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/*
* ModSecurity, http://www.modsecurity.org/
* Copyright (c) 2015 - 2021 Trustwave Holdings, Inc. (http://www.trustwave.com/)
*
* You may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* If any of the files related to licensing are missing or if you have any
* other questions related to licensing please contact Trustwave Holdings, Inc.
* directly using the email address security@modsecurity.org.
*
*/
#include "src/engine/lua.h"
#include <stdio.h>
#include <string.h>
#include <vector>
#include <string>
#include <algorithm>
#include <sstream>
#include <iterator>
#include <iostream>
#include "modsecurity/variable_value.h"
#include "modsecurity/modsecurity.h"
#include "src/utils/string.h"
#include "modsecurity/transaction.h"
#include "src/variables/variable.h"
#include "src/variables/highest_severity.h"
#include "src/actions/transformations/transformation.h"
namespace modsecurity {
namespace engine {
bool Lua::isCompatible(const std::string &script, Lua *l, std::string *error) {
#ifdef WITH_LUA
std::string lua(".lua");
std::string err;
if (!(script.size() >= lua.size() &&
script.compare(script.size() - lua.size(), lua.size(), lua) == 0)) {
error->assign("Expecting a Lua script: " + script);
return false;
}
if (l->load(script, &err) == false) {
error->assign("Problems load script: " + err);
return false;
}
return true;
#else
error->assign("Lua support was not enabled.");
return false;
#endif
}
bool Lua::load(const std::string &script, std::string *err) {
#ifdef WITH_LUA
lua_State *L = luaL_newstate();
luaL_openlibs(L);
m_scriptName = script;
if (luaL_loadfile(L, script.c_str())) {
const char *luaerr = lua_tostring(L, -1);
err->assign("Failed to compile script '" + script + "");
if (luaerr) {
err->append(": " + std::string(luaerr));
}
err->append(".");
lua_close(L);
return false;
}
#if defined (WITH_LUA_5_2) || defined (WITH_LUA_5_1)
if (lua_dump(L, Lua::blob_keeper, reinterpret_cast<void *>(&m_blob))) {
#else
if (lua_dump(L, Lua::blob_keeper, reinterpret_cast<void *>(&m_blob), 0)) {
#endif
const char *luaerr = lua_tostring(L, -1);
err->assign("Failed to compile script '" + script + "");
if (luaerr) {
err->append(": " + std::string(luaerr));
}
err->append(".");
lua_close(L);
return false;
}
lua_close(L);
return true;
#else
err->assign("Lua support was not enabled.");
return false;
#endif
}
#ifdef WITH_LUA
int Lua::blob_keeper(lua_State *L, const void *p, size_t sz, void *ud) {
LuaScriptBlob *lsb = static_cast<LuaScriptBlob *>(ud);
lsb->write(p, sz);
return 0;
}
const char *Lua::blob_reader(lua_State *L, void *ud, size_t *size) {
LuaScriptBlob *lsb = static_cast<LuaScriptBlob *>(ud);
const char *data = lsb->read(size);
return data;
}
#endif
int Lua::run(Transaction *t, const std::string &str) {
#ifdef WITH_LUA
std::string luaRet;
const char *a = NULL;
int ret = true;
lua_State *L = luaL_newstate();
luaL_openlibs(L);
luaL_newmetatable(L, "luaL_msc");
lua_newtable(L);
lua_pushlightuserdata(L, reinterpret_cast<void *>(t));
lua_setglobal(L, "__transaction");
luaL_setfuncs(L, mscLuaLib, 0);
lua_setglobal(L, "m");
#ifdef WITH_LUA_5_1
int rc = lua_load(L, Lua::blob_reader, &m_blob, m_scriptName.c_str());
#else
int rc = lua_load(L, Lua::blob_reader, &m_blob, m_scriptName.c_str(),
NULL);
#endif
if (rc != LUA_OK) {
std::string e;
e.assign("Failed to execute lua script: " + m_scriptName + ". ");
switch (rc) {
case LUA_ERRSYNTAX:
