From fcee53dc03c5aa5bca6631fa0aa900efc3079236 Mon Sep 17 00:00:00 2001 From: Norbert Slusarek Date: Fri, 5 Feb 2021 13:12:06 +0100 Subject: [PATCH] net/vmw_vsock: fix NULL pointer dereference commit 5d1cbcc990f18edaddddef26677073c4e6fad7b7 upstream. In vsock_stream_connect(), a thread will enter schedule_timeout(). While being scheduled out, another thread can enter vsock_stream_connect() as well and set vsk->transport to NULL. In case a signal was sent, the first thread can leave schedule_timeout() and vsock_transport_cancel_pkt() will be called right after. Inside vsock_transport_cancel_pkt(), a null dereference will happen on transport->cancel_pkt. Fixes: c0cfa2d8a788 ("vsock: add multi-transports support") Signed-off-by: Norbert Slusarek Reviewed-by: Stefano Garzarella Link: https://lore.kernel.org/r/trinity-c2d6cede-bfb1-44e2-85af-1fbc7f541715-1612535117028@3c-app-gmx-bap12 Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/vmw_vsock/af_vsock.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c index f64e681493a5..020d87886254 100644 --- a/net/vmw_vsock/af_vsock.c +++ b/net/vmw_vsock/af_vsock.c @@ -1216,7 +1216,7 @@ static int vsock_transport_cancel_pkt(struct vsock_sock *vsk) { const struct vsock_transport *transport = vsk->transport; - if (!transport->cancel_pkt) + if (!transport || !transport->cancel_pkt) return -EOPNOTSUPP; return transport->cancel_pkt(vsk);