Re: Nonblocking script execution

[David Given <dg@...>]

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Alexander Gladysh wrote:
[...]
> ("xyzzy"):rep(1e7):gsub("(z+)", "Z")
> 
> This one takes 4 seconds on my box, and has just 9 instructions.
> 
> While one can take away IO from untrusted code, string library is
> usually a requirement...

Of course, this *does* use an unreasonable amount of memory, which in
such an environment is probably going to managed (apart from anything
else, Lua makes this very easy).

It's an important point, though. I wonder what the *most* malicious code
it's possible to write in a instruction-and-memory-limited Lua VM,
assuming no IO, of course? Could you, for example, persuade gsub to
continuously insert an empty string, or something similar?

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