Repository : ssh://git@open-mesh.org/batman-adv

On branch : maint

commit ddf99b78e255530cbadc0f67656a549e19520280 Author: Sven Eckelmann sven@narfation.org Date: Fri Aug 31 16:46:47 2018 +0200

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: c513176e4b7a ("batman-adv: add throughput override attribute to hard_ifaces") Signed-off-by: Sven Eckelmann sven@narfation.org Acked-by: Marek Lindner mareklindner@neomailbox.ch

ddf99b78e255530cbadc0f67656a549e19520280 net/batman-adv/sysfs.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/net/batman-adv/sysfs.c b/net/batman-adv/sysfs.c index f2eef43..3a76e89 100644 --- a/net/batman-adv/sysfs.c +++ b/net/batman-adv/sysfs.c @@ -1090,8 +1090,9 @@ static ssize_t batadv_store_throughput_override(struct kobject *kobj, if (old_tp_override == tp_override) goto out;

- batadv_info(net_dev, "%s: Changing from: %u.%u MBit to: %u.%u MBit\n", - "throughput_override", + batadv_info(hard_iface->soft_iface, + "%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, tp_override / 10, tp_override % 10);