Commit f872de81 authored Apr 15, 2020 by Xiyu Yang Committed by Simon Wunderlich Apr 21, 2020

batman-adv: Fix refcnt leak in batadv_show_throughput_override



batadv_show_throughput_override() invokes batadv_hardif_get_by_netdev(),
which gets a batadv_hard_iface object from net_dev with increased refcnt
and its reference is assigned to a local pointer 'hard_iface'.

When batadv_show_throughput_override() returns, "hard_iface" becomes
invalid, so the refcount should be decreased to keep refcount balanced.

The issue happens in the normal path of
batadv_show_throughput_override(), which forgets to decrease the refcnt
increased by batadv_hardif_get_by_netdev() before the function returns,
causing a refcnt leak.

Fix this issue by calling batadv_hardif_put() before the
batadv_show_throughput_override() returns in the normal path.

Fixes: 0b5ecc68 ("batman-adv: add throughput override attribute to hard_ifaces")
Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

parent fd0c42c4

net/batman-adv/sysfs.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -1190,6 +1190,7 @@ static ssize_t batadv_show_throughput_override(struct kobject *kobj,

		tp_override = atomic_read(&hard_iface->bat_v.throughput_override);

		batadv_hardif_put(hard_iface);
		return sprintf(buff, "%u.%u MBit\n", tp_override / 10,
		tp_override % 10);
		}

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