linux-kernel - Re: [PATCH v2 2/2] fs/sysctl: remove redundant link check in proc_sys_link_fill

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Message-ID: <CAGXu5jLs2Fu+0yUNE4v6+xkfLXdEBs2QY=HctVFGfd__vNPW1g@mail.gmail.com>
Date:   Tue, 27 Feb 2018 15:41:40 -0800
From:   Kees Cook <keescook@...omium.org>
To:     Danilo Krummrich <danilokrummrich@...develop.de>,
        "Luis R. Rodriguez" <mcgrof@...nel.org>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        "linux-fsdevel@...r.kernel.org" <linux-fsdevel@...r.kernel.org>
Subject: Re: [PATCH v2 2/2] fs/sysctl: remove redundant link check in proc_sys_link_fill_cache()

On Tue, Feb 27, 2018 at 3:31 PM, Danilo Krummrich
<danilokrummrich@...develop.de> wrote:
> proc_sys_link_fill_cache() does not need to check whether we're
> called for a link - it's already done by scan().
>
> Signed-off-by: Danilo Krummrich <danilokrummrich@...develop.de>

Acked-by: Kees Cook <keescook@...omium.org>

> ---
> v2: removed 'err' as it's only used for sysctl_follow_link()

Thanks :)

Luis, do you have a tree for sysctl, or should these just go via -mm?

-Kees

> ---
>  fs/proc/proc_sysctl.c | 9 +++------
>  1 file changed, 3 insertions(+), 6 deletions(-)
>
> diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
> index 82ac5f682b73..d36ef667c0a8 100644
> --- a/fs/proc/proc_sysctl.c
> +++ b/fs/proc/proc_sysctl.c
> @@ -712,12 +712,9 @@ static bool proc_sys_link_fill_cache(struct file *file,
>         if (IS_ERR(head))
>                 return false;
>
> -       if (S_ISLNK(table->mode)) {
> -               /* It is not an error if we can not follow the link ignore it */
> -               int err = sysctl_follow_link(&head, &table);
> -               if (err)
> -                       goto out;
> -       }
> +       /* It is not an error if we can not follow the link ignore it */
> +       if (sysctl_follow_link(&head, &table))
> +               goto out;
>
>         ret = proc_sys_fill_cache(file, ctx, head, table);
>  out:
> --
> 2.14.1
>



-- 
Kees Cook
Pixel Security