batman-adv/patches/0047-batman-adv-Fix-segfault-when-writing-to-throughput_o.patch

   1 From: Sven Eckelmann <sven@narfation.org>
   2 Date: Fri, 31 Aug 2018 16:46:47 +0200
   3 Subject: batman-adv: Fix segfault when writing to throughput_override
   4
   5 The per hardif sysfs file "batman_adv/throughput_override" prints the
   6 resulting change as info text when the users writes to this file. It uses
   7 the helper function batadv_info to add it at the same time to the kernel
   8 ring buffer and to the batman-adv debug log (when CONFIG_BATMAN_ADV_DEBUG
   9 is enabled).
  10
  11 The function batadv_info requires as first parameter the batman-adv softif
  12 net_device. This parameter is then used to find the private buffer which
  13 contains the debug log for this batman-adv interface. But
  14 batadv_store_throughput_override used as first argument the slave
  15 net_device. This slave device doesn't have the batadv_priv private data
  16 which is access by batadv_info.
  17
  18 Writing to this file with CONFIG_BATMAN_ADV_DEBUG enabled can either lead
  19 to a segfault or to memory corruption.
  20
  21 Fixes: c513176e4b7a ("batman-adv: add throughput override attribute to hard_ifaces")
  22 Signed-off-by: Sven Eckelmann <sven@narfation.org>
  23 Acked-by: Marek Lindner <mareklindner@neomailbox.ch>
  24
  25 Origin: upstream, https://git.open-mesh.org/batman-adv.git/commit/ddf99b78e255530cbadc0f67656a549e19520280
  26
  27 diff --git a/net/batman-adv/sysfs.c b/net/batman-adv/sysfs.c
  28 index 17c844196eb26c9faf9fd543b88cd86cc1c2c029..ae22db3d6637dde2fcc238826a624ef2d6dbd8f5 100644
  29 --- a/net/batman-adv/sysfs.c
  30 +++ b/net/batman-adv/sysfs.c
  31 @@ -1078,8 +1078,9 @@ static ssize_t batadv_store_throughput_override(struct kobject *kobj,
  32         if (old_tp_override == tp_override)
  33                 goto out;
  34
  35 -       batadv_info(net_dev, "%s: Changing from: %u.%u MBit to: %u.%u MBit\n",
  36 -                   "throughput_override",
  37 +       batadv_info(hard_iface->soft_iface,
  38 +                   "%s: %s: Changing from: %u.%u MBit to: %u.%u MBit\n",
  39 +                   "throughput_override", net_dev->name,
  40                     old_tp_override / 10, old_tp_override % 10,
  41                     tp_override / 10, tp_override % 10);
  42