From 40e220b4218bb3d278e5e8cc04ccdfd1c7ff8307 Mon Sep 17 00:00:00 2001 From: Sven Eckelmann Date: Thu, 3 Oct 2019 17:02:01 +0200 Subject: batman-adv: Avoid free/alloc race when handling OGM buffer Each slave interface of an B.A.T.M.A.N. IV virtual interface has an OGM packet buffer which is initialized using data from netdevice notifier and other rtnetlink related hooks. It is sent regularly via various slave interfaces of the batadv virtual interface and in this process also modified (realloced) to integrate additional state information via TVLV containers. It must be avoided that the worker item is executed without a common lock with the netdevice notifier/rtnetlink helpers. Otherwise it can either happen that half modified/freed data is sent out or functions modifying the OGM buffer try to access already freed memory regions. Reported-by: syzbot+0cc629f19ccb8534935b@syzkaller.appspotmail.com Fixes: c6c8fea29769 ("net: Add batman-adv meshing protocol") Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich --- net/batman-adv/hard-interface.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'net/batman-adv/hard-interface.c') diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c index c90e47342bb0..afb52282d5bd 100644 --- a/net/batman-adv/hard-interface.c +++ b/net/batman-adv/hard-interface.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include #include @@ -929,6 +930,7 @@ batadv_hardif_add_interface(struct net_device *net_dev) INIT_LIST_HEAD(&hard_iface->list); INIT_HLIST_HEAD(&hard_iface->neigh_list); + mutex_init(&hard_iface->bat_iv.ogm_buff_mutex); spin_lock_init(&hard_iface->neigh_list_lock); kref_init(&hard_iface->refcount); -- cgit v1.2.3