mirror of
https://gitlab.freedesktop.org/pipewire/wireplumber.git
synced 2025-12-20 13:30:04 +01:00
15f5f96693
The only secure and robust way to check that a userdata is of the expected type is to check its metatable. Userdata metatables are not changeable by Lua code without the debug library, so if the metatable is a certain table, only C code could have made it so. GLib type checking functions are _not_ a robust or secure way to check that a block of memory is a specific type of GObject, because Lua code could cause a type confusion bug and potentially use it to forge pointers.
116 lines
2.8 KiB
C
116 lines
2.8 KiB
C
/* WirePlumber
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*
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* Copyright © 2020 Collabora Ltd.
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* @author George Kiagiadakis <george.kiagiadakis@collabora.com>
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*
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* SPDX-License-Identifier: MIT
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*/
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#include "wplua.h"
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#include "private.h"
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#include <wp/wp.h>
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static lua_CFunction
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find_method_in_luaL_Reg (luaL_Reg *reg, const gchar *method)
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{
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if (reg) {
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while (reg->name) {
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if (!g_strcmp0 (method, reg->name))
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return reg->func;
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reg++;
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}
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}
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return NULL;
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}
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static int
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_wplua_gboxed___index (lua_State *L)
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{
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GValue *obj_v = _wplua_togvalue_userdata_named (L, 1, G_TYPE_BOXED, "GBoxed");
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luaL_argcheck (L, obj_v != NULL, 1,
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"expected userdata storing GValue<GBoxed>");
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const gchar *key = luaL_checkstring (L, 2);
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GType type = G_VALUE_TYPE (obj_v);
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lua_CFunction func = NULL;
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GHashTable *vtables;
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lua_pushliteral (L, "wplua_vtables");
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lua_gettable (L, LUA_REGISTRYINDEX);
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vtables = wplua_toboxed (L, -1);
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lua_pop (L, 1);
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/* search in registered vtables */
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while (!func && type) {
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luaL_Reg *reg = g_hash_table_lookup (vtables, GUINT_TO_POINTER (type));
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func = find_method_in_luaL_Reg (reg, key);
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type = g_type_parent (type);
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}
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wp_trace_boxed (type, g_value_get_boxed (obj_v),
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"indexing GBoxed, looking for '%s', found: %p", key, func);
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if (func) {
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lua_pushcfunction (L, func);
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return 1;
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}
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return 0;
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}
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static int
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_wplua_gboxed___eq (lua_State *L)
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{
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return _wplua_gvalue_userdata___eq_impl (L, "GBoxed");
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}
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void
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_wplua_init_gboxed (lua_State *L)
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{
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static const luaL_Reg gboxed_meta[] = {
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{ "__gc", _wplua_gvalue_userdata___gc },
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{ "__eq", _wplua_gboxed___eq },
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{ "__index", _wplua_gboxed___index },
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{ NULL, NULL }
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};
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if (!luaL_newmetatable (L, "GBoxed"))
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g_error ("Metatable with key GBoxed in the registry already exists?");
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luaL_setfuncs (L, gboxed_meta, 0);
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lua_pop (L, 1);
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}
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void
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wplua_pushboxed (lua_State * L, GType type, gpointer object)
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{
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g_return_if_fail (G_TYPE_FUNDAMENTAL (type) == G_TYPE_BOXED);
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GValue *v = _wplua_pushgvalue_userdata (L, type);
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wp_trace_boxed (type, object, "pushing to Lua, v=%p", v);
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g_value_take_boxed (v, object);
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}
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gpointer
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wplua_toboxed (lua_State *L, int idx)
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{
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GValue *v = _wplua_togvalue_userdata_named (L, idx, G_TYPE_BOXED, "GBoxed");
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g_return_val_if_fail (v, NULL);
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return g_value_get_boxed (v);
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}
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gpointer
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wplua_checkboxed (lua_State *L, int idx, GType type)
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{
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GValue *v = _wplua_togvalue_userdata_named (L, idx, type, "GBoxed");
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if (v == NULL) {
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wp_critical ("expected userdata storing GValue<%s>", g_type_name (type));
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luaL_argerror (L, idx, "expected userdata storing GValue<GBoxed>");
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}
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return g_value_get_boxed (v);
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}
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gboolean
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wplua_isboxed (lua_State *L, int idx, GType type)
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{
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return g_type_is_a (type, G_TYPE_BOXED) &&
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_wplua_togvalue_userdata_named (L, idx, type, "GBoxed") != NULL;
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}
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