Re: [PATCH] LSM: add NULL check for kcalloc()

[Ken Goldman]

On 7/14/2021 5:44 PM, Austin Kim wrote:
> 2021년 7월 15일 (목) 오전 4:12, James Morris <jmorris@xxxxxxxxx>님이 작성:
> > On Tue, 13 Jul 2021, Austin Kim wrote:
> >
> > > From: Austin Kim <austin.kim@xxxxxxx>
> > >
> > > kcalloc() may return NULL when memory allocation fails.
> > > So it is necessary to add NULL check after the call to kcalloc() is made.
> > >
> > > Signed-off-by: Austin Kim <austin.kim@xxxxxxx>
> > > ---
> > >   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 = 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)'.

I know it's a bit more typing, but

	if (ordered_lsms == NULL)

compiles down to the same binary and avoids there errors that
try to treat a pointer as a boolean.

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