e.assign("Syntax error. ");
break;
case LUA_ERRMEM:
e.assign("Memory error. ");
break;
#if !defined(WITH_LUA_5_1) and !defined(WITH_LUA_5_4)
case LUA_ERRGCMM:
e.assign("Garbage Collector error. ");
break;
#endif
}
e.append(lua_tostring(L, -1));
ms_dbg_a(t, 2, e);
ret = false;
goto err;
}
if (lua_pcall(L, 0, 0, 0)) {
std::string e;
const char *luaerr = lua_tostring(L, -1);
e.assign("Failed to execute lua script: " + m_scriptName \
+ " (before main)");
if (luaerr != NULL) {
e.append(" - ");
e.append(luaerr);
}
ms_dbg_a(t, 2, e);
ret = false;
goto err;
}
lua_setglobal(L, "modsec");
lua_getglobal(L, "main");
ms_dbg_a(t, 1, str);
/* Put the parameter on the stack. */
if (!str.empty() ) {
lua_pushlstring(L, str.c_str(), str.length());
}
if (lua_pcall(L, ((!str.empty()) ? 1 : 0), 1, 0)) {
std::string e;
const char *luaerr = lua_tostring(L, -1);
e.assign("Failed to execute lua script: " + m_scriptName + " (main)");
if (luaerr != NULL) {
e.append(" - ");
e.append(luaerr);
}
ms_dbg_a(t, 2, e);
ret = false;
goto err;
}
a = reinterpret_cast<const char *>(lua_tostring(L, -1));
if (a != NULL) {
luaRet.assign(a);
}
ms_dbg_a(t, 9, "Returning from lua script: " + luaRet);
if (luaRet.size() == 0) {
ret = false;
}
err:
lua_pop(L, 1);
lua_close(L);
return ret;
#else
ms_dbg_a(t, 9, "Lua support was not enabled.");
return false;
#endif
}
#ifdef WITH_LUA
int Lua::log(lua_State *L) {
const Transaction *t(NULL);
const char *text;
int level;
/* Retrieve parameters. */
level = luaL_checknumber(L, 1);
text = luaL_checkstring(L, 2);
/* Retrieve msr. */
lua_getglobal(L, "__transaction");
t = reinterpret_cast<const Transaction *>(lua_topointer(L, -1));
/* Log message. */
if (t != NULL) {
ms_dbg_a(t, level, text);
}
return 0;
}
int Lua::getvar(lua_State *L) {
const char *varname(NULL);
Transaction *t(NULL);
void *z(NULL);
/* Retrieve parameters. */
varname = reinterpret_cast<const char *>(luaL_checkstring(L, 1));
lua_getglobal(L, "__transaction");
z = const_cast<void *>(lua_topointer(L, -1));
t = reinterpret_cast<Transaction *>(z);
std::string var = variables::Variable::stringMatchResolve(t, varname);
var = applyTransformations(L, t, 2, var);
if (var.size() == 0) {
lua_pushnil(L);
return 0;
}
lua_pushlstring(L, var.c_str(), var.size());
return 1;
}
int Lua::getvars(lua_State *L) {
const char *varname(NULL);
Transaction *t(NULL);
void *z(NULL);
std::vector<const VariableValue *> l;
int idx = 1;
/* Retrieve parameters. */
varname = reinterpret_cast<const char *>(luaL_checkstring(L, 1));
lua_getglobal(L, "__transaction");
z = const_cast<void *>(lua_topointer(L, -1));
t = reinterpret_cast<Transaction *>(z);
variables::Variable::stringMatchResolveMulti(t, varname, &l);
lua_newtable(L);
for (auto i : l) {
lua_pushnumber(L, idx);
lua_newtable(L);
lua_pushstring(L, "name");
lua_pushlstring(L, i->getKeyWithCollection().c_str(), i->getKeyWithCollection().size());
lua_settable(L, -3);
lua_pushstring(L, "value");
lua_pushlstring(L, i->getValue().c_str(), i->getValue().size());
lua_settable(L, -3);
lua_settable(L, -3);
idx++;
}
for (const VariableValue * i : l) {
delete i;
}
return 1;
}
int Lua::setvar(lua_State *L) {
Transaction *t(NULL);
const char *var_value(NULL);
const char *var_name(NULL);
std::string vname;
std::string collection;
std::string variableName;
int nargs = lua_gettop(L);
char *chr = NULL;
size_t pos;
void *z(NULL);
lua_getglobal(L, "__transaction");
z = const_cast<void *>(lua_topointer(L, -1));
