Commit 695ad876 authored Jun 15, 2018 by David S. Miller

Merge branch 'l2tp-l2tp_ppp-must-ignore-non-PPP-sessions'



Guillaume Nault says:

====================
l2tp: l2tp_ppp must ignore non-PPP sessions

The original L2TP code was written for version 2 of the protocol, which
could only carry PPP sessions. Then L2TPv3 generalised the protocol so that
it could transport different kinds of pseudo-wires. But parts of the
l2tp_ppp module still break in presence of non-PPP sessions.

Assuming L2TPv2 tunnels can only transport PPP sessions is right, but
l2tp_netlink failed to ensure that (fixed in patch 1).
When retrieving a session from an arbitrary tunnel, l2tp_ppp needs to
filter out non-PPP sessions (last occurrence fixed in patch 2).
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

parents eab9a2d5 ecd012e4

net/l2tp/l2tp_netlink.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -553,6 +553,12 @@ static int l2tp_nl_cmd_session_create(struct sk_buff skb, struct genl_info inf
		goto out_tunnel;
		}

		/* L2TPv2 only accepts PPP pseudo-wires */
		if (tunnel->version == 2 && cfg.pw_type != L2TP_PWTYPE_PPP) {
		ret = -EPROTONOSUPPORT;
		goto out_tunnel;
		}

		if (tunnel->version > 2) {
		if (info->attrs[L2TP_ATTR_DATA_SEQ])
		cfg.data_seq = nla_get_u8(info->attrs[L2TP_ATTR_DATA_SEQ]);

net/l2tp/l2tp_ppp.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -1201,7 +1201,7 @@ static int pppol2tp_tunnel_ioctl(struct l2tp_tunnel *tunnel,
		l2tp_session_get(sock_net(sk), tunnel,
		stats.session_id);

		if (session) {
		if (session && session->pwtype == L2TP_PWTYPE_PPP) {
		err = pppol2tp_session_ioctl(session, cmd,
		arg);
		l2tp_session_dec_refcount(session);