Date: Mon, 6 Jan 2020 14:18:00 +0900
From: Michael Paquier <michael@paquier.xyz>
To: starbugs@qq.com, pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #16190: The usage of NULL pointer in refint.c
Message-ID: <20200106051800.GL3598@paquier.xyz>
References: <16190-70181c803641c3dc@postgresql.org>
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On Mon, Jan 06, 2020 at 03:39:36AM +0000, PG Bug reporting form wrote:
> We checked the code in file =E2=80=9Crefint.c=E2=80=9D and there is one e=
rror occurring in
> line 636. This error is caused by the usage of pointer with NULL value. T=
he
> code in this line is =E2=80=9Cnewp->ident =3D strdup(ident);=E2=80=9D The=
 pointer =E2=80=9Cnewp=E2=80=9D is
> defined by the code in line 615 as =E2=80=9CEPlan *newp;=E2=80=9D and ini=
tialized by the
> code in line 628 as =E2=80=9Cnewp =3D *eplan + i;=E2=80=9D or in line 632=
 as =E2=80=9Cnewp =3D *eplan =3D
> (EPlan *) malloc(sizeof(EPlan));=E2=80=9D according to different conditio=
ns. In the
> first condition, the =E2=80=9C*eplan=E2=80=9D is valued by the code =E2=
=80=9C*eplan =3D (EPlan *)
> realloc(*eplan, (i + 1) * sizeof(EPlan));=E2=80=9D in line 627. We found =
the code
> hasn=E2=80=99t checked if the process =E2=80=9Crealloc=E2=80=9D and =E2=
=80=9Cmalloc=E2=80=9D are success or not
> which directly define the value of =E2=80=9C*eplan=E2=80=9D. The program =
should check the
> effectiveness of the return value of function =E2=80=9Crealloc=E2=80=9D a=
nd =E2=80=9Cmalloc=E2=80=9D to
> avoid this error.

It could be better to switch all that to not use directly system
calls, and rely properly on a high-level memory context with
palloc-like allocations.  There could be also an argument to just
remove the module per the lack of attention it is getting, though it
is still useful as an example of use for SPI, and the docs mention
it for that.
--
Michael

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