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main ... 1.31.1

Author SHA1 Message Date
Peter Hutterer
1920686963 libinput 1.31.1
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
2026-04-02 11:04:12 +10:00
Peter Hutterer
49f9a81517 lua: force text mode for loading plugins
luaL_loadfile() by default allows for both text files and precompiled
lua files. Precompiled files are not verified on load allowing for a
sandbox escape.

CVE-2026-35093

Fixes: #1271

Found-by: Koen Tange <koen@monokles.eu>

(cherry picked from commit 356c498fd4)

Part-of: <https://gitlab.freedesktop.org/libinput/libinput/-/merge_requests/1461>
2026-04-02 10:18:00 +10:00
Peter Hutterer
45506c7b3c lua: separate the API from the metatables
Previously we had one vtable for the libinputplugin and EvdevDevice
objects. This allowed plugins to call __gc(), a decidedly internal
method.

This fixes a use-after-free: A plugin that called EvdevDevice::__gc()
frees the plugin's copy of device->name but leaves the pointer in-place,
a subsequent call will thus cause a UAF read.

Fix this by separating what is the object's metatable from the public
methods that are accessible to a plugin.

CVE-2026-35094

Fixes: #1272

Found-by: Koen Tange <koen@monokles.eu>

(cherry picked from commit 45dfd0f030)

Part-of: <https://gitlab.freedesktop.org/libinput/libinput/-/merge_requests/1461>
2026-04-02 10:17:52 +10:00
3 changed files with 144 additions and 16 deletions

View file

@ -1,5 +1,5 @@
project('libinput', 'c',
version : '1.31.0',
version : '1.31.1',
license : 'MIT/Expat',
default_options : [ 'c_std=gnu99', 'warning_level=2' ],
meson_version : '>= 0.64.0')

View file

@ -562,6 +562,12 @@ libinputplugin_unregister(lua_State *L)
return luaL_error(L, "@@unregistering@@");
}
static int
readonly_newindex(lua_State *L)
{
return luaL_error(L, "attempt to modify a read-only table");
}
static int
libinputplugin_gc(lua_State *L)
{
@ -673,7 +679,28 @@ libinputplugin_log_error(lua_State *L)
return libinputplugin_log(L, LIBINPUT_LOG_PRIORITY_ERROR);
}
static const struct luaL_Reg libinputplugin_vtable[] = {
static void
setup_vfuncs(lua_State *L,
const char *metatable_name,
const struct luaL_Reg *vfuncs,
const struct luaL_Reg *public_methods)
{
luaL_newmetatable(L, metatable_name);
luaL_setfuncs(L, vfuncs, 0);
lua_newtable(L);
luaL_setfuncs(L, public_methods, 0);
lua_setfield(L, -2, "__index");
/* set metatable.__metatable = false to prevent a script from getmetatable(),
which is blocked anyway but safe and sorry and whatnot */
lua_pushboolean(L, 0);
lua_setfield(L, -2, "__metatable");
lua_pop(L, 1);
}
static const struct luaL_Reg libinputplugin_methods[] = {
{ "now", libinputplugin_now },
{ "version", libinputplugin_version },
{ "connect", libinputplugin_connect },
@ -685,18 +712,18 @@ static const struct luaL_Reg libinputplugin_vtable[] = {
{ "log_debug", libinputplugin_log_debug },
{ "log_info", libinputplugin_log_info },
{ "log_error", libinputplugin_log_error },
{ "__gc", libinputplugin_gc },
{ NULL, NULL }
};
static const struct luaL_Reg libinputplugin_meta[] = { { "__gc", libinputplugin_gc },
{ "__newindex",
readonly_newindex },
{ NULL, NULL } };
static void
libinputplugin_init(lua_State *L)
{
luaL_newmetatable(L, PLUGIN_METATABLE);
lua_pushstring(L, "__index");
lua_pushvalue(L, -2); /* push metatable */
lua_settable(L, -3); /* metatable.__index = metatable */
luaL_setfuncs(L, libinputplugin_vtable, 0);
setup_vfuncs(L, PLUGIN_METATABLE, libinputplugin_meta, libinputplugin_methods);
}
static int
@ -1073,7 +1100,7 @@ evdevdevice_gc(lua_State *L)
return 0;
}
static const struct luaL_Reg evdevdevice_vtable[] = {
static const struct luaL_Reg evdevdevice_methods[] = {
{ "info", evdevdevice_info },
{ "name", evdevdevice_name },
{ "usages", evdevdevice_usages },
@ -1087,18 +1114,17 @@ static const struct luaL_Reg evdevdevice_vtable[] = {
{ "prepend_frame", evdevdevice_prepend_frame },
{ "append_frame", evdevdevice_append_frame },
{ "disable_feature", evdevdevice_disable_feature },
{ "__gc", evdevdevice_gc },
{ NULL, NULL }
};
static const struct luaL_Reg evdevdevice_meta[] = { { "__gc", evdevdevice_gc },
{ "__newindex", readonly_newindex },
{ NULL, NULL } };
static void
evdevdevice_init(lua_State *L)
{
luaL_newmetatable(L, EVDEV_DEVICE_METATABLE);
lua_pushstring(L, "__index");
lua_pushvalue(L, -2); /* push metatable */
lua_settable(L, -3); /* metatable.__index = metatable */
luaL_setfuncs(L, evdevdevice_vtable, 0);
setup_vfuncs(L, EVDEV_DEVICE_METATABLE, evdevdevice_meta, evdevdevice_methods);
}
static void
@ -1336,7 +1362,7 @@ libinput_lua_plugin_new_from_path(struct libinput *libinput, const char *path)
return NULL;
}
int ret = luaL_loadfile(L, path);
int ret = luaL_loadfilex(L, path, "t");
if (ret == LUA_OK) {
plugin->L = steal(&L);

