vsock: fix locking in vsock_shutdown()

commit 1c5fae9c9a092574398a17facc31c533791ef232 upstream.

In vsock_shutdown() we touched some socket fields without holding the
socket lock, such as 'state' and 'sk_flags'.

Also, after the introduction of multi-transport, we are accessing
'vsk->transport' in vsock_send_shutdown() without holding the lock
and this call can be made while the connection is in progress, so
the transport can change in the meantime.

To avoid issues, we hold the socket lock when we enter in
vsock_shutdown() and release it when we leave.

Among the transports that implement the 'shutdown' callback, only
hyperv_transport acquired the lock. Since the caller now holds it,
we no longer take it.

Fixes: d021c344051a ("VSOCK: Introduce VM Sockets")
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index 688717b9a8dba9c1248192e7caa64c2602839eee..eafcc75f289ac06febb6f72f8e40e7a276bfd6cb 100644 (file)
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -823,10 +823,12 @@ static int vsock_shutdown(struct socket *sock, int mode)
         */
 
        sk = sock->sk;
+
+       lock_sock(sk);
        if (sock->state == SS_UNCONNECTED) {
                err = -ENOTCONN;
                if (sk->sk_type == SOCK_STREAM)
-                       return err;
+                       goto out;
        } else {
                sock->state = SS_DISCONNECTING;
                err = 0;
@@ -835,10 +837,8 @@ static int vsock_shutdown(struct socket *sock, int mode)
        /* Receive and send shutdowns are treated alike. */
        mode = mode & (RCV_SHUTDOWN | SEND_SHUTDOWN);
        if (mode) {
-               lock_sock(sk);
                sk->sk_shutdown |= mode;
                sk->sk_state_change(sk);
-               release_sock(sk);
 
                if (sk->sk_type == SOCK_STREAM) {
                        sock_reset_flag(sk, SOCK_DONE);
@@ -846,6 +846,8 @@ static int vsock_shutdown(struct socket *sock, int mode)
                }
        }
 
+out:
+       release_sock(sk);
        return err;
 }
 

diff --git a/net/vmw_vsock/hyperv_transport.c b/net/vmw_vsock/hyperv_transport.c
index 736b76ec8cf012a9c4410529918634cd76f6ed46..ea350a99cfc38b97c1877b7137ee6ab99b75bb4d 100644 (file)
--- a/net/vmw_vsock/hyperv_transport.c
+++ b/net/vmw_vsock/hyperv_transport.c
@@ -444,14 +444,10 @@ static void hvs_shutdown_lock_held(struct hvsock *hvs, int mode)
 
 static int hvs_shutdown(struct vsock_sock *vsk, int mode)
 {
-       struct sock *sk = sk_vsock(vsk);
-
        if (!(mode & SEND_SHUTDOWN))
                return 0;
 
-       lock_sock(sk);
        hvs_shutdown_lock_held(vsk->trans, mode);
-       release_sock(sk);
        return 0;
 }