Re: [sqlsmith] Infinite recursion in bitshift

On Fri, Oct 14, 2016 at 3:31 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Andreas Seltenreich <seltenreich@gmx.de> writes:
>> Tom Lane writes:
>>> Seems sane, though I wonder if it'd be better to use -INT_MAX rather
>>> than -VARBITMAXLEN.
>
>> I am undecided between those two.  -INT_MAX might be a more precise fix
>> for the problem, but the extra distance to the danger zone was kind of
>> soothing :-).
>
> Yeah, might as well use the tighter limit.
>
> Poking around in varbit.c, I noticed some other places that were assuming
> that a typmod couldn't exceed VARBITMAXLEN.  anybit_typmodin() enforces
> that, but there are places where a user can shove in an arbitrary integer,
> eg
>
> regression=# select "bit"(42, 2147483647);
> ERROR:  invalid memory alloc request size 18446744073441116169
>
> I fixed those too and pushed it.  Thanks for the report!

Curious -- are there real world scenarios where this would happen?

merlin