Patchwork [15/16] VSOCK: vmci - fix possible info leak in vmci_transport_dgram_dequeue()

login
register
mail settings
Submitter Mathias Krause
Date April 7, 2013, 11:52 a.m.
Message ID <1365335522-29931-16-git-send-email-minipli@googlemail.com>
Download mbox | patch
Permalink /patch/234488/
State Accepted
Delegated to: David Miller
Headers show

Comments

Mathias Krause - April 7, 2013, 11:52 a.m.
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 <acking@vmware.com>
Cc: Dmitry Torokhov <dtor@vmware.com>
Cc: George Zhang <georgezhang@vmware.com>
Signed-off-by: Mathias Krause <minipli@googlemail.com>
---
 net/vmw_vsock/vmci_transport.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Patch

diff --git a/net/vmw_vsock/vmci_transport.c b/net/vmw_vsock/vmci_transport.c
index a70ace8..a8e4e70 100644
--- a/net/vmw_vsock/vmci_transport.c
+++ b/net/vmw_vsock/vmci_transport.c
@@ -1727,6 +1727,8 @@  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);
@@ -1759,7 +1761,6 @@  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;