bt: sync with caf kk_2.7_rb-1.42

* except for bluesleep

Change-Id: I2d737fedf3b6b083ba2739fa27a0ac6874769754
(cherry picked from commit 4366735eed1528268f20d02cc94163915ce36554)
Bluetooth: fix possible info leak in bt_sock_recvmsg()

[ Upstream commit 4683f42fde3977bdb4e8a09622788cc8b5313778 ]

In case the socket is already shutting down, bt_sock_recvmsg() returns
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 msg_namelen assignment in front of the shutdown
test.

Change-Id: If9dbd8259b0e5db3837e55dd3725087aac817667
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 771e1f203b72ea4e4697c40dbfb08eb018ad6603)