commit 36dc621ceca1be3ec885aeade5fdafbbcc452a6d upstream.
batman-adv is creating special debugfs directories in the init
net_namespace for each valid hard-interface (net_device). But it is
possible to rename a net_device to a completely different name then the
original one.
It can therefore happen that a user registers a new net_device which gets
the name "wlan0" assigned by default. batman-adv is also adding a new
directory under $debugfs/batman-adv/ with the name "wlan0".
The user then decides to rename this device to "wl_pri" and registers a
different device. The kernel may now decide to use the name "wlan0" again
for this new device. batman-adv will detect it as a valid net_device and
tries to create a directory with the name "wlan0" under
$debugfs/batman-adv/. But there already exists one with this name under
this path and thus this fails. batman-adv will detect a problem and
rollback the registering of this device.
batman-adv must therefore take care of renaming the debugfs directories
for hard-interfaces whenever it detects such a net_device rename.
Fixes: 5bc7c1eb44f2 ("batman-adv: add debugfs structure for information per interface")
Reported-by: John Soros <sorosj@xxxxxxxxx>
Signed-off-by: Sven Eckelmann <sven@xxxxxxxxxxxxx>
Signed-off-by: Simon Wunderlich <sw@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Sven Eckelmann <sven@xxxxxxxxxxxxx>
---
net/batman-adv/debugfs.c | 20 ++++++++++++++++++++
net/batman-adv/debugfs.h | 6 ++++++
net/batman-adv/hard-interface.c | 3 +++
3 files changed, 29 insertions(+)
diff --git a/net/batman-adv/debugfs.c b/net/batman-adv/debugfs.c
index c4c1e8030ba0..0d6fe6977be7 100644
--- a/net/batman-adv/debugfs.c
+++ b/net/batman-adv/debugfs.c
@@ -19,6 +19,7 @@
#include "main.h"
#include <linux/compiler.h>
+#include <linux/dcache.h>
#include <linux/debugfs.h>
#include <linux/device.h>
#include <linux/errno.h>
@@ -506,6 +507,25 @@ out:
return -ENOMEM;
}
+/**
+ * batadv_debugfs_rename_hardif() - Fix debugfs path for renamed hardif
+ * @hard_iface: hard interface which was renamed
+ */
+void batadv_debugfs_rename_hardif(struct batadv_hard_iface *hard_iface)
+{
+ const char *name = hard_iface->net_dev->name;
+ struct dentry *dir;
+ struct dentry *d;
+
+ dir = hard_iface->debug_dir;
+ if (!dir)
+ return;
+
+ d = debugfs_rename(dir->d_parent, dir, dir->d_parent, name);
+ if (!d)
+ pr_err("Can't rename debugfs dir to %s\n", name);
+}
+
/**
* batadv_debugfs_del_hardif - delete the base directory for a hard interface
* in debugfs.
diff --git a/net/batman-adv/debugfs.h b/net/batman-adv/debugfs.h
index 80ab8d6f0ab3..4b62b9f152a6 100644
--- a/net/batman-adv/debugfs.h
+++ b/net/batman-adv/debugfs.h
@@ -33,6 +33,7 @@ void batadv_debugfs_destroy(void);
int batadv_debugfs_add_meshif(struct net_device *dev);
void batadv_debugfs_del_meshif(struct net_device *dev);
int batadv_debugfs_add_hardif(struct batadv_hard_iface *hard_iface);
+void batadv_debugfs_rename_hardif(struct batadv_hard_iface *hard_iface);
void batadv_debugfs_del_hardif(struct batadv_hard_iface *hard_iface);
#else
@@ -60,6 +61,11 @@ int batadv_debugfs_add_hardif(struct batadv_hard_iface *hard_iface)
return 0;
}
+static inline
+void batadv_debugfs_rename_hardif(struct batadv_hard_iface *hard_iface)
+{
+}
+
static inline
void batadv_debugfs_del_hardif(struct batadv_hard_iface *hard_iface)
{
diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c
index 7c297cef20a7..d659441cc64e 100644
--- a/net/batman-adv/hard-interface.c
+++ b/net/batman-adv/hard-interface.c
@@ -780,6 +780,9 @@ static int batadv_hard_if_event(struct notifier_block *this,
if (hard_iface == primary_if)
batadv_primary_if_update_addr(bat_priv, NULL);
break;
+ case NETDEV_CHANGENAME:
+ batadv_debugfs_rename_hardif(hard_iface);
+ break;
default:
break;
}
--
2.20.1
