diff mbox series

[4.19,33/50] vsock: fix locking in vsock_shutdown()

Message ID 20210222121026.072410085@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

Greg Kroah-Hartman Feb. 22, 2021, 12:13 p.m. UTC 
From: Stefano Garzarella <sgarzare@redhat.com>

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>
---
 net/vmw_vsock/af_vsock.c         |    8 +++++---
 net/vmw_vsock/hyperv_transport.c |    4 ----
 2 files changed, 5 insertions(+), 7 deletions(-)
diff mbox series

Patch

--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -816,10 +816,12 @@  static int vsock_shutdown(struct socket
 	 */
 
 	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;
@@ -828,10 +830,8 @@  static int vsock_shutdown(struct socket
 	/* 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);
@@ -839,6 +839,8 @@  static int vsock_shutdown(struct socket
 		}
 	}
 
+out:
+	release_sock(sk);
 	return err;
 }
 
--- a/net/vmw_vsock/hyperv_transport.c
+++ b/net/vmw_vsock/hyperv_transport.c
@@ -443,14 +443,10 @@  static void hvs_shutdown_lock_held(struc
 
 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;
 }