#include "filesys.h"
#include "porting.h"
#include "server.h"
+#include "client/client.h"
#include "settings.h"
#include <cerrno>
"math",
};
static const char *io_whitelist[] = {
+ "open",
"close",
"flush",
"read",
"clock",
"date",
"difftime",
- "exit",
"getenv",
"setlocale",
"time",
"setupvalue",
"setmetatable",
"upvalueid",
- "upvaluejoin",
"sethook",
"debug",
"setlocal",
"path",
"searchpath",
};
+#if USE_LUAJIT
static const char *jit_whitelist[] = {
"arch",
"flush",
"version",
"version_num",
};
-
+#endif
m_secure = true;
lua_State *L = getStack();
lua_rawseti(L, LUA_REGISTRYINDEX, CUSTOM_RIDX_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
+ int thread = getThread(L);
+ createEmptyEnv(L);
+ setLuaEnv(L, thread);
// Get old globals
lua_rawgeti(L, LUA_REGISTRYINDEX, CUSTOM_RIDX_GLOBALS_BACKUP);
copy_safe(L, io_whitelist, sizeof(io_whitelist));
// And replace unsafe ones
- SECURE_API(io, open);
+ //SECURE_API(io, open);
SECURE_API(io, input);
SECURE_API(io, output);
SECURE_API(io, lines);
lua_setglobal(L, "package");
lua_pop(L, 1); // Pop old package
-
+#if USE_LUAJIT
// Copy safe jit functions, if they exist
lua_getfield(L, -1, "jit");
if (!lua_isnil(L, -1)) {
lua_setglobal(L, "jit");
}
lua_pop(L, 1); // Pop old jit
+#endif
lua_pop(L, 1); // Pop globals_backup
}
+void ScriptApiSecurity::initializeSecurityClient()
+{
+ static const char *whitelist[] = {
+ "assert",
+ "core",
+ "collectgarbage",
+ "DIR_DELIM",
+ "error",
+ "getfenv",
+ "ipairs",
+ "next",
+ "pairs",
+ "pcall",
+ "print",
+ "rawequal",
+ "rawget",
+ "rawset",
+ "select",
+ "setfenv",
+ // getmetatable can be used to escape the sandbox
+ "setmetatable",
+ "tonumber",
+ "tostring",
+ "type",
+ "unpack",
+ "_VERSION",
+ "xpcall",
+ // Completely safe libraries
+ "coroutine",
+ "string",
+ "table",
+ "math",
+ };
+ static const char *os_whitelist[] = {
+ "clock",
+ "date",
+ "difftime",
+ "time"
+ };
+ static const char *debug_whitelist[] = {
+ "getinfo",
+ "traceback"
+ };
+#if USE_LUAJIT
+ static const char *jit_whitelist[] = {
+ "arch",
+ "flush",
+ "off",
+ "on",
+ "opt",
+ "os",
+ "status",
+ "version",
+ "version_num",
+ };
+#endif
+
+ m_secure = true;
+
+ lua_State *L = getStack();
+ int thread = getThread(L);
+
+ // Backup globals to the registry
+ lua_getglobal(L, "_G");
+ lua_rawseti(L, LUA_REGISTRYINDEX, CUSTOM_RIDX_GLOBALS_BACKUP);
+
+ // create an empty environment
+ createEmptyEnv(L);
+
+ // Copy safe base functions
+ lua_getglobal(L, "_G");
+ lua_getfield(L, -2, "_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, 2);
+
+ // Copy safe OS functions
+ lua_getglobal(L, "os");
+ lua_newtable(L);
+ copy_safe(L, os_whitelist, sizeof(os_whitelist));
+ lua_setfield(L, -3, "os");
+ lua_pop(L, 1); // Pop old OS
+
+
+ // Copy safe debug functions
+ lua_getglobal(L, "debug");
+ lua_newtable(L);
+ copy_safe(L, debug_whitelist, sizeof(debug_whitelist));
+ lua_setfield(L, -3, "debug");
+ lua_pop(L, 1); // Pop old debug
+
+
+#if USE_LUAJIT
+ // Copy safe jit functions, if they exist
+ lua_getglobal(L, "jit");
+ lua_newtable(L);
+ copy_safe(L, jit_whitelist, sizeof(jit_whitelist));
+ lua_setfield(L, -3, "jit");
+ lua_pop(L, 1); // Pop old jit
+#endif
+
+ // Set the environment to the one we created earlier
+ setLuaEnv(L, thread);
+}
+
+int ScriptApiSecurity::getThread(lua_State *L)
+{
+#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!");
+ return lua_gettop(L);
+#endif
+ return 0;
+}
+
+void ScriptApiSecurity::createEmptyEnv(lua_State *L)
+{
+ lua_newtable(L); // Create new environment
+ lua_pushvalue(L, -1);
+ lua_setfield(L, -2, "_G"); // Create the _G loop
+}
+
