[PATCH 5.4 024/129] batman-adv: Fix own OGM check in aggregated OGMs

From: Greg Kroah-Hartman
Date: Tue Sep 08 2020 - 14:11:27 EST

From: Linus Lüssing <linus.luessing@xxxxxxxxx>

[ Upstream commit d8bf0c01642275c7dca1e5d02c34e4199c200b1f ]

The own OGM check is currently misplaced and can lead to the following

For one thing we might receive an aggregated OGM from a neighbor node
which has our own OGM in the first place. We would then not only skip
our own OGM but erroneously also any other, following OGM in the

For another, we might receive an OGM aggregate which has our own OGM in
a place other then the first one. Then we would wrongly not skip this
OGM, leading to populating the orginator and gateway table with ourself.

Fixes: 9323158ef9f4 ("batman-adv: OGMv2 - implement originators logic")
Signed-off-by: Linus Lüssing <linus.luessing@xxxxxxxxx>
Signed-off-by: Sven Eckelmann <sven@xxxxxxxxxxxxx>
Signed-off-by: Simon Wunderlich <sw@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
net/batman-adv/bat_v_ogm.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/net/batman-adv/bat_v_ogm.c b/net/batman-adv/bat_v_ogm.c
index a9e7540c56918..3165f6ff8ee71 100644
--- a/net/batman-adv/bat_v_ogm.c
+++ b/net/batman-adv/bat_v_ogm.c
@@ -878,6 +878,12 @@ static void batadv_v_ogm_process(const struct sk_buff *skb, int ogm_offset,
ntohl(ogm_packet->seqno), ogm_throughput, ogm_packet->ttl,
ogm_packet->version, ntohs(ogm_packet->tvlv_len));

+ if (batadv_is_my_mac(bat_priv, ogm_packet->orig)) {
+ batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
+ "Drop packet: originator packet from ourself\n");
+ return;
+ }
/* If the throughput metric is 0, immediately drop the packet. No need
* to create orig_node / neigh_node for an unusable route.
@@ -1005,11 +1011,6 @@ int batadv_v_ogm_packet_recv(struct sk_buff *skb,
if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
goto free_skb;

- ogm_packet = (struct batadv_ogm2_packet *)skb->data;
- if (batadv_is_my_mac(bat_priv, ogm_packet->orig))
- goto free_skb;
batadv_inc_counter(bat_priv, BATADV_CNT_MGMT_RX);
batadv_add_counter(bat_priv, BATADV_CNT_MGMT_RX_BYTES,
skb->len + ETH_HLEN);