| Message ID | 89a39d08a4722ac050d28b07333ca096786812f6.1528887257.git.g.nault@alphalink.fr |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
| Series | l2tp: pppol2tp_connect() fixes | expand |
diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c index 270a0a999eaf..8b3b6947a07d 100644 --- a/net/l2tp/l2tp_ppp.c +++ b/net/l2tp/l2tp_ppp.c @@ -734,6 +734,12 @@ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr, session = l2tp_session_get(sock_net(sk), tunnel, session_id); if (session) { drop_refcnt = true; + + if (session->pwtype != L2TP_PWTYPE_PPP) { + error = -EPROTOTYPE; + goto end; + } + ps = l2tp_session_priv(session); /* Using a pre-existing session is fine as long as it hasn't
l2tp_session_priv() returns a struct pppol2tp_session pointer only for PPPoL2TP sessions. In particular, if the session is an L2TP_PWTYPE_ETH pseudo-wire, l2tp_session_priv() returns a pointer to an l2tp_eth_sess structure, which is much smaller than struct pppol2tp_session. This leads to invalid memory dereference when trying to lock ps->sk_lock. Fixes: d9e31d17ceba ("l2tp: Add L2TP ethernet pseudowire support") Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> --- net/l2tp/l2tp_ppp.c | 6 ++++++ 1 file changed, 6 insertions(+)