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

diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c
index 64f55ca614722f1d3933a7d00239c7d4bee8efa3..1a17850d093cd652621ac54833c53b8dabd395bc 100644 (file)
--- a/net/bluetooth/rfcomm/sock.c
+++ b/net/bluetooth/rfcomm/sock.c
@@ -528,6 +528,7 @@ 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)