View file

@ -526,6 +526,38 @@ START_TEST(lua_disallowed_functions)
}
END_TEST
START_TEST(lua_gc_not_accessible)
{
_destroy_(tmpdir) *tmpdir = tmpdir_create(NULL);
const char *lua =
"libinput:register({1})\n"
"assert(libinput.__gc == nil)\n"
"function check_device_gc(device)\n"
" assert(device.__gc == nil)\n"
" libinput:log_info(\"gc_not_accessible: ok\")\n"
"end\n"
"libinput:connect(\"new-evdev-device\", check_device_gc)\n";
_autofree_ char *path = litest_write_plugin(tmpdir->path, lua);
_litest_context_destroy_ struct libinput *li =
litest_create_context_with_plugindir(tmpdir->path);
if (libinput_log_get_priority(li) > LIBINPUT_LOG_PRIORITY_INFO)
libinput_log_set_priority(li, LIBINPUT_LOG_PRIORITY_INFO);
litest_with_logcapture(li, capture) {
libinput_plugin_system_load_plugins(li,
LIBINPUT_PLUGIN_SYSTEM_FLAG_NONE);
litest_drain_events(li);
_destroy_(litest_device) *device = litest_add_device(li, LITEST_MOUSE);
litest_drain_events(li);
litest_assert_logcapture_no_errors(capture);
litest_assert_strv_substring(capture->infos, "gc_not_accessible: ok");
}
}
END_TEST
START_TEST(lua_frame_handler)
{
_destroy_(tmpdir) *tmpdir = tmpdir_create(NULL);
@ -1172,10 +1204,79 @@ START_TEST(lua_remove_plugin_on_timeout)
}
END_TEST
/* Pre-compiled Lua 5.4 bytecode for the following source:
*
* libinput:register({1})
* libinput:connect("new-evdev-device", function(device)
* libinput:log_info("loaded from binary lua file")
* end)
*
* To regenerate:
* luac5.4 -o /dev/stdout /tmp/plugin.lua | xxd -i
*/
static const unsigned char binary_lua_plugin[] = {
0x1b, 0x4c, 0x75, 0x61, 0x54, 0x00, 0x19, 0x93, 0x0d, 0x0a, 0x1a, 0x0a, 0x04,
0x08, 0x08, 0x78, 0x56, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x28, 0x77, 0x40, 0x01, 0x9b, 0x40, 0x74, 0x65, 0x73, 0x74, 0x2f,
0x31, 0x30, 0x2d, 0x62, 0x69, 0x6e, 0x61, 0x72, 0x79, 0x2d, 0x70, 0x6c, 0x75,
0x67, 0x69, 0x6e, 0x2e, 0x6c, 0x75, 0x61, 0x80, 0x80, 0x00, 0x01, 0x04, 0x8e,
0x51, 0x00, 0x00, 0x00, 0x0b, 0x00, 0x00, 0x00, 0x14, 0x80, 0x00, 0x01, 0x13,
0x01, 0x00, 0x01, 0x52, 0x00, 0x00, 0x00, 0x81, 0x01, 0x00, 0x80, 0x4e, 0x01,
0x01, 0x00, 0x44, 0x00, 0x03, 0x01, 0x0b, 0x00, 0x00, 0x00, 0x14, 0x80, 0x00,
0x02, 0x03, 0x81, 0x01, 0x00, 0xcf, 0x01, 0x00, 0x00, 0x44, 0x00, 0x04, 0x01,
0x46, 0x00, 0x01, 0x01, 0x84, 0x04, 0x89, 0x6c, 0x69, 0x62, 0x69, 0x6e, 0x70,
0x75, 0x74, 0x04, 0x89, 0x72, 0x65, 0x67, 0x69, 0x73, 0x74, 0x65, 0x72, 0x04,
