[girvel]

I looked into it, and Lua allows limiting the environment when `load`ing -- through `env` argument since 5.2 or through setfenv before. I will add a helper function to produce a minimal needed environment for safe loading and a documentation page about safety.

[myrmidon]

Note that loading (maliciously crafted) bytecode is generally not safe in Lua; sandboxing can be escaped in more ways than what's possible when loading plaintext sourcecode, and there are no full mitigations for this currently as far as I know (and would probably be highly interpreter/version sensitive anyway)-- the only "real" mitigation strategy is to just not `load` bytecode at all.

But this is probably a non-issue for a lot of usecases.

See e.g.

https://gist.github.com/corsix/6575486

https://www.corsix.org/content/malicious-luajit-bytecode

[girvel]

This is fascinating. I wonder if this issue exists in Lua5.2+, where there is no jit and `load` is able to restrict used environment.

[myrmidon]

Yes, exists. Here is an example for 5.2:

https://ia903205.us.archive.org/15/items/ARMArchitectureRefe...