From: Tom Lane <tgl@sss.pgh.pa.us>
To: liulang <lang.liu@esgyn.cn>
cc: pgsql-bugs@lists.postgresql.org
Subject: Re: lost status 'STATUS_EOF' for authentication when using 'MD5' or
 'scram-sha-256'
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Comments: In-reply-to liulang <lang.liu@esgyn.cn>
	message dated "Tue, 02 Jan 2024 18:31:00 +0800"
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Date: Tue, 02 Jan 2024 15:28:40 -0500
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liulang <lang.liu@esgyn.cn> writes:
> The above code does not affect the database execution,but 
> ClientAuthentication_hook will be confused whether the password is 
> incorrect or not currently entered?
> so.. The CheckPWChallengeAuth should returns STATUS_EOF when It is, I think.

Yeah, I think you are right.  Overriding the subroutine's result
here is mistaken, even without considering whether it confuses any
ClientAuthentication_hook.  The whole point, as per the comments,
is to not betray to the remote end whether or not there is a user
with a password set.  But if we substitute STATUS_ERROR for
STATUS_EOF then we cause exactly that to happen: if the remote closes
the connection for send only, it can tell by whether an error comes
back whether or not the code found a password.

I think we can do it more simply than you suggest though.  Just
drop the "return STATUS_ERROR" bit; the Assert is enough.

			regards, tom lane