From: Michal Kubecek <mkubecek@suse.cz>
To: Johannes Berg <johannes@sipsolutions.net>
Cc: linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
Johannes Berg <johannes.berg@intel.com>
Subject: Re: [RFC] netlink: add NLA_REJECT policy type
Date: Wed, 12 Sep 2018 10:16:22 +0200 [thread overview]
Message-ID: <20180912081621.GC29691@unicorn.suse.cz> (raw)
In-Reply-To: <20180912073245.8047-1-johannes@sipsolutions.net>
On Wed, Sep 12, 2018 at 09:32:45AM +0200, Johannes Berg wrote:
> From: Johannes Berg <johannes.berg@intel.com>
>
> In some situations some netlink attributes may be used for output
> only (kernel->userspace) or may be reserved for future use. It's
> then helpful to be able to prevent userspace from using them in
> messages sent to the kernel, since they'd otherwise be ignored and
> any future will become impossible if this happens.
>
> Add NLA_REJECT to the policy which does nothing but reject (with
> EINVAL) validation of any messages containing this attribute.
>
> The specific case I have in mind now is a shared nested attribute
> containing request/response data, and it would be pointless and
> potentially confusing to have userspace include response data in
> the messages that actually contain a request.
I find this feature very useful. Actually, I was a bit surprised when
I found I can't mark an attribute "forbidden" using policy.
IMHO it would be even nicer if one could also specify an error message
to use in extack if NLA_REJECT is applied; the easiest way would be
using .validation_data and passing extack to validate_nla() but I'm not
sure if it wouldn't qualify as an abuse.
Michal Kubecek
next prev parent reply other threads:[~2018-09-12 13:19 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-12 7:32 [RFC] netlink: add NLA_REJECT policy type Johannes Berg
2018-09-12 8:16 ` Michal Kubecek [this message]
2018-09-12 8:21 ` Johannes Berg
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180912081621.GC29691@unicorn.suse.cz \
--to=mkubecek@suse.cz \
--cc=johannes.berg@intel.com \
--cc=johannes@sipsolutions.net \
--cc=linux-wireless@vger.kernel.org \
--cc=netdev@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).