t = reinterpret_cast<Transaction *>(z);
if (nargs != 2) {
ms_dbg_a(t, 8,
"m.setvar: Failed m.setvar funtion must has 2 arguments");
return -1;
}
var_value = luaL_checkstring(L, 2);
var_name = luaL_checkstring(L, 1);
lua_pop(L, 2);
if (var_value == NULL || var_name == NULL) {
return -1;
}
vname.assign(var_name);
pos = vname.find(".");
if (pos != std::string::npos) {
collection = std::string(vname, 0, pos);
collection = utils::string::toupper(collection);
variableName = std::string(vname, pos + 1,
std::string::npos);
} else {
ms_dbg_a(t, 8,
"m.setvar: Must specify a collection using dot character" \
" - ie m.setvar(tx.myvar,mydata)");
return -1;
}
if (collection == "TX") {
t->m_collections.m_tx_collection->storeOrUpdateFirst(
variableName,
var_value);
}
else if (collection == "IP") {
t->m_collections.m_ip_collection->storeOrUpdateFirst(
variableName, t->m_collections.m_ip_collection_key,
t->m_rules->m_secWebAppId.m_value,
var_value);
}
else if (collection == "GLOBAL") {
t->m_collections.m_global_collection->storeOrUpdateFirst(
variableName, t->m_collections.m_global_collection_key,
t->m_rules->m_secWebAppId.m_value,
var_value);
}
else if (collection == "RESOURCE") {
t->m_collections.m_resource_collection->storeOrUpdateFirst(
variableName,
t->m_collections.m_resource_collection_key,
t->m_rules->m_secWebAppId.m_value,
var_value);
}
else if (collection == "SESSION") {
t->m_collections.m_session_collection->storeOrUpdateFirst(
variableName, t->m_collections.m_session_collection_key,
t->m_rules->m_secWebAppId.m_value,
var_value);
}
else if (collection == "USER") {
t->m_collections.m_user_collection->storeOrUpdateFirst(
variableName, t->m_collections.m_user_collection_key,
t->m_rules->m_secWebAppId.m_value,
var_value);
}
return 0;
}
std::string Lua::applyTransformations(lua_State *L, Transaction *t,
int idx, std::string var) {
std::string newVar = var;
if (lua_isuserdata(L, idx) || lua_isnoneornil(L, idx)) {
return var;
}
if (lua_istable(L, idx)) {
const char *name = NULL;
#ifdef WITH_LUA_5_1
int i, n = lua_objlen(L, idx);
#else
int i, n = lua_rawlen(L, idx);
#endif
for (i = 1; i <= n; i++) {
lua_rawgeti(L, idx, i);
name = reinterpret_cast<const char *>(luaL_checkstring(L, -1));
/* A "none" means start over */
if (strcmp("none", name) == 0) {
newVar = var;
continue;
}
actions::transformations::Transformation *tfn = \
actions::transformations::Transformation::instantiate(
"t:" + std::string(name));
// FIXME: transformation is not yet returning null.
if (tfn) {
newVar = tfn->evaluate(newVar, t);
} else {
ms_dbg_a(t, 1,
"SecRuleScript: Invalid transformation function: " \
+ std::string(name));
}
delete tfn;
}
return newVar;
}
if (lua_isstring(L, idx)) {
const char *name(NULL);
name = reinterpret_cast<const char *>(luaL_checkstring(L, idx));
actions::transformations::Transformation *tfn = \
actions::transformations::Transformation::instantiate(
"t:" + std::string(name));
// FIXME: transformation is not yet returning null.
if (tfn) {
newVar = tfn->evaluate(newVar, t);
delete tfn;
} else {
ms_dbg_a(t, 1, "SecRuleScript: Invalid transformation function: " \
+ std::string(name));
}
return newVar;
}
ms_dbg_a(t, 8, "SecRuleScript: Transformation parameter must be a " \
"transformation name or array of transformation names, but found " \
"" + std::string(lua_typename(L, idx)) + " (type " \
+ std::to_string(lua_type(L, idx)) + ")");
return newVar;
}
#endif
} // namespace engine
} // namespace modsecurity