Commit 04954b2d authored Jun 07, 2018 by Linus Lüssing Committed by Greg Kroah-Hartman Aug 24, 2018

batman-adv: Fix multicast TT issues with bogus ROAM flags



[ Upstream commit a44ebeff6bbd6ef50db41b4195fca87b21aefd20 ]

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: 1d8ab8d3 ("batman-adv: Modified forwarding behaviour for multicast packets")
Reported-by: Leonardo Mörlein <me@irrelefant.net>
Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 44fed77f

net/batman-adv/translation-table.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -1679,6 +1679,7 @@ static bool batadv_tt_global_add(struct batadv_priv *bat_priv,
		ether_addr_copy(common->addr, tt_addr);
		common->vid = vid;

		if (!is_multicast_ether_addr(common->addr))
		common->flags = flags & (~BATADV_TT_SYNC_MASK);

		tt_global_entry->roam_at = 0;
		@@ -1743,6 +1744,7 @@ static bool batadv_tt_global_add(struct batadv_priv *bat_priv,
		* TT_CLIENT_TEMP, therefore they have to be copied in the
		* client entry
		*/
		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