Re: Using the GNU GMP Library for Bignums in Emacs

[Eli Zaretskii]

> From: Markus Triska <address@hidden>
> Date: Sat, 21 Apr 2018 18:46:07 +0200
> 
> Using GMP has a significant downside if you run out of memory: There’s
> currently no defined way for the allocation functions to recover from an
> error such as out of memory, they must *terminate* program execution.
> 
> Please see the following page for details:
> 
>    https://gmplib.org/manual/Custom-Allocation.html
> 
> Thus, situtations where you can currently throw an Emacs error that can
> be handled in user code would instead terminate the Emacs process. This
> can for example arise from malicious input that involves very large
> integers as results (7^7^7^7 etc.), and of course also elsewhere.
> 
> Also, it may become hard to stop long GMP calculations, whereas you can
> easily stop computations that are written in Elisp. Thus, long GMP
> calculations may lead to denial of editing attacks.

How are those dangers different from using any other external
library.  Like the JSON library, for excample, or libxml2?