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batman-adv: Fix debugfs path for renamed hardif

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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@gmail.com>
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>
This commit is contained in:
Sven Eckelmann 2020-03-16 23:30:27 +01:00 committed by Greg Kroah-Hartman
parent 90ae6475b1
commit 33dfa3bf0e
3 changed files with 30 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
net/batman-adv/debugfs.c
View File

@ -18,6 +18,7 @@
#include "debugfs.h"
#include "main.h"
#include <linux/dcache.h>
#include <linux/debugfs.h>
#include <linux/err.h>
#include <linux/errno.h>
@ -338,7 +339,26 @@ out:
}
/**
* batadv_debugfs_del_hardif - delete the base directory for a hard interface
* 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.
* @hard_iface: hard interface which is deleted.
*/

6
net/batman-adv/debugfs.h
View File

@ -31,6 +31,7 @@ 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
@ -58,6 +59,11 @@ 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)
{

3
net/batman-adv/hard-interface.c
View File

@ -1017,6 +1017,9 @@ static int batadv_hard_if_event(struct notifier_block *this,
if (batadv_is_wifi_hardif(hard_iface))
hard_iface->num_bcasts = BATADV_NUM_BCASTS_WIRELESS;
break;
case NETDEV_CHANGENAME:
batadv_debugfs_rename_hardif(hard_iface);
break;
default:
break;
}