Lua globals protection - Githubissues

monome / crow

Crow speaks and listens and remembers bits of text. A scriptable USB-CV-II machine

GNU General Public License v3.0

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Lua globals protection #11

Closed trentgill closed 4 years ago

trentgill commented 5 years ago

Need a solution to make sure the user can't create a script (saved in flash as the default) that makes the lua environment unresponsive, thus being unable to change the script.

Ideas:

make certain functions in a protected table
make a copy of said functions and test for equality to the runtime versions.

These would include a small number of functions that would break script-updating (dostring(), usb2repl() etc).

pq commented 5 years ago

fwiw, there's a bunch of conversation on the norns repo that might be relevant here.

the globals meta-issue is a good place to start (if you haven't perused it already): https://github.com/monome/norns/issues/557.

i'd be curious if the "readonly table" hack in https://github.com/monome/norns/pull/667 might be useful?

tehn commented 5 years ago

the readonly function is a good solution for this. it'd be trivial to add.

i'll get it into the core lib.

trentgill commented 5 years ago

readonly approach seems good to me.

What are we thinking to protect? My first thoughts:

Everything in bootstrap.lua. Can readonly be applied to a global function (ie print)?
_c
Input, Output, Asl, Asllib, Cal
All the C-functions (do these need to be put into a table of their own?)

Metro/metro & II are different though as they have a lot of internal functionality that shouldn't changed, but they can be modified to setup event callbacks, so can't be totally protected. I'm guessing Midi will be in this same category but we'll cross that bridge at the appropriate time.

trentgill commented 5 years ago

Demoting to 1.1 as this feels like a problem we can solve when it arises?

pq commented 5 years ago

sorry for the slow reply; i haven't dug deeply into the APIs yet but my gut says your candidates look right. the C-functions should get guarded somehow for sure. i think we can follow the lead of whatever we end up doing for norns...

anyway, agreed we can tackle all of this opportunistically!

trentgill commented 4 years ago

A non issue in practice.