netdev - Re: [PATCH net] net: lockless sock_i

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CANn89iJOHzk+Sj+3c2PRywQaOMrqpxyodeSbkZ4++5E9xvnTpA@mail.gmail.com>
Date: Mon, 15 Sep 2025 11:51:06 -0700
From: Eric Dumazet <edumazet@...gle.com>
To: Andrei Vagin <avagin@...gle.com>
Cc: "David S . Miller" <davem@...emloft.net>, Jakub Kicinski <kuba@...nel.org>, 
	Paolo Abeni <pabeni@...hat.com>, Simon Horman <horms@...nel.org>, netdev@...r.kernel.org, 
	eric.dumazet@...il.com, syzbot+50603c05bbdf4dfdaffa@...kaller.appspotmail.com, 
	Sebastian Andrzej Siewior <bigeasy@...utronix.de>, Kuniyuki Iwashima <kuniyu@...gle.com>
Subject: Re: [PATCH net] net: lockless sock_i_ino()

On Mon, Sep 15, 2025 at 11:16 AM Andrei Vagin <avagin@...gle.com> wrote:
>
> On Tue, Sep 02, 2025 at 06:36:03PM +0000, Eric Dumazet wrote:
> > @@ -2056,6 +2058,10 @@ static inline int sk_rx_queue_get(const struct sock *sk)
> >  static inline void sk_set_socket(struct sock *sk, struct socket *sock)
> >  {
> >       sk->sk_socket = sock;
> > +     if (sock) {
> > +             WRITE_ONCE(sk->sk_uid, SOCK_INODE(sock)->i_uid);
> > +             WRITE_ONCE(sk->sk_ino, SOCK_INODE(sock)->i_ino);
> > +     }
>
> Hi Eric.
>
> This change breaks CRIU [1]. The issue is that socket_diag reports two
> sockets with the same inode number. It seems inet_csk_clone_lock copies
> sk->sk_ino to child sockets, but sk_set_socket doesn’t reset it to zero
> when sock is NULL.

Hi Andrei, thanks for the report.

Could you test this patch ?

diff --git a/include/net/sock.h b/include/net/sock.h
index 0fd465935334160eeda7c1ea608f5d6161f02cb1..36e11b2afb223bf18ff0596d634e885cca549d0f
100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -2063,6 +2063,9 @@ static inline void sk_set_socket(struct sock
*sk, struct socket *sock)
        if (sock) {
                WRITE_ONCE(sk->sk_uid, SOCK_INODE(sock)->i_uid);
                WRITE_ONCE(sk->sk_ino, SOCK_INODE(sock)->i_ino);
+       } else {
+               /* Note: sk_uid is unchanged. */
+               WRITE_ONCE(sk->sk_ino, 0);
        }
 }

@@ -2084,8 +2087,6 @@ static inline void sock_orphan(struct sock *sk)
        sock_set_flag(sk, SOCK_DEAD);
        sk_set_socket(sk, NULL);
        sk->sk_wq  = NULL;
-       /* Note: sk_uid is unchanged. */
-       WRITE_ONCE(sk->sk_ino, 0);
        write_unlock_bh(&sk->sk_callback_lock);
 }