From: Guillaume Nault Date: Fri, 25 Aug 2017 14:22:17 +0000 (+0200) Subject: l2tp: initialise session's refcount before making it reachable X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=81beca86edb32fbf5cec019d522889b765539639;p=pandora-kernel.git l2tp: initialise session's refcount before making it reachable 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. Fixes: dbdbc73b4478 ("l2tp: fix duplicate session creation") Signed-off-by: Guillaume Nault Signed-off-by: David S. Miller [bwh: Backported to 3.2: keep using l2tp_session_inc_refcount()] Signed-off-by: Ben Hutchings --- diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c index 3954b18f42ee..8e74e693e8f8 100644 --- a/net/l2tp/l2tp_core.c +++ b/net/l2tp/l2tp_core.c @@ -1715,6 +1715,8 @@ 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); @@ -1722,10 +1724,6 @@ 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 */