[PATCH 4.4 02/20] vsock: cope with memory allocation failure at socket creation time

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

[ Upstream commit 225d9464268599a5b4d094d02ec17808e44c7553 ]

In the unlikely event that the kmalloc call in vmci_transport_socket_init()
fails, we end-up calling vmci_transport_destruct() with a NULL vmci_trans()
and oopsing.

This change addresses the above explicitly checking for zero vmci_trans()
at destruction time.

Reported-by: Xiumei Mu <xmu@xxxxxxxxxx>
Fixes: d021c344051a ("VSOCK: Introduce VM Sockets")
Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Reviewed-by: Stefano Garzarella <sgarzare@xxxxxxxxxx>
Reviewed-by: Jorgen Hansen <jhansen@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 net/vmw_vsock/vmci_transport.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/net/vmw_vsock/vmci_transport.c b/net/vmw_vsock/vmci_transport.c
index d24773552b641..217810674c358 100644
--- a/net/vmw_vsock/vmci_transport.c
+++ b/net/vmw_vsock/vmci_transport.c
@@ -1656,6 +1656,10 @@ static void vmci_transport_cleanup(struct work_struct *work)
 
 static void vmci_transport_destruct(struct vsock_sock *vsk)
 {
+	/* transport can be NULL if we hit a failure at init() time */
+	if (!vmci_trans(vsk))
+		return;
+
 	/* Ensure that the detach callback doesn't use the sk/vsk
 	 * we are about to destruct.
 	 */
-- 
2.19.1