l2tp: fix race in l2tp_recv_common()
commit 61b9a047729bb230978178bca6729689d0c50ca2 upstream.
Taking a reference on sessions in l2tp_recv_common() is racy; this
has to be done by the callers.
To this end, a new function is required (l2tp_session_get()) to
atomically lookup a session and take a reference on it. Callers then
have to manually drop this reference.
Fixes: fd558d186df2 ("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>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/net/l2tp/l2tp_core.h b/net/l2tp/l2tp_core.h
index e7233ba..1d02050 100644
--- a/net/l2tp/l2tp_core.h
+++ b/net/l2tp/l2tp_core.h
@@ -240,6 +240,9 @@
return tunnel;
}
+struct l2tp_session *l2tp_session_get(struct net *net,
+ struct l2tp_tunnel *tunnel,
+ u32 session_id, bool do_ref);
struct l2tp_session *l2tp_session_find(struct net *net,
struct l2tp_tunnel *tunnel,
u32 session_id);