Re: Removing the fixed-size buffer restriction in hba.c

On Mon, Jul 24, 2023 at 03:07:07PM -0300, Fabrízio de Royes Mello wrote:
> On Mon, Jul 24, 2023 at 2:53 PM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>>
>> We got a complaint at [1] about how a not-so-unreasonable LDAP
>> configuration can hit the "authentication file token too long,
>> skipping" error case in hba.c's next_token(). I think we've
>> seen similar complaints before, although a desultory archives
>> search didn't turn one up.
>>
>> A minimum-change response would be to increase the MAX_TOKEN
>> constant from 256 to (say) 1K or 10K. But it wouldn't be all
>> that hard to replace the fixed-size buffer with a StringInfo,
>> as attached.
>>
>
> +1 for replacing it with StringInfo. And the patch LGTM!

I'd suggest noting that next_token() clears buf, but otherwise it looks
reasonable to me, too.

>> Given the infrequency of complaints, I'm inclined to apply
>> the more thorough fix only in HEAD, and to just raise MAX_TOKEN
>> in the back branches. Thoughts?
>>
>
> It makes sense to change it only in HEAD.

I wouldn't be opposed to back-patching the more thorough fix, but I don't
feel too strongly about it.

--
Nathan Bossart
Amazon Web Services: https://aws.amazon.com