Some subsystems, like BPF SOCKMAP, set sk_user_data without actually setting the encap_type. For this reason, we must make sure that the type is the one ovpn expects before dereferencing sk_user_data. Failing to do so may lead to out-of-bounds reads. Fixes: f6226ae7a0cd ("ovpn: introduce the ovpn_socket object") Signed-off-by: Antonio Quartulli --- drivers/net/ovpn/socket.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/net/ovpn/socket.c b/drivers/net/ovpn/socket.c index 517caa64a4fe..6cbeb2caaeec 100644 --- a/drivers/net/ovpn/socket.c +++ b/drivers/net/ovpn/socket.c @@ -162,6 +162,15 @@ struct ovpn_socket *ovpn_socket_new(struct socket *sock, struct ovpn_peer *peer) rcu_read_lock(); ovpn_sock = rcu_dereference_sk_user_data(sk); if (ovpn_sock) { + /* something else filled the sk_user_data without + * setting the encap_type. Reject the socket. + */ + if (!type) { + ovpn_sock = ERR_PTR(-EBUSY); + rcu_read_unlock(); + goto sock_release; + } + /* socket owned by another ovpn instance, we can't use it */ if (ovpn_sock->ovpn != peer->ovpn) { ovpn_sock = ERR_PTR(-EBUSY); -- 2.54.0