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 D316DC4332B for ; Thu, 19 Mar 2020 13:37:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9772220789 for ; Thu, 19 Mar 2020 13:37:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584625054; bh=BzyWt1yyJqFGlxsed1AfS2TSjeJTUbCBPz4Zprclf18=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=PVeFOS+W0YUPE4b0laq9AVMFO+ICd4U0J6oKP5jWwvk3CKlCs8xlRjP2LzPH0VfDA +YjFncHYxne+uI6q2JwXvBYv72mk5vK1y+aXYlXnPcRcAxmYzWfDzD6gAWvjBQbl3x Bh5lRE+haID/ygKVT88w9lD9t4AYSLpygySZkKB4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728107AbgCSNIO (ORCPT ); Thu, 19 Mar 2020 09:08:14 -0400 Received: from mail.kernel.org ([198.145.29.99]:52360 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727486AbgCSNIO (ORCPT ); Thu, 19 Mar 2020 09:08:14 -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 DA7BE208FE; Thu, 19 Mar 2020 13:08:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584623293; bh=BzyWt1yyJqFGlxsed1AfS2TSjeJTUbCBPz4Zprclf18=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0NJuTndmjYKo/Wm1hZb6wvGcxI2Vjmybjin0lvGnW1rk4x/5QSvTdQu6FNn1FJJWt PYCfModfX8mUZF4Kz67KamNaOOdHjjb/gn1bMi6uxm6zPJbbEEo4S19EM/43La8Ws6 IK9YiSBh4QaEKYQ15mHKVK/9kq5HfNYMKBdwysQ8= 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 57/93] batman-adv: Fix non-atomic bla_claim::backbone_gw access Date: Thu, 19 Mar 2020 14:00:01 +0100 Message-Id: <20200319123943.003265441@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: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Sven Eckelmann commit 3db0decf1185357d6ab2256d0dede1ca9efda03d upstream. The pointer batadv_bla_claim::backbone_gw can be changed at any time. Therefore, access to it must be protected to ensure that two function accessing the same backbone_gw are actually accessing the same. This is especially important when the crc_lock is used or when the backbone_gw of a claim is exchanged. Not doing so leads to invalid memory access and/or reference leaks. Fixes: 23721387c409 ("batman-adv: add basic bridge loop avoidance code") Fixes: 5a1dd8a4773d ("batman-adv: lock crc access in bridge loop avoidance") Signed-off-by: Sven Eckelmann Signed-off-by: Marek Lindner Signed-off-by: Simon Wunderlich Signed-off-by: Greg Kroah-Hartman --- net/batman-adv/bridge_loop_avoidance.c | 112 ++++++++++++++++++++++++++------- net/batman-adv/types.h | 1 2 files changed, 90 insertions(+), 23 deletions(-) --- a/net/batman-adv/bridge_loop_avoidance.c +++ b/net/batman-adv/bridge_loop_avoidance.c @@ -129,7 +129,19 @@ batadv_backbone_gw_free_ref(struct batad /* finally deinitialize the claim */ static void batadv_claim_release(struct batadv_bla_claim *claim) { - batadv_backbone_gw_free_ref(claim->backbone_gw); + struct batadv_bla_backbone_gw *old_backbone_gw; + + spin_lock_bh(&claim->backbone_lock); + old_backbone_gw = claim->backbone_gw; + claim->backbone_gw = NULL; + spin_unlock_bh(&claim->backbone_lock); + + spin_lock_bh(&old_backbone_gw->crc_lock); + old_backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN); + spin_unlock_bh(&old_backbone_gw->crc_lock); + + batadv_backbone_gw_free_ref(old_backbone_gw); + kfree_rcu(claim, rcu); } @@ -579,8 +591,10 @@ static void batadv_bla_add_claim(struct const u8 *mac, const unsigned short vid, struct batadv_bla_backbone_gw *backbone_gw) { + struct batadv_bla_backbone_gw *old_backbone_gw; struct batadv_bla_claim *claim; struct batadv_bla_claim search_claim; + bool remove_crc = false; int hash_added; ether_addr_copy(search_claim.addr, mac); @@ -594,8 +608,10 @@ static void batadv_bla_add_claim(struct return; ether_addr_copy(claim->addr, mac); + spin_lock_init(&claim->backbone_lock); claim->vid = vid; claim->lasttime = jiffies; + atomic_inc(&backbone_gw->refcount); claim->backbone_gw = backbone_gw; atomic_set(&claim->refcount, 2); @@ -622,15 +638,26 @@ static void batadv_bla_add_claim(struct "bla_add_claim(): changing ownership for %pM, vid %d\n", mac, BATADV_PRINT_VID(vid)); - spin_lock_bh(&claim->backbone_gw->crc_lock); - claim->backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN); - spin_unlock_bh(&claim->backbone_gw->crc_lock); - batadv_backbone_gw_free_ref(claim->backbone_gw); + remove_crc = true; } - /* set (new) backbone gw */ + + /* replace backbone_gw atomically and adjust reference counters */ + spin_lock_bh(&claim->backbone_lock); + old_backbone_gw = claim->backbone_gw; atomic_inc(&backbone_gw->refcount); claim->backbone_gw = backbone_gw; + spin_unlock_bh(&claim->backbone_lock); + if (remove_crc) { + /* remove claim address from old backbone_gw */ + spin_lock_bh(&old_backbone_gw->crc_lock); + old_backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN); + spin_unlock_bh(&old_backbone_gw->crc_lock); + } + + batadv_backbone_gw_free_ref(old_backbone_gw); + + /* add claim address to new backbone_gw */ spin_lock_bh(&backbone_gw->crc_lock); backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN); spin_unlock_bh(&backbone_gw->crc_lock); @@ -640,6 +667,26 @@ claim_free_ref: batadv_claim_free_ref(claim); } +/** + * batadv_bla_claim_get_backbone_gw - Get valid reference for backbone_gw of + * claim + * @claim: claim whose backbone_gw should be returned + * + * Return: valid reference to claim::backbone_gw + */ +static struct batadv_bla_backbone_gw * +batadv_bla_claim_get_backbone_gw(struct batadv_bla_claim *claim) +{ + struct batadv_bla_backbone_gw *backbone_gw; + + spin_lock_bh(&claim->backbone_lock); + backbone_gw = claim->backbone_gw; + atomic_inc(&backbone_gw->refcount); + spin_unlock_bh(&claim->backbone_lock); + + return backbone_gw; +} + /* Delete a claim from the claim hash which has the * given mac address and vid. */ @@ -661,10 +708,6 @@ static void batadv_bla_del_claim(struct batadv_choose_claim, claim); batadv_claim_free_ref(claim); /* reference from the hash is gone */ - spin_lock_bh(&claim->backbone_gw->crc_lock); - claim->backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN); - spin_unlock_bh(&claim->backbone_gw->crc_lock); - /* don't need the reference from hash_find() anymore */ batadv_claim_free_ref(claim); } @@ -1074,6 +1117,7 @@ static void batadv_bla_purge_claims(stru struct batadv_hard_iface *primary_if, int now) { + struct batadv_bla_backbone_gw *backbone_gw; struct batadv_bla_claim *claim; struct hlist_head *head; struct batadv_hashtable *hash; @@ -1088,14 +1132,17 @@ static void batadv_bla_purge_claims(stru rcu_read_lock(); hlist_for_each_entry_rcu(claim, head, hash_entry) { + backbone_gw = batadv_bla_claim_get_backbone_gw(claim); if (now) goto purge_now; - if (!batadv_compare_eth(claim->backbone_gw->orig, + + if (!batadv_compare_eth(backbone_gw->orig, primary_if->net_dev->dev_addr)) - continue; + goto skip; + if (!batadv_has_timed_out(claim->lasttime, BATADV_BLA_CLAIM_TIMEOUT)) - continue; + goto skip; batadv_dbg(BATADV_DBG_BLA, bat_priv, "bla_purge_claims(): %pM, vid %d, time