From: Daniel Borkmann <daniel@iogearbox•net>
To: Eric Dumazet <eric.dumazet@gmail•com>,
Lorenzo Colitti <lorenzo@google•com>
Cc: Chenbo Feng <chenbofeng.kernel@gmail•com>,
"David S . Miller" <davem@davemloft•net>,
Alexei Starovoitov <ast@fb•com>,
"netdev@vger•kernel.org" <netdev@vger•kernel.org>,
Willem de Bruijn <willemb@google•com>,
Chenbo Feng <fengc@google•com>
Subject: Re: [PATCH net-next 2/2] Add a eBPF helper function to retrieve socket uid
Date: Fri, 03 Feb 2017 09:25:37 +0100 [thread overview]
Message-ID: <58943E81.4030802@iogearbox.net> (raw)
In-Reply-To: <1486086708.21871.48.camel@edumazet-glaptop3.roam.corp.google.com>
On 02/03/2017 02:51 AM, Eric Dumazet wrote:
> On Fri, 2017-02-03 at 10:18 +0900, Lorenzo Colitti wrote:
>> On Fri, Feb 3, 2017 at 9:31 AM, Eric Dumazet <eric.dumazet@gmail•com> wrote:
>>>> It should be safe to call sock_net_uid on any type of socket
>>>> (including NULL). sk_uid was added to struct sock in 86741ec25462
>>>> ("net: core: Add a UID field to struct sock.")
>>>
>>> But a request socket or a timewait socket do not have this field.
>>>
>>> Daniel point is valid.
>>
>> My bad. Yes.
>>
>> It would definitely be useful to have the UID available in request
>> sockets, and perhaps timewait sockets as well. That could be done by
>> moving the UID to sock_common, or with something along the lines of:
>>
>> static inline kuid_t sock_net_uid(const struct net *net, const struct sock *sk)
>> {
>> + if (sk && sk->sk_state == TCP_NEW_SYN_RECV)
>> + sk = sk->__sk_common.skc_listener;
>> + else if (sk && !sk_fullsock(sk))
>> + sk = NULL;
>> +
>> return sk ? sk->sk_uid : make_kuid(net->user_ns, 0);
>> }
>>
>> Any thoughts on which is better?
>
> You could use
>
> if (sk) {
> sk = sk_to_full_sk(sk);
> if (sk_fullsock(sk))
> return sk->sk_uid;
> }
Yeah, if that moves into the sock_net_uid() helper, then you could
remove the sk && sk_fullsock(sk) ? sk : NULL tests from the current
sock_net_uid() call sites such as in tcp code. Maybe then also make
the sock_net_uid() as __always_inline, so that most of the callers
with sock_net_uid(net, NULL) are guaranteed to optimize away their
sk checks at compile time?
next prev parent reply other threads:[~2017-02-03 8:25 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-02 20:59 [PATCH net-next 0/2] net: core: Two Helper function about socket information Chenbo Feng
2017-02-02 20:59 ` [PATCH net-next 1/2] Add a helper function to get socket cookie in eBPF Chenbo Feng
2017-02-02 21:23 ` Daniel Borkmann
2017-02-02 20:59 ` [PATCH net-next 2/2] Add a eBPF helper function to retrieve socket uid Chenbo Feng
2017-02-02 21:32 ` Daniel Borkmann
2017-02-03 0:00 ` Lorenzo Colitti
2017-02-03 0:28 ` Daniel Borkmann
2017-02-03 0:31 ` Eric Dumazet
2017-02-03 1:18 ` Lorenzo Colitti
2017-02-03 1:51 ` Eric Dumazet
2017-02-03 8:25 ` Daniel Borkmann [this message]
2017-02-06 3:25 ` Lorenzo Colitti
2017-02-03 0:13 ` [PATCH net-next 0/2] net: core: Two Helper function about socket information Alexei Starovoitov
2017-02-03 16:19 ` Lorenzo Colitti
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