[PATCH net-next 2/3] vsock: fix vsock_dequeue/enqueue_accept race
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From: Dexuan Cui <decui@microsoft.com>
Date: 2017-08-15 22:16:01
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Subsystem:
networking [general], the rest, vm sockets (af_vsock) · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Stefano Garzarella
With the current code, when vsock_dequeue_accept() is removing a sock from the list, nothing prevents vsock_enqueue_accept() from adding a new sock into the list concurrently. We should add a lock to protect the list. Signed-off-by: Dexuan Cui <decui@microsoft.com> Cc: Andy King <redacted> Cc: Dmitry Torokhov <redacted> Cc: George Zhang <redacted> Cc: Jorgen Hansen <redacted> Cc: Reilly Grant <redacted> Cc: Asias He <redacted> Cc: Stefan Hajnoczi <stefanha@redhat.com> Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: Cathy Avery <redacted> Cc: K. Y. Srinivasan <redacted> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: Stephen Hemminger <redacted> --- net/vmw_vsock/af_vsock.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index dfc8c51e..b7b2c66 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c@@ -126,6 +126,7 @@ static struct proto vsock_proto = { static const struct vsock_transport *transport; static DEFINE_MUTEX(vsock_register_mutex); +static DEFINE_SPINLOCK(vsock_accept_queue_lock); /**** EXPORTS ****/
@@ -406,7 +407,10 @@ void vsock_enqueue_accept(struct sock *listener, struct sock *connected) sock_hold(connected); sock_hold(listener); + + spin_lock(&vsock_accept_queue_lock); list_add_tail(&vconnected->accept_queue, &vlistener->accept_queue); + spin_unlock(&vsock_accept_queue_lock); } EXPORT_SYMBOL_GPL(vsock_enqueue_accept);
@@ -423,7 +427,10 @@ static struct sock *vsock_dequeue_accept(struct sock *listener) vconnected = list_entry(vlistener->accept_queue.next, struct vsock_sock, accept_queue); + spin_lock(&vsock_accept_queue_lock); list_del_init(&vconnected->accept_queue); + spin_unlock(&vsock_accept_queue_lock); + sock_put(listener); /* The caller will need a reference on the connected socket so we let * it call sock_put().
--
2.7.4