out\n", @@ -1103,8 +1150,10 @@ static void batadv_bla_purge_claims(stru purge_now: batadv_handle_unclaim(bat_priv, primary_if, - claim->backbone_gw->orig, + backbone_gw->orig, claim->addr, claim->vid); +skip: + batadv_backbone_gw_free_ref(backbone_gw); } rcu_read_unlock(); } @@ -1488,9 +1537,11 @@ void batadv_bla_free(struct batadv_priv int batadv_bla_rx(struct batadv_priv *bat_priv, struct sk_buff *skb, unsigned short vid, bool is_bcast) { + struct batadv_bla_backbone_gw *backbone_gw; struct ethhdr *ethhdr; struct batadv_bla_claim search_claim, *claim = NULL; struct batadv_hard_iface *primary_if; + bool own_claim; int ret; ethhdr = eth_hdr(skb); @@ -1522,8 +1573,12 @@ int batadv_bla_rx(struct batadv_priv *ba } /* if it is our own claim ... */ - if (batadv_compare_eth(claim->backbone_gw->orig, - primary_if->net_dev->dev_addr)) { + backbone_gw = batadv_bla_claim_get_backbone_gw(claim); + own_claim = batadv_compare_eth(backbone_gw->orig, + primary_if->net_dev->dev_addr); + batadv_backbone_gw_free_ref(backbone_gw); + + if (own_claim) { /* ... allow it in any case */ claim->lasttime = jiffies; goto allow; @@ -1586,7 +1641,9 @@ int batadv_bla_tx(struct batadv_priv *ba { struct ethhdr *ethhdr; struct batadv_bla_claim search_claim, *claim = NULL; + struct batadv_bla_backbone_gw *backbone_gw; struct batadv_hard_iface *primary_if; + bool client_roamed; int ret = 0; primary_if = batadv_primary_if_get_selected(bat_priv); @@ -1616,8 +1673,12 @@ int batadv_bla_tx(struct batadv_priv *ba goto allow; /* check if we are responsible. */ - if (batadv_compare_eth(claim->backbone_gw->orig, - primary_if->net_dev->dev_addr)) { + backbone_gw = batadv_bla_claim_get_backbone_gw(claim); + client_roamed = batadv_compare_eth(backbone_gw->orig, + primary_if->net_dev->dev_addr); + batadv_backbone_gw_free_ref(backbone_gw); + + if (client_roamed) { /* if yes, the client has roamed and we have * to unclaim it. */ @@ -1670,6 +1731,7 @@ int batadv_bla_claim_table_seq_print_tex struct net_device *net_dev = (struct net_device *)seq->private; struct batadv_priv *bat_priv = netdev_priv(net_dev); struct batadv_hashtable *hash = bat_priv->bla.claim_hash; + struct batadv_bla_backbone_gw *backbone_gw; struct batadv_bla_claim *claim; struct batadv_hard_iface *primary_if; struct hlist_head *head; @@ -1694,17 +1756,21 @@ int batadv_bla_claim_table_seq_print_tex rcu_read_lock(); hlist_for_each_entry_rcu(claim, head, hash_entry) { - is_own = batadv_compare_eth(claim->backbone_gw->orig, + backbone_gw = batadv_bla_claim_get_backbone_gw(claim); + + is_own = batadv_compare_eth(backbone_gw->orig, primary_addr); - spin_lock_bh(&claim->backbone_gw->crc_lock); - backbone_crc = claim->backbone_gw->crc; - spin_unlock_bh(&claim->backbone_gw->crc_lock); + spin_lock_bh(&backbone_gw->crc_lock); + backbone_crc = backbone_gw->crc; + spin_unlock_bh(&backbone_gw->crc_lock); seq_printf(seq, " * %pM on %5d by %pM [%c] (%#.4x)\n", claim->addr, BATADV_PRINT_VID(claim->vid), - claim->backbone_gw->orig, + backbone_gw->orig, (is_own ? 'x' : ' '), backbone_crc); + + batadv_backbone_gw_free_ref(backbone_gw); } rcu_read_unlock(); } --- a/net/batman-adv/types.h +++ b/net/batman-adv/types.h @@ -917,6 +917,7 @@ struct batadv_bla_claim { u8 addr[ETH_ALEN]; unsigned short vid; struct batadv_bla_backbone_gw *backbone_gw; + spinlock_t backbone_lock; /* protects backbone_gw */ unsigned long lasttime; struct hlist_node hash_entry; struct rcu_head rcu;