Code: static int sco_sock_recvmsg(struct kiocb *iocb, struct socket *sock,
			    struct msghdr *msg, size_t len, int flags)
{
	struct sock *sk = sock->sk;
	struct sco_pinfo *pi = sco_pi(sk);

	lock_sock(sk);

	if (sk->sk_state == BT_CONNECT2 &&
 	    test_bit(BT_SK_DEFER_SETUP, &bt_sk(sk)->flags)) {
 		hci_conn_accept(pi->conn->hcon, 0);
 		sk->sk_state = BT_CONFIG;
 
 		release_sock(sk);
 		return 0;
	}

	release_sock(sk);

	return bt_sock_recvmsg(iocb, sock, msg, len, flags);
}

Vulnerability Type: +Info 
CWE ID: CWE-200
Summary: The sco_sock_recvmsg function in net/bluetooth/sco.c in the Linux kernel before 3.9-rc7 does not initialize a certain length variable, which allows local users to obtain sensitive information from kernel stack memory via a crafted recvmsg or recvfrom system call.
Commit Message: Bluetooth: SCO - Fix missing msg_namelen update in sco_sock_recvmsg()

If the socket is in state BT_CONNECT2 and BT_SK_DEFER_SETUP is set in
the flags, sco_sock_recvmsg() returns early with 0 without updating the
possibly set msg_namelen member. This, in turn, leads to a 128 byte
kernel stack leak in net/socket.c.

Fix this by updating msg_namelen in this case. For all other cases it
will be handled in bt_sock_recvmsg().

Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: Gustavo Padovan <gustavo@padovan.org>
Cc: Johan Hedberg <johan.hedberg@gmail.com>
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>