netdev - Re: [PATCH bpf-next v2 3/7] bpf, obj: allow . char as part of the name

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Message-ID: <CAEf4BzYKj6KtAUN8Zisvvp95429cqGgdo4d54LWDtN85_8W3Rw@mail.gmail.com>
Date:   Thu, 28 Feb 2019 21:52:33 -0800
From:   Andrii Nakryiko <andrii.nakryiko@...il.com>
To:     Daniel Borkmann <daniel@...earbox.net>
Cc:     Alexei Starovoitov <ast@...com>, bpf@...r.kernel.org,
        Networking <netdev@...r.kernel.org>, joe@...d.net.nz,
        john.fastabend@...il.com, tgraf@...g.ch,
        Yonghong Song <yhs@...com>, Andrii Nakryiko <andriin@...com>,
        Jakub Kicinski <jakub.kicinski@...ronome.com>,
        lmb@...udflare.com
Subject: Re: [PATCH bpf-next v2 3/7] bpf, obj: allow . char as part of the name

On Thu, Feb 28, 2019 at 3:31 PM Daniel Borkmann <daniel@...earbox.net> wrote:
>
> Trivial addition to allow '.' aside from '_' as "special" characters
> in the object name. Used to name maps from loader side as ".bss",
> ".data", ".rodata".
>
> Signed-off-by: Daniel Borkmann <daniel@...earbox.net>

Acked-by: Andrii Nakryiko <andriin@...com>

> ---
>  kernel/bpf/syscall.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
> index d3ef45e01d7a..90044da3346e 100644
> --- a/kernel/bpf/syscall.c
> +++ b/kernel/bpf/syscall.c
> @@ -440,10 +440,10 @@ static int bpf_obj_name_cpy(char *dst, const char *src)
>         const char *end = src + BPF_OBJ_NAME_LEN;
>
>         memset(dst, 0, BPF_OBJ_NAME_LEN);
> -
> -       /* Copy all isalnum() and '_' char */
> +       /* Copy all isalnum(), '_' and '.' chars. */

Is there any reason names are so restrictive? Say, why not '-' as
well? It's perfectly safe even in filenames. Or even '/' and '\'? Is
this name used by anything else in the system, except for
introspection?

>         while (src < end && *src) {
> -               if (!isalnum(*src) && *src != '_')
> +               if (!isalnum(*src) &&
> +                   *src != '_' && *src != '.')
>                         return -EINVAL;
>                 *dst++ = *src++;
>         }
> --
> 2.17.1
>