net: add sock_init_data_uid()

Add sock_init_data_uid() to explicitly initialize the socket uid.
To initialise the socket uid, sock_init_data() assumes a the struct
socket* sock is always embedded in a struct socket_alloc, used to
access the corresponding inode uid. This may not be true.
Examples are sockets created in tun_chr_open() and tap_open().

Fixes: 86741ec25462 ("net: core: Add a UID field to struct sock.")
Signed-off-by: Pietro Borrello <borrello@diag.uniroma1.it>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/sock.h b/include/net/sock.h
index dcd72e6..937e842 100644 (file)
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1956,7 +1956,12 @@ void sk_common_release(struct sock *sk);
  *     Default socket callbacks and setup code
  */
 
-/* Initialise core socket variables */
+/* Initialise core socket variables using an explicit uid. */
+void sock_init_data_uid(struct socket *sock, struct sock *sk, kuid_t uid);
+
+/* Initialise core socket variables.
+ * Assumes struct socket *sock is embedded in a struct socket_alloc.
+ */
 void sock_init_data(struct socket *sock, struct sock *sk);
 
 /*

diff --git a/net/core/sock.c b/net/core/sock.c
index f08b76a..208634b 100644 (file)
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -3383,7 +3383,7 @@ void sk_stop_timer_sync(struct sock *sk, struct timer_list *timer)
 }
 EXPORT_SYMBOL(sk_stop_timer_sync);
 
-void sock_init_data(struct socket *sock, struct sock *sk)
+void sock_init_data_uid(struct socket *sock, struct sock *sk, kuid_t uid)
 {
        sk_init_common(sk);
        sk->sk_send_head        =       NULL;
@@ -3403,11 +3403,10 @@ void sock_init_data(struct socket *sock, struct sock *sk)
                sk->sk_type     =       sock->type;
                RCU_INIT_POINTER(sk->sk_wq, &sock->wq);
                sock->sk        =       sk;
-               sk->sk_uid      =       SOCK_INODE(sock)->i_uid;
        } else {
                RCU_INIT_POINTER(sk->sk_wq, NULL);
-               sk->sk_uid      =       make_kuid(sock_net(sk)->user_ns, 0);
        }
+       sk->sk_uid      =       uid;
 
        rwlock_init(&sk->sk_callback_lock);
        if (sk->sk_kern_sock)
@@ -3466,6 +3465,16 @@ void sock_init_data(struct socket *sock, struct sock *sk)
        refcount_set(&sk->sk_refcnt, 1);
        atomic_set(&sk->sk_drops, 0);
 }
+EXPORT_SYMBOL(sock_init_data_uid);
+
+void sock_init_data(struct socket *sock, struct sock *sk)
+{
+       kuid_t uid = sock ?
+               SOCK_INODE(sock)->i_uid :
+               make_kuid(sock_net(sk)->user_ns, 0);
+
+       sock_init_data_uid(sock, sk, uid);
+}
 EXPORT_SYMBOL(sock_init_data);
 
 void lock_sock_nested(struct sock *sk, int subclass)