batman-adv/patches/0042-batman-adv-Fix-debugfs-path-for-renamed-hardif.patch

   1 From: Sven Eckelmann <sven@narfation.org>
   2 Date: Fri, 1 Jun 2018 19:24:23 +0200
   3 Subject: batman-adv: Fix debugfs path for renamed hardif
   4
   5 batman-adv is creating special debugfs directories in the init
   6 net_namespace for each valid hard-interface (net_device). But it is
   7 possible to rename a net_device to a completely different name then the
   8 original one.
   9
  10 It can therefore happen that a user registers a new net_device which gets
  11 the name "wlan0" assigned by default. batman-adv is also adding a new
  12 directory under $debugfs/batman-adv/ with the name "wlan0".
  13
  14 The user then decides to rename this device to "wl_pri" and registers a
  15 different device. The kernel may now decide to use the name "wlan0" again
  16 for this new device. batman-adv will detect it as a valid net_device and
  17 tries to create a directory with the name "wlan0" under
  18 $debugfs/batman-adv/. But there already exists one with this name under
  19 this path and thus this fails. batman-adv will detect a problem and
  20 rollback the registering of this device.
  21
  22 batman-adv must therefore take care of renaming the debugfs directories
  23 for hard-interfaces whenever it detects such a net_device rename.
  24
  25 Fixes: 3c926a01c8e8 ("batman-adv: add debugfs structure for information per interface")
  26 Reported-by: John Soros <sorosj@gmail.com>
  27 Signed-off-by: Sven Eckelmann <sven@narfation.org>
  28
  29 Origin: backport, https://git.open-mesh.org/batman-adv.git/commit/127086f503f6495518b95455efebee33d328f335
  30
  31 diff --git a/net/batman-adv/debugfs.c b/net/batman-adv/debugfs.c
  32 index 77925504379dac7d64777393ddae326b5d6d9505..a229d2d9acfd1f3d6fea071aa0df3bf06a0e2ecf 100644
  33 --- a/net/batman-adv/debugfs.c
  34 +++ b/net/batman-adv/debugfs.c
  35 @@ -18,6 +18,7 @@
  36  #include "debugfs.h"
  37  #include "main.h"
  38
  39 +#include <linux/dcache.h>
  40  #include <linux/debugfs.h>
  41  #include <linux/device.h>
  42  #include <linux/errno.h>
  43 @@ -337,6 +338,25 @@ out:
  44         return -ENOMEM;
  45  }
  46
  47 +/**
  48 + * batadv_debugfs_rename_hardif() - Fix debugfs path for renamed hardif
  49 + * @hard_iface: hard interface which was renamed
  50 + */
  51 +void batadv_debugfs_rename_hardif(struct batadv_hard_iface *hard_iface)
  52 +{
  53 +       const char *name = hard_iface->net_dev->name;
  54 +       struct dentry *dir;
  55 +       struct dentry *d;
  56 +
  57 +       dir = hard_iface->debug_dir;
  58 +       if (!dir)
  59 +               return;
  60 +
  61 +       d = debugfs_rename(dir->d_parent, dir, dir->d_parent, name);
  62 +       if (!d)
  63 +               pr_err("Can't rename debugfs dir to %s\n", name);
  64 +}
  65 +
  66  /**
  67   * batadv_debugfs_del_hardif - delete the base directory for a hard interface
  68   *  in debugfs.
  69 diff --git a/net/batman-adv/debugfs.h b/net/batman-adv/debugfs.h
  70 index e49121ee55f696547ddc9774ba6c425af2d49b57..3d9b684b862d0aa9d2380fbcb15fd4ef68a4511c 100644
  71 --- a/net/batman-adv/debugfs.h
  72 +++ b/net/batman-adv/debugfs.h
  73 @@ -31,6 +31,7 @@ void batadv_debugfs_destroy(void);
  74  int batadv_debugfs_add_meshif(struct net_device *dev);
  75  void batadv_debugfs_del_meshif(struct net_device *dev);
  76  int batadv_debugfs_add_hardif(struct batadv_hard_iface *hard_iface);
  77 +void batadv_debugfs_rename_hardif(struct batadv_hard_iface *hard_iface);
  78  void batadv_debugfs_del_hardif(struct batadv_hard_iface *hard_iface);
  79
  80  #else
  81 @@ -58,6 +59,11 @@ int batadv_debugfs_add_hardif(struct batadv_hard_iface *hard_iface)
  82         return 0;
  83  }
  84
  85 +static inline
  86 +void batadv_debugfs_rename_hardif(struct batadv_hard_iface *hard_iface)
  87 +{
  88 +}
  89 +
  90  static inline
  91  void batadv_debugfs_del_hardif(struct batadv_hard_iface *hard_iface)
  92  {
  93 diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c
  94 index ebeea5816a06b33c4944b01e40cee157c88bdff7..507eaff8582a8c58adc6d23abc42bb6c31d2816f 100644
  95 --- a/net/batman-adv/hard-interface.c
  96 +++ b/net/batman-adv/hard-interface.c
  97 @@ -1020,6 +1020,9 @@ static int batadv_hard_if_event(struct notifier_block *this,
  98                 if (batadv_is_wifi_hardif(hard_iface))
  99                         hard_iface->num_bcasts = BATADV_NUM_BCASTS_WIRELESS;
 100                 break;
 101 +       case NETDEV_CHANGENAME:
 102 +               batadv_debugfs_rename_hardif(hard_iface);
 103 +               break;
 104         default:
 105                 break;
 106         }