From: Tom Lane <tgl@sss.pgh.pa.us>
To: tharakan@gmail.com
cc: pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #17022: SQL causing engine crash
In-reply-to: <17022-8e7e280c9b4baedb@postgresql.org>
References: <17022-8e7e280c9b4baedb@postgresql.org>
Comments: In-reply-to PG Bug reporting form <noreply@postgresql.org>
	message dated "Wed, 19 May 2021 06:58:19 -0000"
MIME-Version: 1.0
Content-Type: text/plain; charset="UTF-8"
Content-ID: <3430324.1621435835.1@sss.pgh.pa.us>
Content-Transfer-Encoding: quoted-printable
Date: Wed, 19 May 2021 10:50:35 -0400
Message-ID: <3430325.1621435835@sss.pgh.pa.us>
Archived-At: 
 <https://www.postgresql.org/message-id/3430325.1621435835%40sss.pgh.pa.us>
Precedence: bulk

PG Bug reporting form <noreply@postgresql.org> writes:
> SQLSmith is constantly crashing v13.3 with SQL(s) that appear linked to =
a
> PostGIS (v3.0.3) bug - see Error Report below.

Yeah, I agree, it's a postgis bug.

> I decided to post this here (backtracking on an earlier thought), since =
#0 /
> #1 are=C2=A0postgres functions and I wasn't really sure if the arguments=
 to these
> functions are sanitized. For e.g. whether pg_detoast_datum_slice() is
> expected to check input bounds (count=3D40 in this case).

The trace shows that gserialized_datum_get_gidx_p is passing a NULL
datum pointer to pg_detoast_datum_slice.  Whether the slice length
is appropriate seems like an academic question.

(It does look like that code validates sliceoffset and slicelength
and does something appropriate if they're outside the bounds of
the datum's size.  But you gotta have a datum.)

			regards, tom lane