[linux-next] LinuxNextTracking branch, master, updated. next-20180921

batman at open-mesh.org batman at open-mesh.org
Sat Sep 22 00:20:38 CEST 2018


The following commit has been merged in the master branch:
commit e7136e48ffdfb9f37b0820f619380485eb407361
Author: Sven Eckelmann <sven at narfation.org>
Date:   Sun Aug 12 21:04:44 2018 +0200

    batman-adv: Prevent duplicated global TT entry
    
    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 at narfation.org>
    Signed-off-by: Simon Wunderlich <sw at simonwunderlich.de>

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 @@ sync_flags:
 out:
 	if (orig_entry)
 		batadv_tt_orig_list_entry_put(orig_entry);
+
+	spin_unlock_bh(&tt_global->list_lock);
 }
 
 /**

-- 
LinuxNextTracking


More information about the linux-merge mailing list