[PATCH v1] VSOCK: fix Information Leak in virtio_transport_shutdown()

[bsdhenrymartin@gmail.com]

From: Henry Martin <bsdhenryma@tencent.com>

The `struct virtio_vsock_pkt_info` is declared on the stack but only
partially initialized (only `op`, `flags`, and `vsk` are set)

The uninitialized fields (including `pkt_len`, `remote_cid`,
`remote_port`, etc.) contain residual kernel stack data. This structure
is passed to `virtio_transport_send_pkt_info()`, which uses the
uninitialized fields.

Fixes: 06a8fc78367d ("VSOCK: Introduce virtio_vsock_common.ko")
Reported-by: TCS Robot <tcs_robot@tencent.com>
Signed-off-by: Henry Martin <bsdhenryma@tencent.com>
---
 net/vmw_vsock/virtio_transport_common.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index fe92e5fa95b4..cb391a98d025 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -1073,14 +1073,14 @@ EXPORT_SYMBOL_GPL(virtio_transport_connect);
 
 int virtio_transport_shutdown(struct vsock_sock *vsk, int mode)
 {
-	struct virtio_vsock_pkt_info info = {
-		.op = VIRTIO_VSOCK_OP_SHUTDOWN,
-		.flags = (mode & RCV_SHUTDOWN ?
-			  VIRTIO_VSOCK_SHUTDOWN_RCV : 0) |
-			 (mode & SEND_SHUTDOWN ?
-			  VIRTIO_VSOCK_SHUTDOWN_SEND : 0),
-		.vsk = vsk,
-	};
+	struct virtio_vsock_pkt_info info = {0};
+
+	info.op = VIRTIO_VSOCK_OP_SHUTDOWN;
+	info.flags = (mode & RCV_SHUTDOWN ?
+			VIRTIO_VSOCK_SHUTDOWN_RCV : 0) |
+			(mode & SEND_SHUTDOWN ?
+			VIRTIO_VSOCK_SHUTDOWN_SEND : 0);
+	info.vsk = vsk;
 
 	return virtio_transport_send_pkt_info(vsk, &info);
 }
-- 
2.41.3