Subject: Re: Remove line length restriction in passwordFromFile()
From: Fujii Masao <masao.fujii@oss.nttdata.com>
To: Tom Lane <tgl@sss.pgh.pa.us>, pgsql-hackers@lists.postgresql.org
Cc: Fujii Masao <fujii@postgresql.org>
References: <4187382.1598909041@sss.pgh.pa.us>
 <90aed8c6-a171-4cf7-4e4a-0d4d9593f6c5@oss.nttdata.com>
Message-ID: <b2391bb7-33c5-a25e-e99a-81f7e96efdad@oss.nttdata.com>
Date: Tue, 1 Sep 2020 14:41:09 +0900
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On 2020/09/01 10:00, Fujii Masao wrote:
> 
> 
> On 2020/09/01 6:24, Tom Lane wrote:
>> Per the discussion at [1], we're now aware of actual use-cases for
>> password strings approaching a kilobyte in length.  I think this puts
>> the final nail in the coffin of the idea that passwordFromFile() can
>> use a fixed-length line buffer.  Therefore, commit 2eb3bc588 (which
>> added a warning for overlength lines) seems rather misguided in
>> hindsight.  What we should do instead is fix that code so it has no
>> hard upper bound on the line length.
> 
> AFAIR, there were proposals to increase the maximum length of password so far,
> but we could not do that because we failed to get the consensus about
> that change. But if we get the clear use-case requiring longer password and
> reach the consensus, that's good news. I agree with the change.
> 
>> Even if you want to say that
>> we'll set a particular limit on how long the password field can be,
>> there's no good upper bound for the length of the hostname field;
>> so ISTM that just getting out of the business of a fixed-size buffer
>> is the sanest way.
>>
>> Hence, the attached proposed patch does that, and for good measure
>> adds some testing of this formerly untested code.

The patch looks good to me, except the following minor thing.

+		if (fgets(buf.data + buf.len, buf.maxlen - buf.len - 1, fp) == NULL)

IIUC fgets() reads the data with the specified size - 1, so ISTM that -1 of
"buf.maxlen - buf.len - 1" is not necessary.

Regards,

-- 
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION