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 DC2D4C4332E for ; Thu, 19 Mar 2020 13:33:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B326120409 for ; Thu, 19 Mar 2020 13:33:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584624827; bh=VuE7TmDy3e1X1Gvxz8ud/ys5uK9G3jifL4rHLjlRcJQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Qg1qAoDiQS+vEAhHIDwFPKnhr4C1d5nebuiUyWYGk8m6tKrFMbgEyaX1YlB9OrI44 VC5zh/j2Tam0ZxZm5FDI/T8Vi46wJsqcI9/RZB1v9r3DrE07+bx+VzXBUkHYtrF2Zq n008bby+sJYA0GXAC1HQwUOFOB5f5tamLMqwDTsg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727789AbgCSNdq (ORCPT ); Thu, 19 Mar 2020 09:33:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:60260 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729140AbgCSNNR (ORCPT ); Thu, 19 Mar 2020 09:13:17 -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 1183620722; Thu, 19 Mar 2020 13:13:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584623596; bh=VuE7TmDy3e1X1Gvxz8ud/ys5uK9G3jifL4rHLjlRcJQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AuXx42nlDCq/aTAnczf1oOwUOBToZA0kBwftG0zWXz6EPzpBA0CUZYwzoL9YvojRN mO5BraZ0/TXJPcinfBfSXUmGtGh1JrBGJGbatbSGWKKfh1HC0T0h6e89HBfopdZjLN gR9Obe+KYAemLVKVk7xvpdButVRD2WgE5OAJU7tA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , Sven Eckelmann , Antonio Quartulli , Simon Wunderlich Subject: [PATCH 4.9 63/90] batman-adv: Avoid race in TT TVLV allocator helper Date: Thu, 19 Mar 2020 14:00:25 +0100 Message-Id: <20200319123948.071644105@linuxfoundation.org> X-Mailer: git-send-email 2.25.2 In-Reply-To: <20200319123928.635114118@linuxfoundation.org> References: <20200319123928.635114118@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 8ba0f9bd3bdea1058c2b2676bec7905724418e40 upstream. The functions batadv_tt_prepare_tvlv_local_data and batadv_tt_prepare_tvlv_global_data are responsible for preparing a buffer which can be used to store the TVLV container for TT and add the VLAN information to it. This will be done in three phases: 1. count the number of VLANs and their entries 2. allocate the buffer using the counters from the previous step and limits from the caller (parameter tt_len) 3. insert the VLAN information to the buffer The step 1 and 3 operate on a list which contains the VLANs. The access to these lists must be protected with an appropriate lock or otherwise they might operate on on different entries. This could for example happen when another context is adding VLAN entries to this list. This could lead to a buffer overflow in these functions when enough entries were added between step 1 and 3 to the VLAN lists that the buffer room for the entries (*tt_change) is smaller then the now required extra buffer for new VLAN entries. Fixes: 7ea7b4a14275 ("batman-adv: make the TT CRC logic VLAN specific") Signed-off-by: Sven Eckelmann Acked-by: Antonio Quartulli Signed-off-by: Simon Wunderlich Signed-off-by: Greg Kroah-Hartman --- net/batman-adv/translation-table.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) --- a/net/batman-adv/translation-table.c +++ b/net/batman-adv/translation-table.c @@ -867,7 +867,7 @@ batadv_tt_prepare_tvlv_global_data(struc struct batadv_orig_node_vlan *vlan; u8 *tt_change_ptr; - rcu_read_lock(); + spin_lock_bh(&orig_node->vlan_list_lock); hlist_for_each_entry_rcu(vlan, &orig_node->vlan_list, list) { num_vlan++; num_entries += atomic_read(&vlan->tt.num_entries); @@ -905,7 +905,7 @@ batadv_tt_prepare_tvlv_global_data(struc *tt_change = (struct batadv_tvlv_tt_change *)tt_change_ptr; out: - rcu_read_unlock(); + spin_unlock_bh(&orig_node->vlan_list_lock); return tvlv_len; } @@ -941,7 +941,7 @@ batadv_tt_prepare_tvlv_local_data(struct u8 *tt_change_ptr; int change_offset; - rcu_read_lock(); + spin_lock_bh(&bat_priv->softif_vlan_list_lock); hlist_for_each_entry_rcu(vlan, &bat_priv->softif_vlan_list, list) { num_vlan++; num_entries += atomic_read(&vlan->tt.num_entries); @@ -979,7 +979,7 @@ batadv_tt_prepare_tvlv_local_data(struct *tt_change = (struct batadv_tvlv_tt_change *)tt_change_ptr; out: - rcu_read_unlock(); + spin_unlock_bh(&bat_priv->softif_vlan_list_lock); return tvlv_len; }