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: Sven Eckelmann sven@narfation.org --- 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; }