linux-kernel - Re: [PATCH 12/46] selinux: Move assignments for two pointers in genfs

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Date:   Thu, 23 Mar 2017 17:48:54 -0400
From:   Paul Moore <paul@...l-moore.com>
To:     SF Markus Elfring <elfring@...rs.sourceforge.net>
Cc:     linux-security-module@...r.kernel.org, selinux@...ho.nsa.gov,
        Eric Paris <eparis@...isplace.org>,
        James Morris <james.l.morris@...cle.com>,
        "Serge E. Hallyn" <serge@...lyn.com>,
        Stephen Smalley <sds@...ho.nsa.gov>,
        William Roberts <william.c.roberts@...el.com>,
        LKML <linux-kernel@...r.kernel.org>,
        kernel-janitors@...r.kernel.org
Subject: Re: [PATCH 12/46] selinux: Move assignments for two pointers in genfs_read()

On Sun, Jan 15, 2017 at 10:12 AM, SF Markus Elfring
<elfring@...rs.sourceforge.net> wrote:
> From: Markus Elfring <elfring@...rs.sourceforge.net>
> Date: Sat, 14 Jan 2017 16:56:51 +0100
>
> Move the assignment for the local variables "newc" and "newgenfs" behind
> a call of the function "next_entry" at the beginning so that they will
> only be set after a successful call.
>
> Signed-off-by: Markus Elfring <elfring@...rs.sourceforge.net>
> ---
>  security/selinux/ss/policydb.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)

I think it is cleaner, and arguably safer, the way it is now.  I'm not
worried about performance gains in the error path, especially when
those gains are probably not measurable.

> diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c
> index 754f829d2027..7544e374dec9 100644
> --- a/security/selinux/ss/policydb.c
> +++ b/security/selinux/ss/policydb.c
> @@ -1997,14 +1997,14 @@ static int genfs_read(struct policydb *p, void *fp)
>         int i, j, rc;
>         u32 nel, nel2, len, len2;
>         __le32 buf[1];
> -       struct ocontext *l, *c;
> -       struct ocontext *newc = NULL;
> -       struct genfs *genfs_p, *genfs;
> -       struct genfs *newgenfs = NULL;
> +       struct ocontext *l, *c, *newc;
> +       struct genfs *genfs_p, *genfs, *newgenfs;
>
>         rc = next_entry(buf, fp, sizeof(u32));
>         if (rc)
>                 return rc;
> +       newc = NULL;
> +       newgenfs = NULL;
>         nel = le32_to_cpu(buf[0]);
>
>         for (i = 0; i < nel; i++) {
> --
> 2.11.0
>



-- 
paul moore
www.paul-moore.com