From patchwork Wed Sep 19 12:22:10 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Simon Wunderlich X-Patchwork-Id: 17491 X-Patchwork-Delegate: sw@simonwunderlich.de Return-Path: X-Original-To: patchwork@open-mesh.org Delivered-To: patchwork@open-mesh.org Received: from open-mesh.org (localhost [IPv6:::1]) by open-mesh.org (Postfix) with ESMTP id B4EFA8301A; Wed, 19 Sep 2018 14:22:37 +0200 (CEST) Received-SPF: Pass (mailfrom) identity=mailfrom; client-ip=2001:4d88:2000:24::c0de; helo=mail.mail.packetmixer.de; envelope-from=sw@simonwunderlich.de; receiver= Received: from mail.mail.packetmixer.de (packetmixer.de [IPv6:2001:4d88:2000:24::c0de]) by open-mesh.org (Postfix) with ESMTPS id 0CD1C82FB7 for ; Wed, 19 Sep 2018 14:22:19 +0200 (CEST) Received: from kero.packetmixer.de (p200300C593D42E00B540A3BB6637942E.dip0.t-ipconnect.de [IPv6:2003:c5:93d4:2e00:b540:a3bb:6637:942e]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.mail.packetmixer.de (Postfix) with ESMTPSA id 858106205F; Wed, 19 Sep 2018 14:22:19 +0200 (CEST) From: Simon Wunderlich To: davem@davemloft.net Date: Wed, 19 Sep 2018 14:22:10 +0200 Message-Id: <20180919122213.23108-9-sw@simonwunderlich.de> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20180919122213.23108-1-sw@simonwunderlich.de> References: <20180919122213.23108-1-sw@simonwunderlich.de> Subject: [B.A.T.M.A.N.] [PATCH 08/11] batman-adv: Prevent duplicated tvlv handler X-BeenThere: b.a.t.m.a.n@lists.open-mesh.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: The list for a Better Approach To Mobile Ad-hoc Networking List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: The list for a Better Approach To Mobile Ad-hoc Networking Cc: netdev@vger.kernel.org, b.a.t.m.a.n@lists.open-mesh.org Errors-To: b.a.t.m.a.n-bounces@lists.open-mesh.org Sender: "B.A.T.M.A.N" From: Sven Eckelmann The function batadv_tvlv_handler_register is responsible for adding new tvlv_handler to the handler_list. It first checks whether the entry already is in the list or not. If it is, then the creation of a new entry is aborted. But the lock for the list is only held when the list is really modified. This could lead to duplicated entries because another context could create an entry with the same key between the check and the list manipulation. The check and the manipulation of the list must therefore be in the same locked code section. Fixes: ef26157747d4 ("batman-adv: tvlv - basic infrastructure") Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich --- net/batman-adv/tvlv.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/net/batman-adv/tvlv.c b/net/batman-adv/tvlv.c index a637458205d1..40e69c9346d2 100644 --- a/net/batman-adv/tvlv.c +++ b/net/batman-adv/tvlv.c @@ -529,15 +529,20 @@ void batadv_tvlv_handler_register(struct batadv_priv *bat_priv, { struct batadv_tvlv_handler *tvlv_handler; + spin_lock_bh(&bat_priv->tvlv.handler_list_lock); + tvlv_handler = batadv_tvlv_handler_get(bat_priv, type, version); if (tvlv_handler) { + spin_unlock_bh(&bat_priv->tvlv.handler_list_lock); batadv_tvlv_handler_put(tvlv_handler); return; } tvlv_handler = kzalloc(sizeof(*tvlv_handler), GFP_ATOMIC); - if (!tvlv_handler) + if (!tvlv_handler) { + spin_unlock_bh(&bat_priv->tvlv.handler_list_lock); return; + } tvlv_handler->ogm_handler = optr; tvlv_handler->unicast_handler = uptr; @@ -547,7 +552,6 @@ void batadv_tvlv_handler_register(struct batadv_priv *bat_priv, kref_init(&tvlv_handler->refcount); INIT_HLIST_NODE(&tvlv_handler->list); - spin_lock_bh(&bat_priv->tvlv.handler_list_lock); kref_get(&tvlv_handler->refcount); hlist_add_head_rcu(&tvlv_handler->list, &bat_priv->tvlv.handler_list); spin_unlock_bh(&bat_priv->tvlv.handler_list_lock);