+void ScriptApiSecurity::setLuaEnv(lua_State *L, int thread)
+{
+#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, thread), "Security: Unable to set "
+ "environment of the main Lua thread!");
+ lua_pop(L, 1); // Pop thread
+#endif
+}
bool ScriptApiSecurity::isSecure(lua_State *L)
{
return secure;
}
-
-#define CHECK_FILE_ERR(ret, fp) \
- if (ret) { \
- lua_pushfstring(L, "%s: %s", path, strerror(errno)); \
- if (fp) std::fclose(fp); \
- return false; \
+bool ScriptApiSecurity::safeLoadString(lua_State *L, const std::string &code, const char *chunk_name)
+{
+ if (code.size() > 0 && code[0] == LUA_SIGNATURE[0]) {
+ lua_pushliteral(L, "Bytecode prohibited when mod security is enabled.");
+ return false;
}
+ if (luaL_loadbuffer(L, code.data(), code.size(), chunk_name))
+ return false;
+ return true;
+}
-
-bool ScriptApiSecurity::safeLoadFile(lua_State *L, const char *path)
+bool ScriptApiSecurity::safeLoadFile(lua_State *L, const char *path, const char *display_name)
{
FILE *fp;
char *chunk_name;
- if (path == NULL) {
+ if (!display_name)
+ display_name = path;
+ if (!path) {
fp = stdin;
chunk_name = const_cast<char *>("=stdin");
} else {
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 len = strlen(display_name) + 2;
+ chunk_name = new char[len];
+ snprintf(chunk_name, len, "@%s", display_name);
}
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);
+ while ((c = std::getc(fp)) != EOF && c != '\n') {}
+ if (c == '\n')
+ std::getc(fp);
start = std::ftell(fp);
}
- if (c == LUA_SIGNATURE[0]) {
- lua_pushliteral(L, "Bytecode prohibited when mod security is enabled.");
- std::fclose(fp);
+ // Read the file
+ int ret = std::fseek(fp, 0, SEEK_END);
+ if (ret) {
+ lua_pushfstring(L, "%s: %s", path, strerror(errno));
if (path) {
+ std::fclose(fp);
delete [] chunk_name;
}
return false;
}
- // Read the file
- int ret = std::fseek(fp, 0, SEEK_END);
- CHECK_FILE_ERR(ret, fp);
-
size_t size = std::ftell(fp) - start;
- char *code = new char[size];
+ std::string code(size, '\0');
ret = std::fseek(fp, start, SEEK_SET);
if (ret) {
lua_pushfstring(L, "%s: %s", path, strerror(errno));
- std::fclose(fp);
- delete [] code;
if (path) {
+ std::fclose(fp);
delete [] chunk_name;
}
return false;
}
- size_t num_read = std::fread(code, 1, size, fp);
- if (path) {
+ size_t num_read = std::fread(&code[0], 1, size, fp);
+ if (path)
std::fclose(fp);
- }
if (num_read != size) {
lua_pushliteral(L, "Error reading file to load.");
- delete [] code;
- if (path) {
+ if (path)
delete [] chunk_name;
- }
return false;
}
- if (luaL_loadbuffer(L, code, size, chunk_name)) {
- return false;
- }
-
- if (path) {
+ bool result = safeLoadString(L, code, chunk_name);
+ if (path)
delete [] chunk_name;
- }
- return true;
+ return result;
}
-bool ScriptApiSecurity::checkPath(lua_State *L, const char *path)
+bool ScriptApiSecurity::checkPath(lua_State *L, const char *path,
+ bool write_required, bool *write_allowed)
{
+ if (write_allowed)
+ *write_allowed = false;
+
std::string str; // Transient
- std::string norel_path = fs::RemoveRelativePathComponents(path);
- std::string abs_path = fs::AbsolutePath(norel_path);
+ std::string abs_path = fs::AbsolutePath(path);
if (!abs_path.empty()) {
// Don't allow accessing the settings file
// 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 cur_path = 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);
+ std::string component;
+ cur_path = fs::RemoveLastPathComponent(cur_path, &component);
+ if (component == "..") {
+ // Parent components can't be allowed or we could allow something like
+ // /home/user/minetest/worlds/foo/noexist/../../../../../../etc/passwd.
