From ac79b1d94a88cb52cfd7624d5f32c833cf2f9f4d Mon Sep 17 00:00:00 2001 From: Stefano Garzarella Date: Tue, 9 Feb 2021 09:52:19 +0100 Subject: [PATCH] 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 Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/vmw_vsock/af_vsock.c | 8 +++++--- net/vmw_vsock/hyperv_transport.c | 4 ---- 2 files changed, 5 insertions(+), 7 deletions(-) diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c index 89a57ed99abb..5d323574d04f 100644 --- a/net/vmw_vsock/af_vsock.c +++ b/net/vmw_vsock/af_vsock.c @@ -808,10 +808,12 @@ 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; @@ -820,10 +822,8 @@ 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); @@ -831,6 +831,8 @@ 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 463cefc1e5ae..a3c57c048cbd 100644 --- a/net/vmw_vsock/hyperv_transport.c +++ b/net/vmw_vsock/hyperv_transport.c @@ -464,14 +464,10 @@ 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; }