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From:   Austin Kim <austindh.kim@gmail.com>
Date:   Thu, 15 Jul 2021 06:44:52 +0900
Message-ID: <CADLLry6RmSDuB4nmVKDEiqxXmEU0xrhMn2wieuuVTypMWqc4cQ@mail.gmail.com>
Subject: Re: [PATCH] LSM: add NULL check for kcalloc()
To:     James Morris <jmorris@namei.org>
Cc:     "Serge E. Hallyn" <serge@hallyn.com>,
        Kees Cook <keescook@chromium.org>,
        linux-security-module <linux-security-module@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        =?UTF-8?B?6rmA64+Z7ZiE?= <austin.kim@lge.com>,
        kernel-team@lge.com
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2021=EB=85=84 7=EC=9B=94 15=EC=9D=BC (=EB=AA=A9) =EC=98=A4=EC=A0=84 4:12, J=
ames Morris <jmorris@namei.org>=EB=8B=98=EC=9D=B4 =EC=9E=91=EC=84=B1:
>
> On Tue, 13 Jul 2021, Austin Kim wrote:
>
> > From: Austin Kim <austin.kim@lge.com>
> >
> > kcalloc() may return NULL when memory allocation fails.
> > So it is necessary to add NULL check after the call to kcalloc() is mad=
e.
> >
> > Signed-off-by: Austin Kim <austin.kim@lge.com>
> > ---
> >  security/security.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/security/security.c b/security/security.c
> > index 09533cbb7221..f885c9e9bc35 100644
> > --- a/security/security.c
> > +++ b/security/security.c
> > @@ -321,6 +321,8 @@ static void __init ordered_lsm_init(void)
> >
> >       ordered_lsms =3D kcalloc(LSM_COUNT + 1, sizeof(*ordered_lsms),
> >                               GFP_KERNEL);
> > +     if (ordered_lsms)
> > +             return;
>
> Your logic is reversed here.

I feel very sorry for my terrible mistake.
'if (ordered_lsms)' should have been 'if (!ordered_lsms)'.

Let me resend patch(v2) soon.

Thanks,
Austin Kim

>
> Should this also be a kernel panic?
>
> >
> >       if (chosen_lsm_order) {
> >               if (chosen_major_lsm) {
> > --
> > 2.20.1
> >
>
> --
> James Morris
> <jmorris@namei.org>
>