Re: BUG #19601: Vuln45: Unbounded recursion via self-retying Perl scalar in bool_plperl's SvTRUE call causes backend

Andrey Rachitskiy <pl0h0yp1(at)gmail(dot)com> writes:
> Thanks for the report. I can reproduce the SIGSEGV on current master
> (with --with-perl).

I can't get excited about this. A plperl user who wishes to cause
recursion to stack overflow can do so far more simply than what is
proposed here: just write an indefinitely-recursive Perl function
and call it. That recursion will be totally inside libperl, so
we can do nothing about it. The same holds for every other PL
that exposes a general-purpose programming language.

I certainly wouldn't add the amount of code you propose here to close
off just one route to that, even if I trusted the patch which I don't.
(It seems far too much in-bed with details of libperl's innards, and
hence likely to fail on other Perl versions than what you tested.)

regards, tom lane