesn't allow bytecode).
static bool safeLoadFile(lua_State *L, const char *path);
// Checks if mods are allowed to read and write to the path
static bool checkPath(lua_State *L, const char *path);
private:
// Syntax: "sl_" <Library name or 'g' (global)> '_' <Function name>
// (sl stands for Secure Lua)
static int sl_g_dofile(lua_State *L);
static int sl_g_load(lua_State *L);
static int sl_g_loadfile(lua_State *L);
static int sl_g_loadstring(lua_State *L);
static int sl_g_require(lua_State *L);
static int sl_io_open(lua_State *L);
static int sl_io_input(lua_State *L);
static int sl_io_output(lua_State *L);
static int sl_io_lines(lua_State *L);
static int sl_os_rename(lua_State *L);
static int sl_os_remove(lua_State *L);
};
#endif

7
src/script/lua_api/l_mapgen.cpp
View File

@ -22,6 +22,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
#include "lua_api/l_vmanip.h"
#include "common/c_converter.h"
#include "common/c_content.h"
#include "cpp_api/s_security.h"
#include "util/serialize.h"
#include "server.h"
#include "environment.h"
@ -1031,6 +1032,10 @@ int ModApiMapgen::l_generate_decorations(lua_State *L)
int ModApiMapgen::l_create_schematic(lua_State *L)
{
INodeDefManager *ndef = getServer(L)->getNodeDefManager();
const char *filename = luaL_checkstring(L, 4);
CHECK_SECURE_PATH_OPTIONAL(L, filename);
Map *map = &(getEnv(L)->getMap());
Schematic schem;
@ -1069,8 +1074,6 @@ int ModApiMapgen::l_create_schematic(lua_State *L)
}
}
const char *filename = luaL_checkstring(L, 4);
if (!schem.getSchematicFromMap(map, p1, p2)) {
errorstream << "create_schematic: failed to get schematic "
"from map" << std::endl;

3
src/script/lua_api/l_server.cpp
View File

@ -21,6 +21,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
#include "lua_api/l_internal.h"
#include "common/c_converter.h"
#include "common/c_content.h"
#include "cpp_api/s_base.h"
#include "server.h"
#include "environment.h"
#include "player.h"
@ -342,7 +343,7 @@ int ModApiServer::l_show_formspec(lua_State *L)
int ModApiServer::l_get_current_modname(lua_State *L)
{
NO_MAP_LOCK_REQUIRED;
lua_getfield(L, LUA_REGISTRYINDEX, "current_modname");
lua_getfield(L, LUA_REGISTRYINDEX, SCRIPT_MOD_NAME_FIELD);
return 1;
}

2
src/script/lua_api/l_settings.cpp
View File

@ -19,6 +19,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
#include "lua_api/l_settings.h"
#include "lua_api/l_internal.h"
#include "cpp_api/s_security.h"
#include "settings.h"
#include "log.h"
@ -188,6 +189,7 @@ int LuaSettings::create_object(lua_State* L)
{
NO_MAP_LOCK_REQUIRED;
const char* filename = luaL_checkstring(L, 1);
CHECK_SECURE_PATH_OPTIONAL(L, filename);
LuaSettings* o = new LuaSettings(filename);
*(void **)(lua_newuserdata(L, sizeof(void *))) = o;
luaL_getmetatable(L, className);

14
src/script/lua_api/l_util.cpp
View File

@ -92,12 +92,19 @@ int ModApiUtil::l_log(lua_State *L)
return 0;
}
#define CHECK_SECURE_SETTING(L, name) \
if (name.compare(0, 7, "secure.") == 0) {\
lua_pushliteral(L, "Attempt to set secure setting.");\
lua_error(L);\
}
// setting_set(name, value)
int ModApiUtil::l_setting_set(lua_State *L)
{
NO_MAP_LOCK_REQUIRED;
const char *name = luaL_checkstring(L, 1);
const char *value = luaL_checkstring(L, 2);
std::string name = luaL_checkstring(L, 1);
std::string value = luaL_checkstring(L, 2);
CHECK_SECURE_SETTING(L, name);
g_settings->set(name, value);
return 0;
}
@ -120,8 +127,9 @@ int ModApiUtil::l_setting_get(lua_State *L)
int ModApiUtil::l_setting_setbool(lua_State *L)
{
NO_MAP_LOCK_REQUIRED;
const char *name = luaL_checkstring(L, 1);
std::string name = luaL_checkstring(L, 1);
bool value = lua_toboolean(L, 2);
CHECK_SECURE_SETTING(L, name);
g_settings->setBool(name, value);
return 0;
}

7
src/script/scripting_game.cpp
View File

@ -20,6 +20,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
#include "scripting_game.h"
#include "server.h"
#include "log.h"
#include "settings.h"
#include "cpp_api/s_internal.h"
#include "lua_api/l_base.h"
#include "lua_api/l_craft.h"
@ -49,10 +50,12 @@ GameScripting::GameScripting(Server* server)
// setEnv(env) is called by ScriptApiEnv::initializeEnvironment()
// once the environment has been created
//TODO add security
SCRIPTAPI_PRECHECKHEADER
if (g_settings->getBool("secure.enable_security")) {
initializeSecurity();
}
lua_getglobal(L, "core");
int top = lua_gettop(L);

