linux-kernel - Re: [PATCH v2 net-next 1/2] net: bpf: handle return value of BPF_CGROUP_RUN_PROG_INET{4,6}_POST

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Message-ID: <CADxym3aBqBPAMT59dbDoAHvVyXq9ZQBc99Z+kje40UmzHUp+QQ@mail.gmail.com>
Date:   Wed, 5 Jan 2022 21:03:13 +0800
From:   Menglong Dong <menglong8.dong@...il.com>
To:     Daniel Borkmann <daniel@...earbox.net>
Cc:     Jakub Kicinski <kuba@...nel.org>,
        David Miller <davem@...emloft.net>,
        Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>,
        David Ahern <dsahern@...nel.org>,
        Eric Dumazet <edumazet@...gle.com>,
        Alexei Starovoitov <ast@...nel.org>,
        Andrii Nakryiko <andrii@...nel.org>, Martin Lau <kafai@...com>,
        Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
        John Fastabend <john.fastabend@...il.com>,
        KP Singh <kpsingh@...nel.org>, netdev <netdev@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>, bpf <bpf@...r.kernel.org>,
        Menglong Dong <imagedong@...cent.com>
Subject: Re: [PATCH v2 net-next 1/2] net: bpf: handle return value of BPF_CGROUP_RUN_PROG_INET{4,6}_POST_BIND()

On Wed, Jan 5, 2022 at 9:01 PM Daniel Borkmann <daniel@...earbox.net> wrote:
>
> On 12/30/21 9:03 AM, menglong8.dong@...il.com wrote:
> [...]
> > diff --git a/include/net/sock.h b/include/net/sock.h
> > index 44cc25f0bae7..f5fc0432374e 100644
> > --- a/include/net/sock.h
> > +++ b/include/net/sock.h
> > @@ -1209,6 +1209,7 @@ struct proto {
> >       void                    (*unhash)(struct sock *sk);
> >       void                    (*rehash)(struct sock *sk);
> >       int                     (*get_port)(struct sock *sk, unsigned short snum);
> > +     void                    (*put_port)(struct sock *sk);
> >   #ifdef CONFIG_BPF_SYSCALL
> >       int                     (*psock_update_sk_prot)(struct sock *sk,
> >                                                       struct sk_psock *psock,
> > diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
> > index 5d18d32557d2..8784e72d4b8b 100644
> > --- a/net/ipv4/af_inet.c
> > +++ b/net/ipv4/af_inet.c
> > @@ -531,6 +531,8 @@ int __inet_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len,
> >                       err = BPF_CGROUP_RUN_PROG_INET4_POST_BIND(sk);
> >                       if (err) {
> >                               inet->inet_saddr = inet->inet_rcv_saddr = 0;
> > +                             if (sk->sk_prot->get_port)
> > +                                     sk->sk_prot->put_port(sk);
> >                               goto out_release_sock;
> >                       }
> >               }
> [...]
> > diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
> > index d1636425654e..ddfc6821e682 100644
> > --- a/net/ipv6/af_inet6.c
> > +++ b/net/ipv6/af_inet6.c
> > @@ -413,6 +413,8 @@ static int __inet6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len,
> >                       if (err) {
> >                               sk->sk_ipv6only = saved_ipv6only;
> >                               inet_reset_saddr(sk);
> > +                             if (sk->sk_prot->get_port)
> > +                                     sk->sk_prot->put_port(sk);
> >                               goto out;
> >                       }
> >               }
>
> I presume both tests above should test for non-zero sk->sk_prot->put_port
> callback given that is what they end up calling when true, no?
>

You are right, I think that I made a big mistake here...:/

Thanks!
Menglong Dong