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,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 21753C65C20 for ; Mon, 8 Oct 2018 15:26:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DAF942152C for ; Mon, 8 Oct 2018 15:26:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="pyEqRyTq" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DAF942152C 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 S1728342AbeJHWix (ORCPT ); Mon, 8 Oct 2018 18:38:53 -0400 Received: from mail.kernel.org ([198.145.29.99]:57588 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728321AbeJHWiw (ORCPT ); Mon, 8 Oct 2018 18:38:52 -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 2BEBC214FF; Mon, 8 Oct 2018 15:26:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1539012396; bh=7wr5E5C/Ls5l9ZH+bf5LjcvGZ0NXpMrOUbpTwd2kfZE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pyEqRyTqksibG+toiyDNCvlgV/6o0IGeA/xi/I9M26rNLfAQW5knUKOYYSMGBTm9N 7AUupNinRRRykDi96SqYp3rKEaTEokDhLGVLws22oGi8nC915RbdBfXGWTqEi8teAb TYXia3fIPZYtJpyeyMT3tFnXiI39DcUNWcDhpSKY= 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 06/32] batman-adv: Prevent duplicated nc_node entry Date: Mon, 8 Oct 2018 11:26:03 -0400 Message-Id: <20181008152629.70812-6-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 fa122fec8640eb7186ce5a41b83a4c1744ceef8f ] 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: Sasha Levin --- net/batman-adv/network-coding.c | 27 +++++++++++++++------------ 1 file changed, 15 insertions(+), 12 deletions(-) diff --git a/net/batman-adv/network-coding.c b/net/batman-adv/network-coding.c index 3604d7899e2c..7a7dcac20566 100644 --- a/net/batman-adv/network-coding.c +++ b/net/batman-adv/network-coding.c @@ -850,16 +850,27 @@ batadv_nc_get_nc_node(struct batadv_priv *bat_priv, 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; /* Initialize nc_node */ INIT_LIST_HEAD(&nc_node->list); @@ -868,22 +879,14 @@ batadv_nc_get_nc_node(struct batadv_priv *bat_priv, kref_get(&orig_neigh_node->refcount); nc_node->orig_node = orig_neigh_node; - /* 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); kref_get(&nc_node->refcount); list_add_tail_rcu(&nc_node->list, list); + +unlock: spin_unlock_bh(lock); return nc_node; -- 2.17.1