+ // If we have previous non-relative elements in the path we might be
+ // able to remove them so that things like worlds/foo/noexist/../auth.txt
+ // could be allowed, but those paths will be interpreted as nonexistent
+ // by the operating system anyways.
+ return false;
+ }
+ removed.append(component).append(removed.empty() ? "" : DIR_DELIM + removed);
abs_path = fs::AbsolutePath(cur_path);
}
- if (abs_path.empty()) return false;
+ 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;
+ if (!removed.empty())
+ abs_path += DIR_DELIM + removed;
// Get server from registry
lua_rawgeti(L, LUA_REGISTRYINDEX, CUSTOM_RIDX_SCRIPTAPI);
- ScriptApiBase *script = (ScriptApiBase *) lua_touserdata(L, -1);
+ ScriptApiBase *script;
+#if INDIRECT_SCRIPTAPI_RIDX
+ script = (ScriptApiBase *) *(void**)(lua_touserdata(L, -1));
+#else
+ script = (ScriptApiBase *) lua_touserdata(L, -1);
+#endif
lua_pop(L, 1);
- const Server *server = script->getServer();
-
- if (!server) return false;
+ const IGameDef *gamedef = script->getGameDef();
+ if (!gamedef)
+ return false;
// Get mod name
lua_rawgeti(L, LUA_REGISTRYINDEX, CUSTOM_RIDX_CURRENT_MOD_NAME);
if (lua_isstring(L, -1)) {
- std::string mod_name = lua_tostring(L, -1);
+ std::string mod_name = readParam<std::string>(L, -1);
// Builtin can access anything
if (mod_name == BUILTIN_MOD_NAME) {
+ if (write_allowed) *write_allowed = true;
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;
+ // Don't bother if write access isn't important, since it will be handled later
+ if (write_required || write_allowed != NULL) {
+ const ModSpec *mod = gamedef->getModSpec(mod_name);
+ if (mod) {
+ str = fs::AbsolutePath(mod->path);
+ if (!str.empty() && fs::PathStartsWith(abs_path, str)) {
+ if (write_allowed) *write_allowed = true;
+ 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 read-only access to all mod directories
+ if (!write_required) {
+ const std::vector<ModSpec> &mods = gamedef->getMods();
+ for (const ModSpec &mod : mods) {
+ str = fs::AbsolutePath(mod.path);
+ if (!str.empty() && fs::PathStartsWith(abs_path, str)) {
+ return true;
+ }
+ }
}
- // Allow all other paths in world path
- if (fs::PathStartsWith(abs_path, str)) {
- return true;
+
+ str = fs::AbsolutePath(gamedef->getWorldPath());
+ if (!str.empty()) {
+ // Don't allow access to other paths in the world mod/game path.
+ // These have to be blocked so you can't override a trusted mod
+ // by creating a mod with the same name in a world mod directory.
