Code: static int sco_sock_getsockopt_old(struct socket *sock, int optname, char __user *optval, int __user *optlen)
{
	struct sock *sk = sock->sk;
	struct sco_options opts;
	struct sco_conninfo cinfo;
	int len, err = 0;

	BT_DBG("sk %p", sk);

	if (get_user(len, optlen))
		return -EFAULT;

	lock_sock(sk);

	switch (optname) {
	case SCO_OPTIONS:
		if (sk->sk_state != BT_CONNECTED) {
			err = -ENOTCONN;
			break;
		}

		opts.mtu = sco_pi(sk)->conn->mtu;

		BT_DBG("mtu %d", opts.mtu);

		len = min_t(unsigned int, len, sizeof(opts));
		if (copy_to_user(optval, (char *)&opts, len))
			err = -EFAULT;

		break;

	case SCO_CONNINFO:
		if (sk->sk_state != BT_CONNECTED) {
			err = -ENOTCONN;
 			break;
 		}
 
 		cinfo.hci_handle = sco_pi(sk)->conn->hcon->handle;
 		memcpy(cinfo.dev_class, sco_pi(sk)->conn->hcon->dev_class, 3);
 
		len = min_t(unsigned int, len, sizeof(cinfo));
		if (copy_to_user(optval, (char *)&cinfo, len))
			err = -EFAULT;

		break;

	default:
		err = -ENOPROTOOPT;
		break;
	}

	release_sock(sk);
	return err;
}

Vulnerability Type: +Info 
CWE ID: CWE-200
Summary: The sco_sock_getsockopt_old function in net/bluetooth/sco.c in the Linux kernel before 2.6.39 does not initialize a certain structure, which allows local users to obtain potentially sensitive information from kernel stack memory via the SCO_CONNINFO option.
Commit Message: Bluetooth: sco: fix information leak to userspace

struct sco_conninfo has one padding byte in the end.  Local variable
cinfo of type sco_conninfo is copied to userspace with this uninizialized
one byte, leading to old stack contents leak.

Signed-off-by: Vasiliy Kulikov <segoon@openwall.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>