8
src/script/scripting_game.h
View File

@ -27,19 +27,21 @@ with this program; if not, write to the Free Software Foundation, Inc.,
#include "cpp_api/s_node.h"
#include "cpp_api/s_player.h"
#include "cpp_api/s_server.h"
#include "cpp_api/s_security.h"
/*****************************************************************************/
/* Scripting <-> Game Interface */
/*****************************************************************************/
class GameScripting
: virtual public ScriptApiBase,
class GameScripting :
virtual public ScriptApiBase,
public ScriptApiDetached,
public ScriptApiEntity,
public ScriptApiEnv,
public ScriptApiNode,
public ScriptApiPlayer,
public ScriptApiServer
public ScriptApiServer,
public ScriptApiSecurity
{
public:
GameScripting(Server* server);

2
src/script/scripting_mainmenu.cpp
View File

@ -38,8 +38,6 @@ MainMenuScripting::MainMenuScripting(GUIEngine* guiengine)
{
setGuiEngine(guiengine);
//TODO add security
SCRIPTAPI_PRECHECKHEADER
lua_getglobal(L, "core");

50
src/server.cpp
View File

@ -295,31 +295,37 @@ Server::Server(
m_script = new GameScripting(this);
std::string scriptpath = getBuiltinLuaPath() + DIR_DELIM "init.lua";
std::string script_path = getBuiltinLuaPath() + DIR_DELIM "init.lua";
if (!m_script->loadScript(scriptpath))
throw ModError("Failed to load and run " + scriptpath);
// Print 'em
infostream<<"Server: Loading mods: ";
for(std::vector<ModSpec>::iterator i = m_mods.begin();
i != m_mods.end(); i++){
const ModSpec &mod = *i;
infostream<<mod.name<<" ";
if (!m_script->loadMod(script_path, BUILTIN_MOD_NAME)) {
throw ModError("Failed to load and run " + script_path);
}
infostream<<std::endl;
// Load and run "mod" scripts
// Print mods
infostream << "Server: Loading mods: ";
for(std::vector<ModSpec>::iterator i = m_mods.begin();
i != m_mods.end(); i++){
const ModSpec &mod = *i;
std::string scriptpath = mod.path + DIR_DELIM + "init.lua";
infostream<<" ["<<padStringRight(mod.name, 12)<<"] [\""
<<scriptpath<<"\"]"<<std::endl;
bool success = m_script->loadMod(scriptpath, mod.name);
if(!success){
errorstream<<"Server: Failed to load and run "
<<scriptpath<<std::endl;
throw ModError("Failed to load and run "+scriptpath);
infostream << mod.name << " ";
}
infostream << std::endl;
// Load and run "mod" scripts
for (std::vector<ModSpec>::iterator i = m_mods.begin();
i != m_mods.end(); i++) {
const ModSpec &mod = *i;
if (!string_allowed(mod.name, MODNAME_ALLOWED_CHARS)) {
errorstream << "Error loading mod \"" << mod.name
<< "\": mod_name does not follow naming conventions: "
<< "Only chararacters [a-z0-9_] are allowed." << std::endl;
throw ModError("Mod \"" + mod.name + "\" does not follow naming conventions.");
}
std::string script_path = mod.path + DIR_DELIM "init.lua";
infostream << " [" << padStringRight(mod.name, 12) << "] [\""
<< script_path << "\"]" << std::endl;
if (!m_script->loadMod(script_path, mod.name)) {
errorstream << "Server: Failed to load and run "
<< script_path << std::endl;
throw ModError("Failed to load and run " + script_path);
}
}
@ -3206,9 +3212,9 @@ IWritableCraftDefManager* Server::getWritableCraftDefManager()
return m_craftdef;
}
const ModSpec* Server::getModSpec(const std::string &modname)
const ModSpec* Server::getModSpec(const std::string &modname) const
{
for(std::vector<ModSpec>::iterator i = m_mods.begin();
for(std::vector<ModSpec>::const_iterator i = m_mods.begin();
i != m_mods.end(); i++){
const ModSpec &mod = *i;
if(mod.name == modname)

4
src/server.h
View File

@ -322,10 +322,10 @@ public:
IWritableNodeDefManager* getWritableNodeDefManager();
IWritableCraftDefManager* getWritableCraftDefManager();
const ModSpec* getModSpec(const std::string &modname);
const ModSpec* getModSpec(const std::string &modname) const;
void getModNames(std::vector<std::string> &modlist);
std::string getBuiltinLuaPath();
inline std::string getWorldPath()
inline std::string getWorldPath() const
{ return m_path_world; }
inline bool isSingleplayer()

15
src/settings.cpp
View File

@ -68,10 +68,11 @@ Settings & Settings::operator = (const Settings &other)
bool Settings::checkNameValid(const std::string &name)
{
size_t pos = name.find_first_of("\t\n\v\f\r\b =\"{}#");
if (pos != std::string::npos) {
errorstream << "Invalid character '" << name[pos]
<< "' found in setting name" << std::endl;
bool valid = name.find_first_of("=\"{}#") == std::string::npos;
if (valid) valid = trim(name) == name;
if (!valid) {
errorstream << "Invalid setting name \"" << name << "\""
<< std::endl;
return false;
}
return true;
@ -83,7 +84,7 @@ bool Settings::checkValueValid(const std::string &value)
if (value.substr(0, 3) == "\"\"\"" ||
value.find("\n\"\"\"") != std::string::npos) {
errorstream << "Invalid character sequence '\"\"\"' found in"
" setting value" << std::endl;
" setting value!" << std::endl;
return false;
}
return true;
@ -92,9 +93,9 @@ bool Settings::checkValueValid(const std::string &value)
std::string Settings::sanitizeName(const std::string &name)
{
std::string n(name);
std::string n = trim(name);
for (const char *s = "\t\n\v\f\r\b =\"{}#"; *s; s++)
for (const char *s = "=\"{}#"; *s; s++)
n.erase(std::remove(n.begin(), n.end(), *s), n.end());
return n;