Patch "vsock/virtio: free queued packets when closing socket" has been added to the 5.10-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    vsock/virtio: free queued packets when closing socket

to the 5.10-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     vsock-virtio-free-queued-packets-when-closing-socket.patch
and it can be found in the queue-5.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 80827d3b2ffe3a9a14cf02843410331a76c474c7
Author: Stefano Garzarella <sgarzare@xxxxxxxxxx>
Date:   Tue Apr 20 13:07:27 2021 +0200

    vsock/virtio: free queued packets when closing socket
    
    [ Upstream commit 8432b8114957235f42e070a16118a7f750de9d39 ]
    
    As reported by syzbot [1], there is a memory leak while closing the
    socket. We partially solved this issue with commit ac03046ece2b
    ("vsock/virtio: free packets during the socket release"), but we
    forgot to drain the RX queue when the socket is definitely closed by
    the scheduled work.
    
    To avoid future issues, let's use the new virtio_transport_remove_sock()
    to drain the RX queue before removing the socket from the af_vsock lists
    calling vsock_remove_sock().
    
    [1] https://syzkaller.appspot.com/bug?extid=24452624fc4c571eedd9
    
    Fixes: ac03046ece2b ("vsock/virtio: free packets during the socket release")
    Reported-and-tested-by: syzbot+24452624fc4c571eedd9@xxxxxxxxxxxxxxxxxxxxxxxxx
    Signed-off-by: Stefano Garzarella <sgarzare@xxxxxxxxxx>
    Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index e4370b1b7494..902cb6dd710b 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -733,6 +733,23 @@ static int virtio_transport_reset_no_sock(const struct virtio_transport *t,
 	return t->send_pkt(reply);
 }
 
+/* This function should be called with sk_lock held and SOCK_DONE set */
+static void virtio_transport_remove_sock(struct vsock_sock *vsk)
+{
+	struct virtio_vsock_sock *vvs = vsk->trans;
+	struct virtio_vsock_pkt *pkt, *tmp;
+
+	/* We don't need to take rx_lock, as the socket is closing and we are
+	 * removing it.
+	 */
+	list_for_each_entry_safe(pkt, tmp, &vvs->rx_queue, list) {
+		list_del(&pkt->list);
+		virtio_transport_free_pkt(pkt);
+	}
+
+	vsock_remove_sock(vsk);
+}
+
 static void virtio_transport_wait_close(struct sock *sk, long timeout)
 {
 	if (timeout) {
@@ -765,7 +782,7 @@ static void virtio_transport_do_close(struct vsock_sock *vsk,
 	    (!cancel_timeout || cancel_delayed_work(&vsk->close_work))) {
 		vsk->close_work_scheduled = false;
 
-		vsock_remove_sock(vsk);
+		virtio_transport_remove_sock(vsk);
 
 		/* Release refcnt obtained when we scheduled the timeout */
 		sock_put(sk);
@@ -828,22 +845,15 @@ static bool virtio_transport_close(struct vsock_sock *vsk)
 
 void virtio_transport_release(struct vsock_sock *vsk)
 {
-	struct virtio_vsock_sock *vvs = vsk->trans;
-	struct virtio_vsock_pkt *pkt, *tmp;
 	struct sock *sk = &vsk->sk;
 	bool remove_sock = true;
 
 	if (sk->sk_type == SOCK_STREAM)
 		remove_sock = virtio_transport_close(vsk);
 
-	list_for_each_entry_safe(pkt, tmp, &vvs->rx_queue, list) {
-		list_del(&pkt->list);
-		virtio_transport_free_pkt(pkt);
-	}
-
 	if (remove_sock) {
 		sock_set_flag(sk, SOCK_DONE);
-		vsock_remove_sock(vsk);
+		virtio_transport_remove_sock(vsk);
 	}
 }
 EXPORT_SYMBOL_GPL(virtio_transport_release);