Bluetooth: hidp: fix buffer overflow

BugLink: https://bugs.launchpad.net/bugs/1830176

commit a1616a5a upstream.

Struct ca is copied from userspace. It is not checked whether the "name"
field is NULL terminated, which allows local users to obtain potentially
sensitive information from kernel stack memory, via a HIDPCONNADD command.

This vulnerability is similar to CVE-2011-1079.
Signed-off-by: Young Xiao <YangX92@hotmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

net/bluetooth/hidp/sock.c

@@ -76,6 +76,7 @@ static int hidp_sock_ioctl(struct socket *sock, unsigned int cmd, unsigned long
 			sockfd_put(csock);
 			return err;
 		}
+		ca.name[sizeof(ca.name)-1] = 0;
 
 		err = hidp_connection_add(&ca, csock, isock);
 		if (!err && copy_to_user(argp, &ca, sizeof(ca)))