From b081203732b8a12ea7700eeeb8e03e206088bb99 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Linus=20L=C3=BCssing?= Date: Mon, 16 Mar 2020 23:31:00 +0100 Subject: [PATCH] batman-adv: Fix multicast TT issues with bogus ROAM flags MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit commit a44ebeff6bbd6ef50db41b4195fca87b21aefd20 upstream. When a (broken) node wrongly sends multicast TT entries with a ROAM flag then this causes any receiving node to drop all entries for the same multicast MAC address announced by other nodes, leading to packet loss. Fix this DoS vector by only storing TT sync flags. For multicast TT non-sync'ing flag bits like ROAM are unused so far anyway. Fixes: 1d8ab8d3c176 ("batman-adv: Modified forwarding behaviour for multicast packets") Reported-by: Leonardo Mörlein Signed-off-by: Linus Lüssing Signed-off-by: Simon Wunderlich Signed-off-by: Greg Kroah-Hartman --- net/batman-adv/translation-table.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c index 6300454..d40d839 100644 --- a/net/batman-adv/translation-table.c +++ b/net/batman-adv/translation-table.c @@ -1708,7 +1708,8 @@ static bool batadv_tt_global_add(struct batadv_priv *bat_priv, ether_addr_copy(common->addr, tt_addr); common->vid = vid; - common->flags = flags & (~BATADV_TT_SYNC_MASK); + if (!is_multicast_ether_addr(common->addr)) + common->flags = flags & (~BATADV_TT_SYNC_MASK); tt_global_entry->roam_at = 0; /* node must store current time in case of roaming. This is @@ -1772,7 +1773,8 @@ static bool batadv_tt_global_add(struct batadv_priv *bat_priv, * TT_CLIENT_TEMP, therefore they have to be copied in the * client entry */ - common->flags |= flags & (~BATADV_TT_SYNC_MASK); + if (!is_multicast_ether_addr(common->addr)) + common->flags |= flags & (~BATADV_TT_SYNC_MASK); /* If there is the BATADV_TT_CLIENT_ROAM flag set, there is only * one originator left in the list and we previously received a -- 2.7.4