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suricata/src/util-lua-bytevarlib.c

128 lines
3.6 KiB
C

/* Copyright (C) 2025 Open Information Security Foundation
*
* You can copy, redistribute or modify this Program under the terms of
* the GNU General Public License version 2 as published by the Free
* Software Foundation.
*
* 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* version 2 along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*/
#include "suricata-common.h"
#include "detect-byte.h"
#include "util-lua-common.h"
#include "util-lua-bytevarlib.h"
#include "util-lua.h"
#include "detect-lua.h"
#include "detect-lua-extensions.h"
#include "lauxlib.h"
static const char suricata_bytevar_mt[] = "suricata:bytevar:mt";
static DetectLuaData *GetLuaData(lua_State *luastate)
{
DetectLuaData *ld;
lua_pushlightuserdata(luastate, (void *)&luaext_key_ld);
lua_gettable(luastate, LUA_REGISTRYINDEX);
ld = lua_touserdata(luastate, -1);
return ld;
}
static int LuaBytevarMap(lua_State *L)
{
const Signature *s = lua_touserdata(L, -2);
const char *name = luaL_checkstring(L, -1);
DetectLuaData *ld = GetLuaData(L);
/* Is this name already mapped? */
for (uint16_t i = 0; i < ld->bytevars; i++) {
if (strcmp(ld->bytevar[i].name, name) == 0) {
lua_pushinteger(L, ld->bytevar[i].id);
return 1;
}
}
if (ld->bytevars == DETECT_LUA_MAX_BYTEVARS) {
luaL_error(L, "too many bytevars mapped");
}
DetectByteIndexType idx;
if (!DetectByteRetrieveSMVar(name, s, &idx)) {
luaL_error(L, "unknown byte_extract or byte_math variable: %s", name);
}
ld->bytevar[ld->bytevars].name = SCStrdup(name);
if (ld->bytevar[ld->bytevars].name == NULL) {
luaL_error(L, "failed to allocate memory for bytevar name: %s", name);
}
ld->bytevar[ld->bytevars++].id = idx;
return 1;
}
static int LuaBytevarGet(lua_State *L)
{
const char *name = luaL_checkstring(L, 1);
DetectLuaData *ld = GetLuaData(L);
if (ld == NULL) {
return luaL_error(L, "internal error: no lua data");
}
for (uint16_t i = 0; i < ld->bytevars; i++) {
if (strcmp(ld->bytevar[i].name, name) == 0) {
uint32_t *bytevar_id = lua_newuserdata(L, sizeof(*bytevar_id));
*bytevar_id = ld->bytevar[i].id;
luaL_getmetatable(L, suricata_bytevar_mt);
lua_setmetatable(L, -2);
return 1;
}
}
return luaL_error(L, "unknown bytevar: %s", name);
}
static int LuaBytevarValue(lua_State *L)
{
uint32_t *bytevar_id = luaL_checkudata(L, 1, suricata_bytevar_mt);
DetectEngineThreadCtx *det_ctx = LuaStateGetDetCtx(L);
if (det_ctx == NULL) {
return LuaCallbackError(L, "internal error: no det_ctx");
}
lua_pushinteger(L, det_ctx->byte_values[*bytevar_id]);
return 1;
}
static const luaL_Reg bytevarlib[] = {
// clang-format off
{ "map", LuaBytevarMap, },
{ "get", LuaBytevarGet, },
{ NULL, NULL, },
// clang-format on
};
static const luaL_Reg bytevarmt[] = {
// clang-format off
{ "value", LuaBytevarValue, },
{ NULL, NULL, },
// clang-format on
};
int LuaLoadBytevarLib(lua_State *L)
{
luaL_newmetatable(L, suricata_bytevar_mt);
lua_pushvalue(L, -1);
lua_setfield(L, -2, "__index");
luaL_setfuncs(L, bytevarmt, 0);
luaL_newlib(L, bytevarlib);
return 1;
}