diff mbox series

[07/11] batman-adv: Prevent duplicated global TT entry

Message ID	20180919122213.23108-8-sw@simonwunderlich.de (mailing list archive)
State	Not Applicable, archived
Delegated to:	Simon Wunderlich
Headers	Received-SPF: Pass (mailfrom) identity=mailfrom; client-ip=2001:4d88:2000:24::c0de; helo=mail.mail.packetmixer.de; envelope-from=sw@simonwunderlich.de; receiver=<UNKNOWN> From: Simon Wunderlich <sw@simonwunderlich.de> To: davem@davemloft.net Date: Wed, 19 Sep 2018 14:22:09 +0200 Message-Id: <20180919122213.23108-8-sw@simonwunderlich.de> In-Reply-To: <20180919122213.23108-1-sw@simonwunderlich.de> References: <20180919122213.23108-1-sw@simonwunderlich.de> Subject: [B.A.T.M.A.N.] [PATCH 07/11] batman-adv: Prevent duplicated global TT entry Precedence: list Reply-To: The list for a Better Approach To Mobile Ad-hoc Networking <b.a.t.m.a.n@lists.open-mesh.org> Cc: netdev@vger.kernel.org, b.a.t.m.a.n@lists.open-mesh.org Errors-To: b.a.t.m.a.n-bounces@lists.open-mesh.org Sender: "B.A.T.M.A.N" <b.a.t.m.a.n-bounces@lists.open-mesh.org>
Series	[01/11] batman-adv: Avoid probe ELP information leak \| [01/11] batman-adv: Avoid probe ELP information leak [02/11] batman-adv: Fix segfault when writing to throughput_override [03/11] batman-adv: Fix segfault when writing to sysfs elp_interval [04/11] batman-adv: Prevent duplicated gateway_node entry [05/11] batman-adv: Prevent duplicated nc_node entry [06/11] batman-adv: Prevent duplicated softif_vlan entry [07/11] batman-adv: Prevent duplicated global TT entry [08/11] batman-adv: Prevent duplicated tvlv handler [09/11] batman-adv: fix backbone_gw refcount on queue_work() failure [10/11] batman-adv: fix hardif_neigh refcount on queue_work() failure [11/11] batman-adv: Increase version number to 2018.3

Commit Message

Simon Wunderlich Sept. 19, 2018, 12:22 p.m. UTC

  From: Sven Eckelmann <sven@narfation.org>

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 <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
---
 net/batman-adv/translation-table.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff mbox series

Patch

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);
 }
 
 /**