From mboxrd@z Thu Jan 1 00:00:00 1970 From: Simon Wunderlich Subject: [PATCH 07/11] batman-adv: Prevent duplicated global TT entry Date: Wed, 19 Sep 2018 14:22:09 +0200 Message-ID: <20180919122213.23108-8-sw@simonwunderlich.de> References: <20180919122213.23108-1-sw@simonwunderlich.de> Reply-To: The list for a Better Approach To Mobile Ad-hoc Networking Cc: netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, b.a.t.m.a.n-ZwoEplunGu2X36UT3dwllkB+6BGkLq7r@public.gmane.org To: davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org Return-path: In-Reply-To: <20180919122213.23108-1-sw-2YrNx6rUIHYiY0qSoAWiAoQuADTiUCJX@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: b.a.t.m.a.n-bounces-ZwoEplunGu2X36UT3dwllkB+6BGkLq7r@public.gmane.org Sender: "B.A.T.M.A.N" List-Id: netdev.vger.kernel.org From: Sven Eckelmann The function batadv_tt_global_orig_entry_add is responsible for adding new tt_orig_list_entry to the orig_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: d657e621a0f5 ("batman-adv: add reference counting for type batadv_tt_orig_list_entry") Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich --- net/batman-adv/translation-table.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c index 12a2b7d21376..d21624c44665 100644 --- a/net/batman-adv/translation-table.c +++ b/net/batman-adv/translation-table.c @@ -1613,6 +1613,8 @@ batadv_tt_global_orig_entry_add(struct batadv_tt_global_entry *tt_global, { struct batadv_tt_orig_list_entry *orig_entry; + spin_lock_bh(&tt_global->list_lock); + orig_entry = batadv_tt_global_orig_entry_find(tt_global, orig_node); if (orig_entry) { /* refresh the ttvn: the current value could be a bogus one that @@ -1635,11 +1637,9 @@ batadv_tt_global_orig_entry_add(struct batadv_tt_global_entry *tt_global, orig_entry->flags = flags; kref_init(&orig_entry->refcount); - spin_lock_bh(&tt_global->list_lock); kref_get(&orig_entry->refcount); hlist_add_head_rcu(&orig_entry->list, &tt_global->orig_list); - spin_unlock_bh(&tt_global->list_lock); atomic_inc(&tt_global->orig_list_count); sync_flags: @@ -1647,6 +1647,8 @@ batadv_tt_global_orig_entry_add(struct batadv_tt_global_entry *tt_global, out: if (orig_entry) batadv_tt_orig_list_entry_put(orig_entry); + + spin_unlock_bh(&tt_global->list_lock); } /** -- 2.11.0