Re: @(#)Mordred Labs advisory 0x0003: Buffer overflow in PostgreSQL (fwd)

Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> writes:

> Vince Vielhaber <vev(at)michvhf(dot)com> writes:
> > Here's yet another. He claims malicious code can be run on the server
> > with this one.
>
> regression=# select repeat('xxx',1431655765);
> server closed the connection unexpectedly
>
> This is probably caused by integer overflow in calculating the size of
> the repeat's result buffer. It'd take some considerable doing to create
> an arbitrary-code exploit, but perhaps could be done. Anyone want to
> investigate a patch?

This seems to fix the problem:

nconway=# select repeat('xxx',1431655765);
ERROR: Requested buffer is too large.

It uses the logic you suggested. Just a quick and dirty fix, I may
have missed something... The patch applies cleanly to both CVS HEAD
and the 7.2 stable branch.

Cheers,

Neil

--
Neil Conway <neilc(at)samurai(dot)com> || PGP Key ID: DB3C29FC