Bluetooth: Fix incorrect strncpy() in hidp_setup_hid()

The length parameter should be sizeof(req->name) - 1 because there is no
guarantee that string provided by userspace will contain the trailing
'\0'.

Can be easily reproduced by manually setting req->name to 128 non-zero
bytes prior to ioctl(HIDPCONNADD) and checking the device name setup on
input subsystem:

$ cat /sys/devices/pnp0/00\:04/tty/ttyS0/hci0/hci0\:1/input8/name
AAAAAA[...]AAAAAAAAf0:af:f0:af:f0:af

("f0:af:f0:af:f0:af" is the device bluetooth address, taken from "phys"
field in struct hid_device due to overflow.)

Cc: stable@vger.kernel.org
Signed-off-by: Anderson Lizardo <anderson.lizardo@openbossa.org>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>

diff --git a/net/bluetooth/hidp/core.c b/net/bluetooth/hidp/core.c
index b2bcbe2dc328ba8473227035c39a7ff467ee5659..a7352ff3fd1e7884c2fc43142fba9bc0033063b8 100644 (file)
--- a/net/bluetooth/hidp/core.c
+++ b/net/bluetooth/hidp/core.c
@@ -931,7 +931,7 @@ static int hidp_setup_hid(struct hidp_session *session,
        hid->version = req->version;
        hid->country = req->country;
 
-       strncpy(hid->name, req->name, 128);
+       strncpy(hid->name, req->name, sizeof(req->name) - 1);
 
        snprintf(hid->phys, sizeof(hid->phys), "%pMR",
                 &bt_sk(session->ctrl_sock->sk)->src);