0x88, 0x63, 0x6f, 0x6e, 0x6e, 0x65, 0x63, 0x74, 0x04, 0x91, 0x6e, 0x65, 0x77,
0x2d, 0x65, 0x76, 0x64, 0x65, 0x76, 0x2d, 0x64, 0x65, 0x76, 0x69, 0x63, 0x65,
0x81, 0x01, 0x00, 0x00, 0x81, 0x80, 0x8d, 0x8f, 0x01, 0x00, 0x04, 0x85, 0x8b,
0x00, 0x00, 0x00, 0x94, 0x80, 0x01, 0x01, 0x83, 0x01, 0x01, 0x00, 0xc4, 0x00,
0x03, 0x01, 0xc7, 0x00, 0x01, 0x00, 0x83, 0x04, 0x89, 0x6c, 0x69, 0x62, 0x69,
0x6e, 0x70, 0x75, 0x74, 0x04, 0x89, 0x6c, 0x6f, 0x67, 0x5f, 0x69, 0x6e, 0x66,
0x6f, 0x04, 0x9c, 0x6c, 0x6f, 0x61, 0x64, 0x65, 0x64, 0x20, 0x66, 0x72, 0x6f,
0x6d, 0x20, 0x62, 0x69, 0x6e, 0x61, 0x72, 0x79, 0x20, 0x6c, 0x75, 0x61, 0x20,
0x66, 0x69, 0x6c, 0x65, 0x81, 0x00, 0x00, 0x00, 0x80, 0x85, 0x01, 0x00, 0x00,
0x00, 0x01, 0x80, 0x81, 0x87, 0x64, 0x65, 0x76, 0x69, 0x63, 0x65, 0x80, 0x85,
0x81, 0x85, 0x5f, 0x45, 0x4e, 0x56, 0x8e, 0x01, 0x0b, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x01, 0x00, 0x00, 0x02, 0xfe, 0x02, 0x80, 0x80, 0x81, 0x85, 0x5f,
0x45, 0x4e, 0x56,
};
START_TEST(lua_reject_precompiled_files)
{
_destroy_(tmpdir) *tmpdir = tmpdir_create(NULL);
/* Write the binary bytecode to a .lua file in the tmpdir.
* Binary (pre-compiled) Lua files must be rejected by the
* plugin loader for security reasons. */
_autofree_ char *path = strdup_printf("%s/10-binary-plugin.lua", tmpdir->path);
_autoclose_ int fd = open(path, O_WRONLY | O_CREAT, 0644);
litest_assert_errno_success(fd);
ssize_t written = write(fd, binary_lua_plugin, sizeof(binary_lua_plugin));
litest_assert_int_eq((int)written, (int)sizeof(binary_lua_plugin));
fsync(fd);
_litest_context_destroy_ struct libinput *li =
litest_create_context_with_plugindir(tmpdir->path);
litest_with_logcapture(li, capture) {
libinput_plugin_system_load_plugins(li,
LIBINPUT_PLUGIN_SYSTEM_FLAG_NONE);
litest_drain_events(li);
size_t index = 0;
litest_assert(
strv_find_substring(capture->errors, "Failed to load", &index));
litest_assert_str_in(path, capture->errors[index]);
}
}
END_TEST
TEST_COLLECTION(lua)
{
/* clang-format off */
litest_add_no_device(lua_load_failure);
litest_add_no_device(lua_reject_precompiled_files);
litest_with_parameters(params,
"content", 'I', 6,
litest_named_i32(EMPTY),
@ -1219,6 +1320,7 @@ TEST_COLLECTION(lua)
litest_add_no_device(lua_register_multiversions);
litest_add_no_device(lua_allowed_functions);
litest_add_no_device(lua_disallowed_functions);
litest_add_no_device(lua_gc_not_accessible);
litest_add_no_device(lua_frame_handler);
litest_add_no_device(lua_device_info);