From: Topi Miettinen <toiwoton@gmail.com>
To: Jan Engelhardt <jengelh@inai.de>
Cc: netfilter-devel@vger.kernel.org
Subject: Re: [PATCH] netfilter: nft_socket: socket expressions for GID & UID
Date: Thu, 21 Apr 2022 19:35:06 +0300 [thread overview]
Message-ID: <42cc8c5d-5874-79a2-61b6-e238c5a1a18f@gmail.com> (raw)
In-Reply-To: <6s7r50n6-r8qs-2295-sq7p-p46qoop97ssn@vanv.qr>
On 21.4.2022 0.15, Jan Engelhardt wrote:
>
> On Wednesday 2022-04-20 20:54, Topi Miettinen wrote:
>
>> Add socket expressions for checking GID or UID of the originating
>> socket. These work also on input side, unlike meta skuid/skgid.
>
> Why exactly is it that meta skuid does not work?
> Because of the skb_to_full_sk() call in nft_meta_get_eval_skugid()?
I don't know the details, but early demux isn't reliable and filters
aren't run after final demux. In my case, something like "ct state new
meta skuid < 1000 drop" as part of input filter doesn't do anything.
Making "meta skuid" 100% reliable would be of course preferable to
adding a new expression.
>
>> + case NFT_SOCKET_GID:
>> + if (sk_fullsock(sk)) {
>> + struct socket *sock;
>> +
>> + sock = sk->sk_socket;
>> + if (sock && sock->file)
>> + *dest = from_kgid_munged(sock_net(sk)->user_ns,
>> + sock->file->f_cred->fsgid);
>
> The code is quite the same as nft_meta_get_eval_skugid's, save for the BH
> locking and skb_to_full_sk. Perhaps nft_socket.c could still call into a
> suitably augmented nft_meta_get_eval_skugid function to share code.
Makes sense.
-Topi
next prev parent reply other threads:[~2022-04-21 16:35 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-20 18:54 [PATCH] netfilter: nft_socket: socket expressions for GID & UID Topi Miettinen
2022-04-20 21:15 ` Jan Engelhardt
2022-04-21 16:35 ` Topi Miettinen [this message]
2022-04-26 21:05 ` Pablo Neira Ayuso
2022-04-26 21:07 ` Pablo Neira Ayuso
2022-04-27 18:07 ` Topi Miettinen
2022-05-02 17:02 ` Pablo Neira Ayuso
2022-04-25 18:45 ` Topi Miettinen
2022-04-25 22:34 ` Florian Westphal
2022-04-26 19:02 ` Topi Miettinen
2022-04-27 5:48 ` Florian Westphal
2022-04-27 7:01 ` Pablo Neira Ayuso
2022-04-27 15:00 ` Topi Miettinen
2022-04-27 15:28 ` Florian Westphal
2022-04-27 15:30 ` Pablo Neira Ayuso
2022-04-27 15:42 ` Florian Westphal
2022-04-27 15:45 ` Pablo Neira Ayuso
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