Repository : ssh://git@open-mesh.org/batman-adv
On branch : master
commit 230222a7acd5fcea4471b1c2411fc9d7da9ebb0f Author: Sven Eckelmann sven@narfation.org Date: Sun Jul 7 23:04:57 2019 +0200
batman-adv: Fix deletion of RTR(4|6) mcast list entries
The multicast code uses the lists bat_priv->mcast.want_all_rtr*_list to store all all originator nodes which don't have the flag no-RTR4 or no-RTR6 set. When an originator is purged, it has to be removed from these lists.
Since all entries without the BATADV_MCAST_WANT_NO_RTR4/6 are stored in these lists, they have to be handled like entries which have these flags set to force the update routines to remove them from the lists when purging the originator.
Not doing so will leave a pointer to a freed memory region inside the list. Trying to operate on these lists will then cause an use-after-free error:
BUG: KASAN: use-after-free in batadv_mcast_want_rtr4_update+0x335/0x3a0 [batman_adv] Write of size 8 at addr ffff888007b41a38 by task swapper/0/0
Fixes: 0a7733468f95 ("batman-adv: mcast: detect, distribute and maintain multicast router presence") Signed-off-by: Sven Eckelmann sven@narfation.org Acked-by: Linus Lüssing linus.luessing@c0d3.blue
230222a7acd5fcea4471b1c2411fc9d7da9ebb0f net/batman-adv/multicast.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/net/batman-adv/multicast.c b/net/batman-adv/multicast.c index 67d7f830..ca02379c 100644 --- a/net/batman-adv/multicast.c +++ b/net/batman-adv/multicast.c @@ -2420,8 +2420,10 @@ void batadv_mcast_purge_orig(struct batadv_orig_node *orig) batadv_mcast_want_unsnoop_update(bat_priv, orig, BATADV_NO_FLAGS); batadv_mcast_want_ipv4_update(bat_priv, orig, BATADV_NO_FLAGS); batadv_mcast_want_ipv6_update(bat_priv, orig, BATADV_NO_FLAGS); - batadv_mcast_want_rtr4_update(bat_priv, orig, BATADV_NO_FLAGS); - batadv_mcast_want_rtr6_update(bat_priv, orig, BATADV_NO_FLAGS); + batadv_mcast_want_rtr4_update(bat_priv, orig, + BATADV_MCAST_WANT_NO_RTR4); + batadv_mcast_want_rtr6_update(bat_priv, orig, + BATADV_MCAST_WANT_NO_RTR6);
spin_unlock_bh(&orig->mcast_handler_lock); }