Code: static int rfcomm_sock_getsockopt(struct socket *sock, int level, int optname, char __user *optval, int __user *optlen)
{
	struct sock *sk = sock->sk;
	struct bt_security sec;
	int len, err = 0;

	BT_DBG("sk %p", sk);

	if (level == SOL_RFCOMM)
		return rfcomm_sock_getsockopt_old(sock, optname, optval, optlen);

	if (level != SOL_BLUETOOTH)
		return -ENOPROTOOPT;

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

	lock_sock(sk);

	switch (optname) {
	case BT_SECURITY:
		if (sk->sk_type != SOCK_STREAM) {
			err = -EINVAL;
			break;
 		}
 
 		sec.level = rfcomm_pi(sk)->sec_level;
 
 		len = min_t(unsigned int, len, sizeof(sec));
 		if (copy_to_user(optval, (char *) &sec, len))
			err = -EFAULT;

		break;

	case BT_DEFER_SETUP:
		if (sk->sk_state != BT_BOUND && sk->sk_state != BT_LISTEN) {
			err = -EINVAL;
			break;
		}

		if (put_user(test_bit(BT_SK_DEFER_SETUP, &bt_sk(sk)->flags),
			     (u32 __user *) optval))
			err = -EFAULT;

		break;

	default:
		err = -ENOPROTOOPT;
		break;
	}

	release_sock(sk);
	return err;
}

Vulnerability Type: +Info 
CWE ID: CWE-200
Summary: The Bluetooth RFCOMM implementation in the Linux kernel before 3.6 does not properly initialize certain structures, which allows local users to obtain sensitive information from kernel memory via a crafted application.
Commit Message: Bluetooth: RFCOMM - Fix info leak in getsockopt(BT_SECURITY)

The RFCOMM code fails to initialize the key_size member of struct
bt_security before copying it to userland -- that for leaking one
byte kernel stack. Initialize key_size with 0 to avoid the info
leak.

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