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

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>

1 files changed, 1 insertions, 0 deletions

diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c
index 7e1e59645c05..64f55ca61472 100644
--- a/net/bluetooth/rfcomm/sock.c
+++ b/net/bluetooth/rfcomm/sock.c
@@ -822,6 +822,7 @@ 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))