3.8-stable review patch.  If anyone has any objections, please let me know.

------------------


From: Mathias Krause <mini...@googlemail.com>

[ 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.

Signed-off-by: Mathias Krause <mini...@googlemail.com>
Cc: Marcel Holtmann <mar...@holtmann.org>
Cc: Gustavo Padovan <gust...@padovan.org>
Cc: Johan Hedberg <johan.hedb...@gmail.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 net/bluetooth/af_bluetooth.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/net/bluetooth/af_bluetooth.c
+++ b/net/bluetooth/af_bluetooth.c
@@ -230,6 +230,8 @@ int bt_sock_recvmsg(struct kiocb *iocb,
        if (flags & (MSG_OOB))
                return -EOPNOTSUPP;
 
+       msg->msg_namelen = 0;
+
        skb = skb_recv_datagram(sk, flags, noblock, &err);
        if (!skb) {
                if (sk->sk_shutdown & RCV_SHUTDOWN)
@@ -237,8 +239,6 @@ int bt_sock_recvmsg(struct kiocb *iocb,
                return err;
        }
 
-       msg->msg_namelen = 0;
-
        copied = skb->len;
        if (len < copied) {
                msg->msg_flags |= MSG_TRUNC;


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