Re: Reentrant GC

[Pierre Chapuis <catwell@...>]

On Tue, Nov 27, 2018, at 10:29, Soni L. wrote:

I am concerned about an attacker setting a __gc metamethod that loops forever and can't be broken.

So this is more about debug hooks not running during `__gc` then?

This is a very real problem that has existed for a very long time [1].

I don't know another solution than not allowing untrusted users to set `__gc`.

All sandboxes I know about (including those implemented in C) that do and

don't do something very violent like spawning a thread and killing it after some

time when unresponsive are somehow vulnerable to this.

[1] https://github.com/lua/lua/commit/6c79a0a80d517354dcc19a1ef64569fba9b19365#diff-8ea37271806c5efe3d7bbb83e67046d1R244

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Pierre Chapuis