From patchwork Thu Mar 19 13:00:21 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 228952 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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 830D8C4332B for ; Thu, 19 Mar 2020 13:36:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 58B2720663 for ; Thu, 19 Mar 2020 13:36:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584625002; bh=7XS8OHBApcyUM7SsocyIfhCZel6pYeXzBAVonk65o3c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=DOcxypGl1TiQLDnG2D9KR2kHLfnZiqdM7wsdM0qPfWScCiLheyPZdCIyCgN2Uofvq aF1XhnhlWUXmDpqchAKUHNj+civcSCQFTA2TPYpo2Fok1eg6Nbe79TVjtC2lS9+PuV 1YpXDQgF2/zN3L+zTsOQPnU/3gCCO4towumADGlM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728307AbgCSNJV (ORCPT ); Thu, 19 Mar 2020 09:09:21 -0400 Received: from mail.kernel.org ([198.145.29.99]:53766 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728301AbgCSNJU (ORCPT ); Thu, 19 Mar 2020 09:09:20 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C16F520722; Thu, 19 Mar 2020 13:09:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584623360; bh=7XS8OHBApcyUM7SsocyIfhCZel6pYeXzBAVonk65o3c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ADHoD+/kxiDQcWpY99KxKNmftimW6ttiR2A8pnLrun/rnGi1LbAP7AltP/M5eCPVW 834mZeAdVOCtLKXqqCx/2ydDlxsO+R2V9x+P+lkntU7VWATdWGtN76S1ZE6UA2W6sj kYavXkll9fQHFJVXMWQTWHzeQ10Fq1aQxQe8htiU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , Sven Eckelmann , Marek Lindner , Simon Wunderlich Subject: [PATCH 4.4 77/93] batman-adv: Prevent duplicated nc_node entry Date: Thu, 19 Mar 2020 14:00:21 +0100 Message-Id: <20200319123949.150591940@linuxfoundation.org> X-Mailer: git-send-email 2.25.2 In-Reply-To: <20200319123924.795019515@linuxfoundation.org> References: <20200319123924.795019515@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Sven Eckelmann commit fa122fec8640eb7186ce5a41b83a4c1744ceef8f upstream. The function batadv_nc_get_nc_node is responsible for adding new nc_nodes to the in_coding_list and out_coding_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: d56b1705e28c ("batman-adv: network coding - detect coding nodes and remove these after timeout") Signed-off-by: Sven Eckelmann Acked-by: Marek Lindner Signed-off-by: Simon Wunderlich Signed-off-by: Greg Kroah-Hartman --- net/batman-adv/network-coding.c | 33 +++++++++++++++------------------ 1 file changed, 15 insertions(+), 18 deletions(-) --- a/net/batman-adv/network-coding.c +++ b/net/batman-adv/network-coding.c @@ -828,19 +828,29 @@ static struct batadv_nc_node spinlock_t *lock; /* Used to lock list selected by "int in_coding" */ struct list_head *list; + /* Select ingoing or outgoing coding node */ + if (in_coding) { + lock = &orig_neigh_node->in_coding_list_lock; + list = &orig_neigh_node->in_coding_list; + } else { + lock = &orig_neigh_node->out_coding_list_lock; + list = &orig_neigh_node->out_coding_list; + } + + spin_lock_bh(lock); + /* Check if nc_node is already added */ nc_node = batadv_nc_find_nc_node(orig_node, orig_neigh_node, in_coding); /* Node found */ if (nc_node) - return nc_node; + goto unlock; nc_node = kzalloc(sizeof(*nc_node), GFP_ATOMIC); if (!nc_node) - return NULL; + goto unlock; - if (!atomic_inc_not_zero(&orig_neigh_node->refcount)) - goto free; + atomic_inc(&orig_neigh_node->refcount); /* Initialize nc_node */ INIT_LIST_HEAD(&nc_node->list); @@ -848,28 +858,15 @@ static struct batadv_nc_node nc_node->orig_node = orig_neigh_node; atomic_set(&nc_node->refcount, 2); - /* Select ingoing or outgoing coding node */ - if (in_coding) { - lock = &orig_neigh_node->in_coding_list_lock; - list = &orig_neigh_node->in_coding_list; - } else { - lock = &orig_neigh_node->out_coding_list_lock; - list = &orig_neigh_node->out_coding_list; - } - batadv_dbg(BATADV_DBG_NC, bat_priv, "Adding nc_node %pM -> %pM\n", nc_node->addr, nc_node->orig_node->orig); /* Add nc_node to orig_node */ - spin_lock_bh(lock); list_add_tail_rcu(&nc_node->list, list); +unlock: spin_unlock_bh(lock); return nc_node; - -free: - kfree(nc_node); - return NULL; } /**