Bluetooth: RFCOMM - Fix info leak in getsockopt(BT_SECURITY)

[ Upstream commit 9ad2de43f1aee7e7274a4e0d41465489299e344b ]

The RFCOMM code fails to initialize the key_size member of struct
bt_security before copying it to userland -- that for leaking one
byte kernel stack. Initialize key_size with 0 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 5417f6127323ec0db7cb51d75eb1e643fb8ec339..03584bc0ede4380ed1929982449e9e9a13023b38 100644 (file)
--- a/net/bluetooth/rfcomm/sock.c
+++ b/net/bluetooth/rfcomm/sock.c
@@ -835,6 +835,7 @@ static int rfcomm_sock_getsockopt(struct socket *sock, int level, int optname, c
                }
 
                sec.level = rfcomm_pi(sk)->sec_level;
+               sec.key_size = 0;
 
                len = min_t(unsigned int, len, sizeof(sec));
                if (copy_to_user(optval, (char *) &sec, len))