Re: lower() and unaccent() not leakproof

> On 26 Aug 2021, at 09:58, Peter Eisentraut <peter(dot)eisentraut(at)enterprisedb(dot)com> wrote:
>
> On 26.08.21 06:52, David G. Johnston wrote:
>> On Wednesday, August 25, 2021, Christophe Pettus <xof(at)thebuild(dot)com <mailto:xof(at)thebuild(dot)com>> wrote:
>> lower() and unaccent() (and most string functions) are not marked as
>> leakproof. Is this due to possible locale / character encoding
>> errors they might encounter?
>> I think you are partially correct. Its due to the fact that error messages, regardless of the root cause, result in the printing of the input value in the error message as context, thus exists a leak via a violation of “ It reveals no information about its arguments other than by its return value. ”
>
> I think if you trace the code, you might find that lower() and upper() can't really leak anything. It might be worth taking a careful look and possibly lifting this restriction.

Wouldn’t the difference in possible error messages in upper/lower be able to
leak whether the input is ascii or wide chars, and/or the collation?

--
Daniel Gustafsson https://vmware.com/