Commit 57377d63 authored Mar 31, 2017 by Guillaume Nault Committed by David S. Miller Apr 01, 2017

l2tp: ensure session can't get removed during pppol2tp_session_ioctl()

Holding a reference on session is required before calling
pppol2tp_session_ioctl(). The session could get freed while processing the
ioctl otherwise. Since pppol2tp_session_ioctl() uses the session's socket,
we also need to take a reference on it in l2tp_session_get().

Fixes: fd558d18 ("l2tp: Split pppol2tp patch into separate l2tp and ppp parts")
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 61b9a047

net/l2tp/l2tp_ppp.c

+11 −4

Original line number	Diff line number	Diff line
		@@ -1141,11 +1141,18 @@ static int pppol2tp_tunnel_ioctl(struct l2tp_tunnel *tunnel,
		if (stats.session_id != 0) {
		/* resend to session ioctl handler */
		struct l2tp_session *session =
		l2tp_session_find(sock_net(sk), tunnel, stats.session_id);
		if (session != NULL)
		err = pppol2tp_session_ioctl(session, cmd, arg);
		else
		l2tp_session_get(sock_net(sk), tunnel,
		stats.session_id, true);

		if (session) {
		err = pppol2tp_session_ioctl(session, cmd,
		arg);
		if (session->deref)
		session->deref(session);
		l2tp_session_dec_refcount(session);
		} else {
		err = -EBADR;
		}
		break;
		}
		#ifdef CONFIG_XFRM