From patchwork Sun Aug 12 19:04:43 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sven Eckelmann X-Patchwork-Id: 17458 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 693EB82D9D; Sun, 12 Aug 2018 21:05:00 +0200 (CEST) Authentication-Results: open-mesh.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=narfation.org header.i=@narfation.org header.b="U7MlPcWE"; dkim-atps=neutral Received-SPF: Pass (mailfrom) identity=mailfrom; client-ip=79.140.41.39; helo=v3-1039.vlinux.de; envelope-from=sven@narfation.org; receiver= Received: from v3-1039.vlinux.de (narfation.org [79.140.41.39]) by open-mesh.org (Postfix) with ESMTPS id 15F1782D42 for ; Sun, 12 Aug 2018 21:04:57 +0200 (CEST) Received: from sven-desktop.home.narfation.org (p200300C593C7FBFD0000000000008096.dip0.t-ipconnect.de [IPv6:2003:c5:93c7:fbfd::8096]) by v3-1039.vlinux.de (Postfix) with ESMTPSA id 8D014110135; Sun, 12 Aug 2018 21:04:56 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=narfation.org; s=20121; t=1534100696; bh=p3JCBT3gNSr5EKIaO4rk7g2VekxUw9yQZ6BwAioul0E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=U7MlPcWEuqaQuGKnWUoRuRMlElaxjaoGEh5Yf0yja2C/NkO4lUhvWfXzs1vIrAeNp a0T0GgJYOr0vSglzWJfMxgXuJvDB/6BB7UxptL3Owq8kXUfiHGDVRoNVhDUXqhI698 72xC2UzPV14STKrpjfkSiUL7+/hqS5wstxLWOS5A= From: Sven Eckelmann To: b.a.t.m.a.n@lists.open-mesh.org Date: Sun, 12 Aug 2018 21:04:43 +0200 Message-Id: <20180812190445.28013-4-sven@narfation.org> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20180812190445.28013-1-sven@narfation.org> References: <20180812190445.28013-1-sven@narfation.org> Subject: [B.A.T.M.A.N.] [PATCH 3/5] batman-adv: Prevent duplicated softif_vlan entry 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 Errors-To: b.a.t.m.a.n-bounces@lists.open-mesh.org Sender: "B.A.T.M.A.N" The function batadv_softif_vlan_get is responsible for adding new softif_vlan to the softif_vlan_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: 952cebb57518 ("batman-adv: add per VLAN interface attribute framework") Signed-off-by: Sven Eckelmann --- net/batman-adv/soft-interface.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c index 1485263a..426a98bf 100644 --- a/net/batman-adv/soft-interface.c +++ b/net/batman-adv/soft-interface.c @@ -572,17 +572,21 @@ struct batadv_softif_vlan *batadv_softif_vlan_get(struct batadv_priv *bat_priv, int batadv_softif_create_vlan(struct batadv_priv *bat_priv, unsigned short vid) { struct batadv_softif_vlan *vlan; - int err; + + spin_lock_bh(&bat_priv->softif_vlan_list_lock); vlan = batadv_softif_vlan_get(bat_priv, vid); if (vlan) { batadv_softif_vlan_put(vlan); + spin_unlock_bh(&bat_priv->softif_vlan_list_lock); return -EEXIST; } vlan = kzalloc(sizeof(*vlan), GFP_ATOMIC); - if (!vlan) + if (!vlan) { + spin_unlock_bh(&bat_priv->softif_vlan_list_lock); return -ENOMEM; + } vlan->bat_priv = bat_priv; vlan->vid = vid; @@ -590,17 +594,16 @@ int batadv_softif_create_vlan(struct batadv_priv *bat_priv, unsigned short vid) atomic_set(&vlan->ap_isolation, 0); - err = batadv_sysfs_add_vlan(bat_priv->soft_iface, vlan); - if (err) { - kfree(vlan); - return err; - } - - spin_lock_bh(&bat_priv->softif_vlan_list_lock); kref_get(&vlan->refcount); hlist_add_head_rcu(&vlan->list, &bat_priv->softif_vlan_list); spin_unlock_bh(&bat_priv->softif_vlan_list_lock); + /* adding sysfs can fail but it is now to late to handle it. + * it can also not be in the spinlock section due to the sleeping + * behavior of the sysfs functions and the fs_reclaim lock + */ + batadv_sysfs_add_vlan(bat_priv->soft_iface, vlan); + /* add a new TT local entry. This one will be marked with the NOPURGE * flag */