batman-adv: fix indirect hard_iface NULL dereference

[ Upstream commit 16a4142363b11952d3aa76ac78004502c0c2fe6e ]

If hard_iface is NULL and goto out is made batadv_hardif_free_ref()
doesn't check for NULL before dereferencing it to get to refcount.

Introduced in cb1c92ec37fb70543d133a1fa7d9b54d6f8a1ecd
("batman-adv: add debugfs support to view multiif tables").

Reported-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Acked-by: Antonio Quartulli <antonio@meshcoding.com>
Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/batman-adv/originator.c b/net/batman-adv/originator.c
index 3e6dd91..abf612d 100644 (file)
--- a/net/batman-adv/originator.c
+++ b/net/batman-adv/originator.c
@@ -1074,7 +1074,8 @@ int batadv_orig_hardif_seq_print_text(struct seq_file *seq, void *offset)
        bat_priv->bat_algo_ops->bat_orig_print(bat_priv, seq, hard_iface);
 
 out:
-       batadv_hardif_free_ref(hard_iface);
+       if (hard_iface)
+               batadv_hardif_free_ref(hard_iface);
        return 0;
 }