From 680d04e0ba7e926233e3b9cee59125ce181f66ba Mon Sep 17 00:00:00 2001 From: Mathias Krause Date: Sun, 7 Apr 2013 01:52:01 +0000 Subject: [PATCH] VSOCK: vmci - fix possible info leak in vmci_transport_dgram_dequeue() In case we received no data on the call to skb_recv_datagram(), i.e. skb->data is NULL, vmci_transport_dgram_dequeue() will return with 0 without updating msg_namelen leading to net/socket.c leaking the local, uninitialized sockaddr_storage variable to userland -- 128 bytes of kernel stack memory. Fix this by moving the already existing msg_namelen assignment a few lines above. Cc: Andy King Cc: Dmitry Torokhov Cc: George Zhang Signed-off-by: Mathias Krause Signed-off-by: David S. Miller --- net/vmw_vsock/vmci_transport.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/vmw_vsock/vmci_transport.c b/net/vmw_vsock/vmci_transport.c index 1f6508e249ae..5e04d3d96285 100644 --- a/net/vmw_vsock/vmci_transport.c +++ b/net/vmw_vsock/vmci_transport.c @@ -1736,6 +1736,8 @@ static int vmci_transport_dgram_dequeue(struct kiocb *kiocb, if (flags & MSG_OOB || flags & MSG_ERRQUEUE) return -EOPNOTSUPP; + msg->msg_namelen = 0; + /* Retrieve the head sk_buff from the socket's receive queue. */ err = 0; skb = skb_recv_datagram(&vsk->sk, flags, noblock, &err); @@ -1768,7 +1770,6 @@ static int vmci_transport_dgram_dequeue(struct kiocb *kiocb, if (err) goto out; - msg->msg_namelen = 0; if (msg->msg_name) { struct sockaddr_vm *vm_addr; -- 2.20.1