batman-adv/patches/0044-batman-adv-Fix-refcnt-leak-in-batadv_store_throughpu.patch

   1 From: Xiyu Yang <xiyuyang19@fudan.edu.cn>
   2 Date: Wed, 15 Apr 2020 16:35:21 +0800
   3 Subject: batman-adv: Fix refcnt leak in batadv_store_throughput_override
   4
   5 batadv_show_throughput_override() invokes batadv_hardif_get_by_netdev(),
   6 which gets a batadv_hard_iface object from net_dev with increased refcnt
   7 and its reference is assigned to a local pointer 'hard_iface'.
   8
   9 When batadv_store_throughput_override() returns, "hard_iface" becomes
  10 invalid, so the refcount should be decreased to keep refcount balanced.
  11
  12 The issue happens in one error path of
  13 batadv_store_throughput_override(). When batadv_parse_throughput()
  14 returns NULL, the refcnt increased by batadv_hardif_get_by_netdev() is
  15 not decreased, causing a refcnt leak.
  16
  17 Fix this issue by jumping to "out" label when batadv_parse_throughput()
  18 returns NULL.
  19
  20 Fixes: c513176e4b7a ("batman-adv: add throughput override attribute to hard_ifaces")
  21 Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
  22 Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
  23 Signed-off-by: Sven Eckelmann <sven@narfation.org>
  24
  25 Origin: upstream, https://git.open-mesh.org/batman-adv.git/commit/b69cd8bdbfd6fa7e61878c2fa9e6637406f40dd9
  26
  27 diff --git a/net/batman-adv/sysfs.c b/net/batman-adv/sysfs.c
  28 index 7f7de0b16aa7ab70986735fbd9b42fd02de8a924..976b038e53bf934332a39bad8a5509ca1aac0add 100644
  29 --- a/net/batman-adv/sysfs.c
  30 +++ b/net/batman-adv/sysfs.c
  31 @@ -1093,7 +1093,7 @@ static ssize_t batadv_store_throughput_override(struct kobject *kobj,
  32         ret = batadv_parse_throughput(net_dev, buff, "throughput_override",
  33                                       &tp_override);
  34         if (!ret)
  35 -               return count;
  36 +               goto out;
  37
  38         old_tp_override = atomic_read(&hard_iface->bat_v.throughput_override);
  39         if (old_tp_override == tp_override)