Bluetooth: RFCOMM - Fix info leak via getsockname()

[ Upstream commit 9344a972961d1a6d2c04d9008b13617bcb6ec2ef ]

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@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: Ben Hutchings <ben@decadent.org.uk>

diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c
index 03584bc..7ee4ead 100644 (file)
--- 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)