From patchwork Sat May 21 09:48:17 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Antonio Quartulli X-Patchwork-Id: 16263 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 0C668816E5; Sat, 21 May 2016 11:49:20 +0200 (CEST) Authentication-Results: open-mesh.org; dmarc=none header.from=unstable.cc Received-SPF: Permerror (SPF Permanent Error: Two or more type TXT spf records found.) identity=mailfrom; client-ip=5.148.176.60; helo=s2.neomailbox.net; envelope-from=a@unstable.cc; receiver=b.a.t.m.a.n@lists.open-mesh.org Authentication-Results: open-mesh.org; dmarc=none header.from=unstable.cc Received: from s2.neomailbox.net (s2.neomailbox.net [5.148.176.60]) by open-mesh.org (Postfix) with ESMTPS id 15F4481698 for ; Sat, 21 May 2016 11:49:15 +0200 (CEST) From: Antonio Quartulli To: stable@vger.kernel.org Date: Sat, 21 May 2016 17:48:17 +0800 Message-Id: <20160521094817.401-1-a@unstable.cc> Cc: b.a.t.m.a.n@lists.open-mesh.org, Antonio Quartulli Subject: [B.A.T.M.A.N.] [PATCH stable-4.6] batman-adv: Fix double neigh_node_put in batadv_v_ogm_route_update X-BeenThere: b.a.t.m.a.n@lists.open-mesh.org X-Mailman-Version: 2.1.18 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 Errors-To: b.a.t.m.a.n-bounces@lists.open-mesh.org Sender: "B.A.T.M.A.N" From: Sven Eckelmann The router is put down twice when it was non-NULL and either orig_ifinfo is NULL afterwards or batman-adv receives a packet with the same sequence number. This will end up in a use-after-free when the batadv_neigh_node is removed because the reference counter ended up too early at 0. Fixes: 9323158ef9f4 ("batman-adv: OGMv2 - implement originators logic") Signed-off-by: Sven Eckelmann Signed-off-by: Antonio Quartulli --- This patch is skipping netdev and is being sent directly to stable in accordance with David S. Miller[1]. The reason is that this patch applies only on linux-4.6 and not on linux-4.7/net because it was "accidentally" fixed by a refactoring commit (more details in [2]). It addresses a reference imbalance which systematically leads to a use-after-free and then a kernel crash. Cheers, [1] https://www.mail-archive.com/b.a.t.m.a.n@lists.open-mesh.org/msg15258.html [2] https://www.mail-archive.com/b.a.t.m.a.n@lists.open-mesh.org/msg15252.html net/batman-adv/bat_v_ogm.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/batman-adv/bat_v_ogm.c b/net/batman-adv/bat_v_ogm.c index d9bcbe6e7d65..91df28a100f9 100644 --- a/net/batman-adv/bat_v_ogm.c +++ b/net/batman-adv/bat_v_ogm.c @@ -529,8 +529,10 @@ static void batadv_v_ogm_route_update(struct batadv_priv *bat_priv, goto out; } - if (router) + if (router) { batadv_neigh_node_put(router); + router = NULL; + } /* Update routes, and check if the OGM is from the best next hop */ batadv_v_ogm_orig_update(bat_priv, orig_node, neigh_node, ogm2,