Thread

Re: COPY FROM ON_ERROR SET_NULL bypasses domain NOT NULL with partial column list

Chao Li <li.evan.chao@gmail.com> — 2026-05-18T22:27:54Z

> On May 18, 2026, at 21:22, Fujii Masao <masao.fujii@gmail.com> wrote:
> 
> On Fri, Apr 17, 2026 at 12:59 PM jian he <jian.universality@gmail.com> wrote:
>> 
>> On Fri, Apr 17, 2026 at 1:09 AM SATYANARAYANA NARLAPURAM
>> <satyanarlapuram@gmail.com> wrote:
>>> 
>>> HI hackers,
>>> 
>>> 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.
>>> 
>>> Fix by allocating with num_phys_attrs and indexing by attnum - 1,
>>> consistent with all other per-column arrays in BeginCopyFrom().
>>> 
>>> Patch is attached, and added a new test case to cover this scenario.
>>> 
>> 
>> The patch looks good to me.
>> I simplified the tests.
> 
> The patch looks good to me. Barring any objections, I will commit it.
> 
> Regards,
> 
> -- 
> 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/