Commit b9fd14c2 authored by Sven Eckelmann's avatar Sven Eckelmann Committed by Simon Wunderlich
Browse files

batman-adv: Fix segfault when writing to throughput_override

The per hardif sysfs file "batman_adv/throughput_override" prints the
resulting change as info text when the users writes to this file. It uses
the helper function batadv_info to add it at the same time to the kernel
ring buffer and to the batman-adv debug log (when CONFIG_BATMAN_ADV_DEBUG
is enabled).

The function batadv_info requires as first parameter the batman-adv softif
net_device. This parameter is then used to find the private buffer which
contains the debug log for this batman-adv interface. But
batadv_store_throughput_override used as first argument the slave
net_device. This slave device doesn't have the batadv_priv private data
which is access by batadv_info.

Writing to this file with CONFIG_BATMAN_ADV_DEBUG enabled can either lead
to a segfault or to memory corruption.

Fixes: 0b5ecc68

 ("batman-adv: add throughput override attribute to hard_ifaces")
Signed-off-by: default avatarSven Eckelmann <>
Acked-by: default avatarMarek Lindner <>
Signed-off-by: default avatarSimon Wunderlich <>
parent 88d0895d
...@@ -1090,8 +1090,9 @@ static ssize_t batadv_store_throughput_override(struct kobject *kobj, ...@@ -1090,8 +1090,9 @@ static ssize_t batadv_store_throughput_override(struct kobject *kobj,
if (old_tp_override == tp_override) if (old_tp_override == tp_override)
goto out; goto out;
batadv_info(net_dev, "%s: Changing from: %u.%u MBit to: %u.%u MBit\n", batadv_info(hard_iface->soft_iface,
"throughput_override", "%s: %s: Changing from: %u.%u MBit to: %u.%u MBit\n",
"throughput_override", net_dev->name,
old_tp_override / 10, old_tp_override % 10, old_tp_override / 10, old_tp_override % 10,
tp_override / 10, tp_override % 10); tp_override / 10, tp_override % 10);
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