+ // 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)) {
+ if (write_allowed) *write_allowed = true;
+ return true;
+ }
}
// Default to disallowing
int t = lua_type(L, -1);
if (t == LUA_TNIL) {
break;
- } else if (t != LUA_TSTRING) {
+ }
+
+ if (t != LUA_TSTRING) {
lua_pushnil(L);
lua_pushliteral(L, "Loader didn't return a string");
return 2;
code += std::string(buf, len);
lua_pop(L, 1); // Pop return value
}
- if (code[0] == LUA_SIGNATURE[0]) {
+ if (!safeLoadString(L, code, chunk_name)) {
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);
+ lua_insert(L, -2);
return 2;
}
return 1;
int ScriptApiSecurity::sl_g_loadfile(lua_State *L)
{
- const char *path = NULL;
+#ifndef SERVER
+ lua_rawgeti(L, LUA_REGISTRYINDEX, CUSTOM_RIDX_SCRIPTAPI);
+#if INDIRECT_SCRIPTAPI_RIDX
+ ScriptApiBase *script = (ScriptApiBase *) *(void**)(lua_touserdata(L, -1));
+#else
+ ScriptApiBase *script = (ScriptApiBase *) lua_touserdata(L, -1);
+#endif
+ lua_pop(L, 1);
+ // Client implementation
+ if (script->getType() == ScriptingType::Client) {
+ std::string path = readParam<std::string>(L, 1);
+ const std::string *contents = script->getClient()->getModFile(path);
+ if (!contents) {
+ std::string error_msg = "Coudln't find script called: " + path;
+ lua_pushnil(L);
+ lua_pushstring(L, error_msg.c_str());
+ return 2;
+ }
+
+ std::string chunk_name = "@" + path;
+ if (!safeLoadString(L, *contents, chunk_name.c_str())) {
+ lua_pushnil(L);
+ lua_insert(L, -2);
+ return 2;
+ }
+ return 1;
+ }
+#endif
+
+ // Server implementation
+ const char *path = NULL;
if (lua_isstring(L, 1)) {
path = lua_tostring(L, 1);
- CHECK_SECURE_PATH(L, path);
+ CHECK_SECURE_PATH_INTERNAL(L, path, false, NULL);
}
if (!safeLoadFile(L, path)) {
size_t size;
const char *code = lua_tolstring(L, 1, &size);
+ std::string code_s(code, 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)) {
+ if (!safeLoadString(L, code_s, chunk_name)) {
lua_pushnil(L);
- lua_insert(L, lua_gettop(L) - 1);
+ lua_insert(L, -2);
return 2;
}
return 1;
int ScriptApiSecurity::sl_io_open(lua_State *L)
{
+ bool with_mode = lua_gettop(L) > 1;
+
luaL_checktype(L, 1, LUA_TSTRING);
const char *path = lua_tostring(L, 1);
- CHECK_SECURE_PATH(L, path);
+
+ bool write_requested = false;
+ if (with_mode) {
+ luaL_checktype(L, 2, LUA_TSTRING);
+ const char *mode = lua_tostring(L, 2);
+ write_requested = strchr(mode, 'w') != NULL ||
+ strchr(mode, '+') != NULL ||
+ strchr(mode, 'a') != NULL;
+ }
+ CHECK_SECURE_PATH_INTERNAL(L, path, write_requested, NULL);
push_original(L, "io", "open");
lua_pushvalue(L, 1);
- lua_pushvalue(L, 2);
- lua_call(L, 2, 2);
+ if (with_mode) {
+ lua_pushvalue(L, 2);
+ }
+
+ lua_call(L, with_mode ? 2 : 1, 2);
return 2;
}
{
if (lua_isstring(L, 1)) {
const char *path = lua_tostring(L, 1);
- CHECK_SECURE_PATH(L, path);
+ CHECK_SECURE_PATH_INTERNAL(L, path, false, NULL);
}
push_original(L, "io", "input");
{
if (lua_isstring(L, 1)) {
const char *path = lua_tostring(L, 1);
- CHECK_SECURE_PATH(L, path);
+ CHECK_SECURE_PATH_INTERNAL(L, path, true, NULL);
}
push_original(L, "io", "output");
{
if (lua_isstring(L, 1)) {
const char *path = lua_tostring(L, 1);
- CHECK_SECURE_PATH(L, path);
+ CHECK_SECURE_PATH_INTERNAL(L, path, false, NULL);
}
+ int top_precall = lua_gettop(L);
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);
+ return lua_gettop(L) - top_precall;
}
{
luaL_checktype(L, 1, LUA_TSTRING);
const char *path1 = lua_tostring(L, 1);
- CHECK_SECURE_PATH(L, path1);
+ CHECK_SECURE_PATH_INTERNAL(L, path1, true, NULL);
luaL_checktype(L, 2, LUA_TSTRING);
const char *path2 = lua_tostring(L, 2);
- CHECK_SECURE_PATH(L, path2);
+ CHECK_SECURE_PATH_INTERNAL(L, path2, true, NULL);
push_original(L, "os", "rename");
lua_pushvalue(L, 1);
{
luaL_checktype(L, 1, LUA_TSTRING);
const char *path = lua_tostring(L, 1);
- CHECK_SECURE_PATH(L, path);
+ CHECK_SECURE_PATH_INTERNAL(L, path, true, NULL);
push_original(L, "os", "remove");
lua_pushvalue(L, 1);
projects / dragonfireclient.git / blobdiff