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=-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 B01EAC4332B for ; Thu, 19 Mar 2020 13:09:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7A7AD208D6 for ; Thu, 19 Mar 2020 13:09:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584623370; bh=afazES3LJUgiIS1Fm0X0rEFWfns6OqumedveuowKv8Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=YShnj2PxEBgvHmadLlJFWSQcw9VWUy2FNoNPQawYp5Gdw3vDs/4SBDZf55/W/XXwk yQ1AJR1Sqte5jtyyi+ssS1Sq7qzPfPtnOW5JRtqBqNLo2r6LsoMEEo7EKHS8/Aa8Cr w+ckKQ+AIyT17thUYR3sXC1MnEQrTN/7JNpIb1rc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728346AbgCSNJ3 (ORCPT ); Thu, 19 Mar 2020 09:09:29 -0400 Received: from mail.kernel.org ([198.145.29.99]:53928 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728331AbgCSNJ1 (ORCPT ); Thu, 19 Mar 2020 09:09:27 -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 42C1820789; Thu, 19 Mar 2020 13:09:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584623366; bh=afazES3LJUgiIS1Fm0X0rEFWfns6OqumedveuowKv8Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Ys0XafyJ5AFEKHg4YTImEwUdB9IvEzhZ5PD88aGeHVdWwwTAqJO7rgDXjIpDx4upc Fy/x+n0iGOQfbar3lcFgEP3ILbN/CFLzLjKOX51NDS6pVYAJYHoG+oscWIw0pN+L60 EFhYBoqT2fg9wk4t4Nj439em34C/Wmlsl8wVBeW0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , Sven Eckelmann , Simon Wunderlich Subject: [PATCH 4.4 79/93] batman-adv: Prevent duplicated tvlv handler Date: Thu, 19 Mar 2020 14:00:23 +0100 Message-Id: <20200319123949.663710173@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 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sven Eckelmann commit ae3cdc97dc10c7a3b31f297dab429bfb774c9ccb upstream. 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: Greg Kroah-Hartman --- net/batman-adv/main.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/net/batman-adv/main.c +++ b/net/batman-adv/main.c @@ -1079,15 +1079,20 @@ void batadv_tvlv_handler_register(struct { 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_free_ref(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; @@ -1097,7 +1102,6 @@ void batadv_tvlv_handler_register(struct atomic_set(&tvlv_handler->refcount, 1); INIT_HLIST_NODE(&tvlv_handler->list); - spin_lock_bh(&bat_priv->tvlv.handler_list_lock); hlist_add_head_rcu(&tvlv_handler->list, &bat_priv->tvlv.handler_list); spin_unlock_bh(&bat_priv->tvlv.handler_list_lock); }