netdev - [PATCH 12/17] batman-adv: Less function calls in batadv_is_ap

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20161027190150.7880-13-sw@simonwunderlich.de>
Date:   Thu, 27 Oct 2016 21:01:45 +0200
From:   Simon Wunderlich <sw@...onwunderlich.de>
To:     davem@...emloft.net
Cc:     netdev@...r.kernel.org, b.a.t.m.a.n@...ts.open-mesh.org,
        Markus Elfring <elfring@...rs.sourceforge.net>,
        Sven Eckelmann <sven@...fation.org>,
        Simon Wunderlich <sw@...onwunderlich.de>
Subject: [PATCH 12/17] batman-adv: Less function calls in batadv_is_ap_isolated() after error detection

From: Markus Elfring <elfring@...rs.sourceforge.net>

The variables "tt_local_entry" and "tt_global_entry" were eventually
checked again despite of a corresponding null pointer test before.

* Avoid this double check by reordering a function call sequence
  and the better selection of jump targets.

* Omit the initialisation for these variables at the beginning then.

Signed-off-by: Markus Elfring <elfring@...rs.sourceforge.net>
Signed-off-by: Sven Eckelmann <sven@...fation.org>
Signed-off-by: Simon Wunderlich <sw@...onwunderlich.de>
---
 net/batman-adv/translation-table.c | 25 +++++++++++--------------
 1 file changed, 11 insertions(+), 14 deletions(-)

diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c
index 7f66309..ad1e3bc 100644
--- a/net/batman-adv/translation-table.c
+++ b/net/batman-adv/translation-table.c
@@ -3835,8 +3835,8 @@ void batadv_tt_local_commit_changes(struct batadv_priv *bat_priv)
 bool batadv_is_ap_isolated(struct batadv_priv *bat_priv, u8 *src, u8 *dst,
 			   unsigned short vid)
 {
-	struct batadv_tt_local_entry *tt_local_entry = NULL;
-	struct batadv_tt_global_entry *tt_global_entry = NULL;
+	struct batadv_tt_local_entry *tt_local_entry;
+	struct batadv_tt_global_entry *tt_global_entry;
 	struct batadv_softif_vlan *vlan;
 	bool ret = false;
 
@@ -3845,27 +3845,24 @@ bool batadv_is_ap_isolated(struct batadv_priv *bat_priv, u8 *src, u8 *dst,
 		return false;
 
 	if (!atomic_read(&vlan->ap_isolation))
-		goto out;
+		goto vlan_put;
 
 	tt_local_entry = batadv_tt_local_hash_find(bat_priv, dst, vid);
 	if (!tt_local_entry)
-		goto out;
+		goto vlan_put;
 
 	tt_global_entry = batadv_tt_global_hash_find(bat_priv, src, vid);
 	if (!tt_global_entry)
-		goto out;
-
-	if (!_batadv_is_ap_isolated(tt_local_entry, tt_global_entry))
-		goto out;
+		goto local_entry_put;
 
-	ret = true;
+	if (_batadv_is_ap_isolated(tt_local_entry, tt_global_entry))
+		ret = true;
 
-out:
+	batadv_tt_global_entry_put(tt_global_entry);
+local_entry_put:
+	batadv_tt_local_entry_put(tt_local_entry);
+vlan_put:
 	batadv_softif_vlan_put(vlan);
-	if (tt_global_entry)
-		batadv_tt_global_entry_put(tt_global_entry);
-	if (tt_local_entry)
-		batadv_tt_local_entry_put(tt_local_entry);
 	return ret;
 }
 
-- 
2.10.1