wehub-resource-sync
51 lines
1.7 KiB
Go
51 lines
1.7 KiB
Go
package luaplugin
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import lua "github.com/yuin/gopher-lua"
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// Sandbox applies the plugin sandbox to L. It is exported for tools that load
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// plugin files outside the runtime (e.g. pluginmgr metadata extraction) and
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// must apply the same stdlib restrictions before executing untrusted code.
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func Sandbox(L *lua.LState) { sandbox(L) }
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// sandbox removes dangerous Lua standard library functions from the VM,
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// leaving only safe operations available to plugins. It also adds
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// compatibility helpers missing from Lua 5.1 (e.g. utf8.char).
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func sandbox(L *lua.LState) {
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// Remove top-level functions that can load/execute arbitrary code.
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for _, name := range []string{"dofile", "loadfile", "load", "loadstring", "require", "module"} {
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L.SetGlobal(name, lua.LNil)
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}
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L.SetGlobal("package", lua.LNil)
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L.SetGlobal("debug", lua.LNil)
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// Remove the io module entirely (replaced by cliamp.fs).
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L.SetGlobal("io", lua.LNil)
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// Restrict the os module to a safe subset: time, date, clock, getenv.
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if os := L.GetGlobal("os"); os != lua.LNil {
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if tbl, ok := os.(*lua.LTable); ok {
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for _, fn := range []string{"execute", "remove", "rename", "exit", "setlocale", "tmpname"} {
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tbl.RawSetString(fn, lua.LNil)
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}
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}
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}
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// Provide utf8.char() for Lua 5.1 compatibility (GopherLua is 5.1).
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// Plugins need this for Braille character rendering in visualizers.
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utf8Tbl := L.NewTable()
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L.SetField(utf8Tbl, "char", L.NewFunction(luaUTF8Char))
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L.SetGlobal("utf8", utf8Tbl)
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}
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// luaUTF8Char converts one or more integer codepoints to a UTF-8 string.
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// Equivalent to Lua 5.3's utf8.char().
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func luaUTF8Char(L *lua.LState) int {
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n := L.GetTop()
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buf := make([]rune, n)
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for i := 1; i <= n; i++ {
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buf[i-1] = rune(L.CheckInt(i))
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}
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L.Push(lua.LString(string(buf)))
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return 1
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}
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