[PATCH] net/vmw_vsock: fix NULL pointer dereference

From: Norbert Slusarek <redacted>
Date: Fri, 5 Feb 2021 13:12:06 +0100
Subject: [PATCH] net/vmw_vsock: fix NULL pointer dereference

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")
Reported-by: Norbert Slusarek <redacted>
Signed-off-by: Norbert Slusarek <redacted>
---
 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 6894f21dc147..cb81cfb47a78 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c

@@ -1233,7 +1233,7 @@ 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);
--

2.30.0

On Fri, Feb 05, 2021 at 03:25:17PM +0100, Norbert Slusarek wrote:

I can't see this patch on https://patchwork.kernel.org/project/netdevbpf/list/

Maybe because you forgot to CC the netdev maintainers.
Please next time use scripts/get_maintainer.pl

Anyway the patch LGTM, so

Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>

On Fri, 5 Feb 2021 18:13:35 +0100 Stefano Garzarella wrote:

On Fri, Feb 05, 2021 at 03:25:17PM +0100, Norbert Slusarek wrote:

quoted

From: Norbert Slusarek <redacted>
Date: Fri, 5 Feb 2021 13:12:06 +0100
Subject: [PATCH] net/vmw_vsock: fix NULL pointer dereference

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")
Reported-by: Norbert Slusarek <redacted>
Signed-off-by: Norbert Slusarek <redacted>
---
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 6894f21dc147..cb81cfb47a78 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c

@@ -1233,7 +1233,7 @@ 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);
--
2.30.0
 

I can't see this patch on https://patchwork.kernel.org/project/netdevbpf/list/

Maybe because you forgot to CC the netdev maintainers.
Please next time use scripts/get_maintainer.pl

Anyway the patch LGTM, so

Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>

Applied, thanks!