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Subject: Re: COPY FROM ON_ERROR SET_NULL bypasses domain NOT NULL with partial
 column list
From: Chao Li <li.evan.chao@gmail.com>
In-Reply-To: 
 <CAHGQGwEvUj+ycr5vYMPQhZ8gk1of4HiSGfKVBJ15nA8d3MyDhQ@mail.gmail.com>
Date: Tue, 19 May 2026 06:27:54 +0800
Cc: jian he <jian.universality@gmail.com>,
 SATYANARAYANA NARLAPURAM <satyanarlapuram@gmail.com>,
 PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
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To: Fujii Masao <masao.fujii@gmail.com>
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 <https://www.postgresql.org/message-id/0ED082D4-70CB-4144-8A00-EFE63FCC15B1%40gmail.com>
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> On May 18, 2026, at 21:22, Fujii Masao <masao.fujii@gmail.com> wrote:
>=20
> On Fri, Apr 17, 2026 at 12:59=E2=80=AFPM jian he =
<jian.universality@gmail.com> wrote:
>>=20
>> On Fri, Apr 17, 2026 at 1:09=E2=80=AFAM SATYANARAYANA NARLAPURAM
>> <satyanarlapuram@gmail.com> wrote:
>>>=20
>>> HI hackers,
>>>=20
>>> domain_with_constraint[] was allocated with list_length(attnumlist)
>>> elements and indexed sequentially via foreach_current_index(), but
>>> copyfromparse.c accesses it via attnum - 1 (physical attribute =
index).
>>> With a partial column list targeting high-numbered columns, this =
caused
>>> an out-of-bounds read that bypassed domain NOT NULL checks, silently
>>> inserting NULL into NOT NULL domain columns.
>>>=20
>>> Fix by allocating with num_phys_attrs and indexing by attnum - 1,
>>> consistent with all other per-column arrays in BeginCopyFrom().
>>>=20
>>> Patch is attached, and added a new test case to cover this scenario.
>>>=20
>>=20
>> The patch looks good to me.
>> I simplified the tests.
>=20
> The patch looks good to me. Barring any objections, I will commit it.
>=20
> Regards,
>=20
> --=20
> Fujii Masao

I also found this bug and reported it here [1]. I just reviewed v2, the =
code change of the fix itself is exactly the same as my version in [1]. =
The new test is slightly different from my version, but I think that =
also works.

[1] =
https://www.postgresql.org/message-id/8A72720A-55AC-4D41-B9DF-5610307600E6=
%40gmail.com

Best regards,
--
Chao Li (Evan)
HighGo Software Co., Ltd.
https://www.highgo.com/