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 931F6C677E4 for ; Mon, 8 Oct 2018 15:27:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5ADED2156F for ; Mon, 8 Oct 2018 15:27:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="mNdvcd7E" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5ADED2156F 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 S1728844AbeJHWj2 (ORCPT ); Mon, 8 Oct 2018 18:39:28 -0400 Received: from mail.kernel.org ([198.145.29.99]:58642 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728820AbeJHWj1 (ORCPT ); Mon, 8 Oct 2018 18:39:27 -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 5C3592154C; Mon, 8 Oct 2018 15:27:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1539012431; bh=/MB0G4n9wNs8d3nIvdPCEQU71Wjr6f7TELeoXCLveUQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mNdvcd7EteGpiEzrVFYkeYpFQ64apsFgnvJlea1hsN/FTo+xK3Gqc5RytiFKrHTtk bWxVb/gJ1fW1FK2a7NW1FiawRLcYfUbJ+t/x6vDvMV+CeP3o4NTpDp1/khuS7p292g ZVdfyNzDbbtlyyYTCE26iaI+GCfk1OfJtbURKt7E= From: Sasha Levin To: stable@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Sven Eckelmann , Simon Wunderlich , Sasha Levin Subject: [PATCH AUTOSEL 4.9 07/23] batman-adv: Prevent duplicated tvlv handler Date: Mon, 8 Oct 2018 11:26:47 -0400 Message-Id: <20181008152703.70891-7-sashal@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20181008152703.70891-1-sashal@kernel.org> References: <20181008152703.70891-1-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 ae3cdc97dc10c7a3b31f297dab429bfb774c9ccb ] The function batadv_tvlv_handler_register is responsible for adding new tvlv_handler to the handler_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: ef26157747d4 ("batman-adv: tvlv - basic infrastructure") Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich Signed-off-by: Sasha Levin --- net/batman-adv/tvlv.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/net/batman-adv/tvlv.c b/net/batman-adv/tvlv.c index 77654f055f24..8e91a26e9b00 100644 --- a/net/batman-adv/tvlv.c +++ b/net/batman-adv/tvlv.c @@ -528,15 +528,20 @@ void batadv_tvlv_handler_register(struct batadv_priv *bat_priv, { struct batadv_tvlv_handler *tvlv_handler; + spin_lock_bh(&bat_priv->tvlv.handler_list_lock); + tvlv_handler = batadv_tvlv_handler_get(bat_priv, type, version); if (tvlv_handler) { + spin_unlock_bh(&bat_priv->tvlv.handler_list_lock); batadv_tvlv_handler_put(tvlv_handler); return; } tvlv_handler = kzalloc(sizeof(*tvlv_handler), GFP_ATOMIC); - if (!tvlv_handler) + if (!tvlv_handler) { + spin_unlock_bh(&bat_priv->tvlv.handler_list_lock); return; + } tvlv_handler->ogm_handler = optr; tvlv_handler->unicast_handler = uptr; @@ -546,7 +551,6 @@ void batadv_tvlv_handler_register(struct batadv_priv *bat_priv, kref_init(&tvlv_handler->refcount); INIT_HLIST_NODE(&tvlv_handler->list); - spin_lock_bh(&bat_priv->tvlv.handler_list_lock); kref_get(&tvlv_handler->refcount); hlist_add_head_rcu(&tvlv_handler->list, &bat_priv->tvlv.handler_list); spin_unlock_bh(&bat_priv->tvlv.handler_list_lock); -- 2.17.1