Bluetooth: RFCOMM - Fix info leak via getsockname()

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 <[e-mail]>
Cc: Marcel Holtmann <[e-mail]>
Cc: Gustavo Padovan <[e-mail]>
Cc: Johan Hedberg <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/bluetooth/rfcomm/sock.c

···
 
 	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)