blocking some io functions

cmd/packets/main.go

@@ -537,6 +537,7 @@ func Install(packagepath string, serial uint) error {
 	defer L.Close()
 
 	osObject := L.GetGlobal("os").(*lua.LTable)
+	ioObject := L.GetGlobal("io").(*lua.LTable)
 
 	L.SetGlobal("packets_package_dir", lua.LString(cfg.Config.DataDir))
 	L.SetGlobal("packets_bin_dir", lua.LString(cfg.Config.BinDir))
@@ -547,6 +548,17 @@ func Install(packagepath string, serial uint) error {
 	osObject.RawSetString("remove", L.NewFunction(internal.SafeRemove))
 	osObject.RawSetString("rename", L.NewFunction(internal.SafeRename))
 	osObject.RawSetString("copy", L.NewFunction(internal.SafeCopy))
+	osObject.RawSetString("symlink", L.NewFunction(internal.SymbolicLua))
+
+	ioObject.RawSetString("input", lua.LNil)
+	ioObject.RawSetString("output", lua.LNil)
+	ioObject.RawSetString("popen", lua.LNil)
+	ioObject.RawSetString("tmpfile", lua.LNil)
+	ioObject.RawSetString("stdout", lua.LNil)
+	ioObject.RawSetString("stdeer", lua.LNil)
+	ioObject.RawSetString("stdin", lua.LNil)
+	ioObject.RawSetString("lines", lua.LNil)
+	ioObject.RawSetString("open", L.NewFunction(internal.SafeOpen))
 
 	if err := L.DoFile(manifest.Hooks.Install); err != nil {
 		log.Panic(err)

internal/internal.go

@@ -282,3 +282,71 @@ func SafeCopy(L *lua.LState) int {
 	L.Push(lua.LNil)
 	return 2
 }
+
+func SymbolicLua(L *lua.LState) int {
+	fileName := L.CheckString(1)
+	destination := L.CheckString(2)
+
+	if !IsSafe(fileName) || !IsSafe(destination) {
+		L.Push(lua.LFalse)
+		L.Push(lua.LString("[packets] unsafe filepath"))
+		return 2
+	}
+
+	if err := os.Symlink(fileName, destination); err != nil {
+		L.Push(lua.LFalse)
+		L.Push(lua.LString("[packets] symlink failed\n" + err.Error()))
+	}
+
+	L.Push(lua.LTrue)
+	L.Push(lua.LNil)
+	return 2
+}
+
+func modeFlags(mode string) int {
+	switch mode {
+	case "r", "rb":
+		return os.O_RDONLY
+	case "w", "wb":
+		return os.O_CREATE | os.O_WRONLY | os.O_TRUNC
+	case "a", "ab":
+		return os.O_CREATE | os.O_WRONLY | os.O_APPEND
+	case "r+", "r+b", "rb+", "br+":
+		return os.O_RDWR
+	case "w+", "w+b", "wb+", "bw+":
+		return os.O_CREATE | os.O_RDWR | os.O_TRUNC
+	case "a+", "a+b", "ab+", "ba+":
+		return os.O_CREATE | os.O_RDWR | os.O_APPEND
+	default:
+		return os.O_RDONLY
+	}
+}
+
+func SafeOpen(L *lua.LState) int {
+	path := L.CheckString(1)
+	mode := L.OptString(2, "r")
+
+	if !IsSafe(path) {
+		L.Push(lua.LNil)
+		L.Push(lua.LString("[packets] unsafe filepath"))
+		return 2
+	}
+	file, err := os.OpenFile(path, modeFlags(mode), 0644)
+	if err != nil {
+		L.Push(lua.LNil)
+		L.Push(lua.LString(err.Error()))
+		return 2
+	}
+
+	ud := L.NewUserData()
+	ud.Value = file
+	L.SetMetatable(ud, L.GetTypeMetatable("file"))
+	L.Push(ud)
+	L.Push(lua.LNil)
+	return 2
+}
+
+func safeLines(L *lua.LState) int {
+
+	return 2
+}