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authorSven Eckelmann <sven@narfation.org>2020-03-18 00:27:27 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-03-20 09:06:31 +0100
commit8b274cf520a477e7a43611328452f48d0abbf40a (patch)
tree02cfd72ba6d645a3b0a441001a6deebec13b4991
parent25cc58696f5796a7f250b27b150b42e362a19fb0 (diff)
batman-adv: Prevent duplicated global TT entry
commit e7136e48ffdfb9f37b0820f619380485eb407361 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--net/batman-adv/translation-table.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c
index 4a685cf2439d..1d445293efea 100644
--- a/net/batman-adv/translation-table.c
+++ b/net/batman-adv/translation-table.c
@@ -1315,6 +1315,8 @@ 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
@@ -1337,10 +1339,8 @@ batadv_tt_global_orig_entry_add(struct batadv_tt_global_entry *tt_global,
orig_entry->flags = flags;
atomic_set(&orig_entry->refcount, 2);
- spin_lock_bh(&tt_global->list_lock);
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:
@@ -1348,6 +1348,8 @@ sync_flags:
out:
if (orig_entry)
batadv_tt_orig_list_entry_free_ref(orig_entry);
+
+ spin_unlock_bh(&tt_global->list_lock);
}
/**