From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:42892 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754683AbbJRCbY (ORCPT ); Sat, 17 Oct 2015 22:31:24 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, alfonsname@web.de, Marek Lindner , Antonio Quartulli Subject: [PATCH 4.1 126/202] batman-adv: protect tt_local_entry from concurrent delete events Date: Sat, 17 Oct 2015 18:58:29 -0700 Message-Id: <20151018014907.653410874@linuxfoundation.org> In-Reply-To: <20151018014901.946875729@linuxfoundation.org> References: <20151018014901.946875729@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: stable-owner@vger.kernel.org List-ID: 4.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Marek Lindner commit ef72706a0543d0c3a5ab29bd6378fdfb368118d9 upstream. The tt_local_entry deletion performed in batadv_tt_local_remove() was neither protecting against simultaneous deletes nor checking whether the element was still part of the list before calling hlist_del_rcu(). Replacing the hlist_del_rcu() call with batadv_hash_remove() provides adequate protection via hash spinlocks as well as an is-element-still-in-hash check to avoid 'blind' hash removal. Fixes: 068ee6e204e1 ("batman-adv: roaming handling mechanism redesign") Reported-by: alfonsname@web.de Signed-off-by: Marek Lindner Signed-off-by: Antonio Quartulli Signed-off-by: Greg Kroah-Hartman --- net/batman-adv/translation-table.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) --- a/net/batman-adv/translation-table.c +++ b/net/batman-adv/translation-table.c @@ -1018,6 +1018,7 @@ uint16_t batadv_tt_local_remove(struct b struct batadv_tt_local_entry *tt_local_entry; uint16_t flags, curr_flags = BATADV_NO_FLAGS; struct batadv_softif_vlan *vlan; + void *tt_entry_exists; tt_local_entry = batadv_tt_local_hash_find(bat_priv, addr, vid); if (!tt_local_entry) @@ -1045,7 +1046,15 @@ uint16_t batadv_tt_local_remove(struct b * immediately purge it */ batadv_tt_local_event(bat_priv, tt_local_entry, BATADV_TT_CLIENT_DEL); - hlist_del_rcu(&tt_local_entry->common.hash_entry); + + tt_entry_exists = batadv_hash_remove(bat_priv->tt.local_hash, + batadv_compare_tt, + batadv_choose_tt, + &tt_local_entry->common); + if (!tt_entry_exists) + goto out; + + /* extra call to free the local tt entry */ batadv_tt_local_entry_free_ref(tt_local_entry); /* decrease the reference held for this vlan */