batman-adv: Make bat_priv->primary_if an rcu protected pointer

The rcu protected macros rcu_dereference() and rcu_assign_pointer()
for the bat_priv->primary_if need to be used, as well as spin/rcu locking.

Otherwise we might end up using a primary_if pointer pointing to already
freed memory.

Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Signed-off-by: Sven Eckelmann <sven@narfation.org>

1 files changed, 43 insertions, 14 deletions

diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c
index 8d15b48d1692..f931830d630e 100644
--- a/net/batman-adv/translation-table.c
+++ b/net/batman-adv/translation-table.c
@@ -22,6 +22,7 @@
 #include "main.h"
 #include "translation-table.h"
 #include "soft-interface.h"
+#include "hard-interface.h"
 #include "hash.h"
 #include "originator.h"
 
@@ -237,16 +238,26 @@ int hna_local_seq_print_text(struct seq_file *seq, void *offset)
         struct bat_priv *bat_priv = netdev_priv(net_dev);
         struct hashtable_t *hash = bat_priv->hna_local_hash;
         struct hna_local_entry *hna_local_entry;
+        struct hard_iface *primary_if;
         struct hlist_node *node;
         struct hlist_head *head;
         size_t buf_size, pos;
         char *buff;
-        int i;
+        int i, ret = 0;
 
-        if (!bat_priv->primary_if) {
-                return seq_printf(seq, "BATMAN mesh %s disabled - "
-                               "please specify interfaces to enable it\n",
-                               net_dev->name);
+        primary_if = primary_if_get_selected(bat_priv);
+        if (!primary_if) {
+                ret = seq_printf(seq, "BATMAN mesh %s disabled - "
+                                 "please specify interfaces to enable it\n",
+                                 net_dev->name);
+                goto out;
+        }
+
+        if (primary_if->if_status != IF_ACTIVE) {
+                ret = seq_printf(seq, "BATMAN mesh %s disabled - "
+                                 "primary interface not active\n",
+                                 net_dev->name);
+                goto out;
         }
 
         seq_printf(seq, "Locally retrieved addresses (from %s) "
@@ -269,7 +280,8 @@ int hna_local_seq_print_text(struct seq_file *seq, void *offset)
         buff = kmalloc(buf_size, GFP_ATOMIC);
         if (!buff) {
                 spin_unlock_bh(&bat_priv->hna_lhash_lock);
-                return -ENOMEM;
+                ret = -ENOMEM;
+                goto out;
         }
 
         buff[0] = '\0';
@@ -291,7 +303,10 @@ int hna_local_seq_print_text(struct seq_file *seq, void *offset)
 
         seq_printf(seq, "%s", buff);
         kfree(buff);
-        return 0;
+out:
+        if (primary_if)
+                hardif_free_ref(primary_if);
+        return ret;
 }
 
 static void _hna_local_del(struct hlist_node *node, void *arg)
@@ -468,16 +483,26 @@ int hna_global_seq_print_text(struct seq_file *seq, void *offset)
         struct bat_priv *bat_priv = netdev_priv(net_dev);
         struct hashtable_t *hash = bat_priv->hna_global_hash;
         struct hna_global_entry *hna_global_entry;
+        struct hard_iface *primary_if;
         struct hlist_node *node;
         struct hlist_head *head;
         size_t buf_size, pos;
         char *buff;
-        int i;
+        int i, ret = 0;
 
-        if (!bat_priv->primary_if) {
-                return seq_printf(seq, "BATMAN mesh %s disabled - "
-                                  "please specify interfaces to enable it\n",
-                                  net_dev->name);
+        primary_if = primary_if_get_selected(bat_priv);
+        if (!primary_if) {
+                ret = seq_printf(seq, "BATMAN mesh %s disabled - please "
+                                 "specify interfaces to enable it\n",
+                                 net_dev->name);
+                goto out;
+        }
+
+        if (primary_if->if_status != IF_ACTIVE) {
+                ret = seq_printf(seq, "BATMAN mesh %s disabled - "
+                                 "primary interface not active\n",
+                                 net_dev->name);
+                goto out;
         }
 
         seq_printf(seq, "Globally announced HNAs received via the mesh %s\n",
@@ -499,7 +524,8 @@ int hna_global_seq_print_text(struct seq_file *seq, void *offset)
         buff = kmalloc(buf_size, GFP_ATOMIC);
         if (!buff) {
                 spin_unlock_bh(&bat_priv->hna_ghash_lock);
-                return -ENOMEM;
+                ret = -ENOMEM;
+                goto out;
         }
         buff[0] = '\0';
         pos = 0;
@@ -522,7 +548,10 @@ int hna_global_seq_print_text(struct seq_file *seq, void *offset)
 
         seq_printf(seq, "%s", buff);
         kfree(buff);
-        return 0;
+out:
+        if (primary_if)
+                hardif_free_ref(primary_if);
+        return ret;
 }
 
 static void _hna_global_del_orig(struct bat_priv *bat_priv,