From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0DE93C677D4 for ; Mon, 8 Oct 2018 15:33:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AE85421557 for ; Mon, 8 Oct 2018 15:33:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="G6u/9Jht" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AE85421557 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728727AbeJHWpn (ORCPT ); Mon, 8 Oct 2018 18:45:43 -0400 Received: from mail.kernel.org ([198.145.29.99]:57552 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727747AbeJHWiv (ORCPT ); Mon, 8 Oct 2018 18:38:51 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4F0252089D; Mon, 8 Oct 2018 15:26:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1539012395; bh=hFIa8GqarBjG7dVbOUgEc2lFnrUxRlkI3+aSl3O9hz0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=G6u/9Jht4I6CY/UvS+SE9bHLWdYx1hDwc16uoUy+lVXeAHLu0WFeY5fekS1LMZ/RL XVQ77sdDHWbRH9fB2g63EgJqoNh/vjnpfRtfxCA5ocd78VswOtbj7VcRwo9vDmrrYR DIUnSyONAMTMBCZB2O7OPfTlL+/5vQq7PMjU77lo= From: Sasha Levin To: stable@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Sven Eckelmann , Simon Wunderlich , Sasha Levin Subject: [PATCH AUTOSEL 4.14 05/32] batman-adv: Prevent duplicated gateway_node entry Date: Mon, 8 Oct 2018 11:26:02 -0400 Message-Id: <20181008152629.70812-5-sashal@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20181008152629.70812-1-sashal@kernel.org> References: <20181008152629.70812-1-sashal@kernel.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sven Eckelmann [ Upstream commit dff9bc42ab0b2d38c5e90ddd79b238fed5b4c7ad ] The function batadv_gw_node_add is responsible for adding new gw_node to the gateway_list. It is expecting that the caller already checked that there is not already an entry with the same key or not. 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: c6c8fea29769 ("net: Add batman-adv meshing protocol") Signed-off-by: Sven Eckelmann Acked-by: Marek Lindner Signed-off-by: Simon Wunderlich Signed-off-by: Sasha Levin --- net/batman-adv/gateway_client.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/net/batman-adv/gateway_client.c b/net/batman-adv/gateway_client.c index 06276ae9f752..c6a7341f0527 100644 --- a/net/batman-adv/gateway_client.c +++ b/net/batman-adv/gateway_client.c @@ -31,6 +31,7 @@ #include #include #include +#include #include #include #include @@ -325,6 +326,9 @@ void batadv_gw_check_election(struct batadv_priv *bat_priv, * @bat_priv: the bat priv with all the soft interface information * @orig_node: originator announcing gateway capabilities * @gateway: announced bandwidth information + * + * Has to be called with the appropriate locks being acquired + * (gw.list_lock). */ static void batadv_gw_node_add(struct batadv_priv *bat_priv, struct batadv_orig_node *orig_node, @@ -332,6 +336,8 @@ static void batadv_gw_node_add(struct batadv_priv *bat_priv, { struct batadv_gw_node *gw_node; + lockdep_assert_held(&bat_priv->gw.list_lock); + if (gateway->bandwidth_down == 0) return; @@ -346,10 +352,8 @@ static void batadv_gw_node_add(struct batadv_priv *bat_priv, gw_node->bandwidth_down = ntohl(gateway->bandwidth_down); gw_node->bandwidth_up = ntohl(gateway->bandwidth_up); - spin_lock_bh(&bat_priv->gw.list_lock); kref_get(&gw_node->refcount); hlist_add_head_rcu(&gw_node->list, &bat_priv->gw.gateway_list); - spin_unlock_bh(&bat_priv->gw.list_lock); batadv_dbg(BATADV_DBG_BATMAN, bat_priv, "Found new gateway %pM -> gw bandwidth: %u.%u/%u.%u MBit\n", @@ -405,11 +409,14 @@ void batadv_gw_node_update(struct batadv_priv *bat_priv, { struct batadv_gw_node *gw_node, *curr_gw = NULL; + spin_lock_bh(&bat_priv->gw.list_lock); gw_node = batadv_gw_node_get(bat_priv, orig_node); if (!gw_node) { batadv_gw_node_add(bat_priv, orig_node, gateway); + spin_unlock_bh(&bat_priv->gw.list_lock); goto out; } + spin_unlock_bh(&bat_priv->gw.list_lock); if ((gw_node->bandwidth_down == ntohl(gateway->bandwidth_down)) && (gw_node->bandwidth_up == ntohl(gateway->bandwidth_up))) -- 2.17.1