From: Guillaume Nault g.nault@alphalink.fr
commit 9ee369a405c57613d7c83a3967780c3e30c52ecc upstream.
Sessions must be fully initialised before calling l2tp_session_add_to_tunnel(). Otherwise, there's a short time frame where partially initialised sessions can be accessed by external users.
Backporting Notes
l2tp_core.c: moving code that had been converted from atomic to refcount_t by an earlier change (which isn't being included in this patch series).
Fixes: dbdbc73b4478 ("l2tp: fix duplicate session creation") Signed-off-by: Guillaume Nault g.nault@alphalink.fr Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Giuliano Procida gprocida@google.com --- net/l2tp/l2tp_core.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c index a9d4d42e2ef6..7f72957405b8 100644 --- a/net/l2tp/l2tp_core.c +++ b/net/l2tp/l2tp_core.c @@ -1847,6 +1847,8 @@ struct l2tp_session *l2tp_session_create(int priv_size, struct l2tp_tunnel *tunn
l2tp_session_set_header_len(session, tunnel->version);
+ l2tp_session_inc_refcount(session); + err = l2tp_session_add_to_tunnel(tunnel, session); if (err) { kfree(session); @@ -1854,10 +1856,6 @@ struct l2tp_session *l2tp_session_create(int priv_size, struct l2tp_tunnel *tunn return ERR_PTR(err); }
- /* Bump the reference count. The session context is deleted - * only when this drops to zero. - */ - l2tp_session_inc_refcount(session); l2tp_tunnel_inc_refcount(tunnel);
/* Ensure tunnel socket isn't deleted */