[v2.6.34-stable 130/213] Bluetooth: RFCOMM - Fix info leak via getsockname()

[Paul Gortmaker]

From: Mathias Krause <minipli@xxxxxxxxxxxxxx>

                   -------------------
    This is a commit scheduled for the next v2.6.34 longterm release.
    http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git
    If you see a problem with using this for longterm, please comment.
                   -------------------

commit 9344a972961d1a6d2c04d9008b13617bcb6ec2ef upstream.

The RFCOMM code fails to initialize the trailing padding byte of struct
sockaddr_rc added for alignment. It that for leaks one byte kernel stack
via the getsockname() syscall. Add an explicit memset(0) before filling
the structure to avoid the info leak.

Signed-off-by: Mathias Krause <minipli@xxxxxxxxxxxxxx>
Cc: Marcel Holtmann <marcel@xxxxxxxxxxxx>
Cc: Gustavo Padovan <gustavo@xxxxxxxxxxx>
Cc: Johan Hedberg <johan.hedberg@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
---
 net/bluetooth/rfcomm/sock.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c
index b045bbbc2353..92aa7a012110 100644
--- a/net/bluetooth/rfcomm/sock.c
+++ b/net/bluetooth/rfcomm/sock.c
@@ -547,6 +547,7 @@ static int rfcomm_sock_getname(struct socket *sock, struct sockaddr *addr, int *
 
 	BT_DBG("sock %p, sk %p", sock, sk);
 
+	memset(sa, 0, sizeof(*sa));
 	sa->rc_family  = AF_BLUETOOTH;
 	sa->rc_channel = rfcomm_pi(sk)->channel;
 	if (peer)
-- 
1.8.5.2

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