[B.A.T.M.A.N.] [PATCH v2 2/2] batman-adv: filter ARP packets with invalid MAC addresses in DAT

Matthias Schiffer
2013-01-24T17:18:27Z

We never want multicast MAC addresses in the Distributed ARP Table, so it's
best to completely ignore ARP packets containing them where we expect unicast
addresses.

Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>
---
distributed-arp-table.c | 13 +++++++++++++
1 file changed, 13 insertions(+)

diff --git a/distributed-arp-table.c b/distributed-arp-table.c
index a35466a..c89a01e 100644
--- a/distributed-arp-table.c
+++ b/distributed-arp-table.c
@@ -738,6 +738,7 @@ static uint16_t batadv_arp_get_type(struct batadv_priv *bat_priv,
struct arphdr *arphdr;
struct ethhdr *ethhdr;
__be32 ip_src, ip_dst;
+ uint8_t *hw_src, *hw_dst;
uint16_t type = 0;

/* pull the ethernet header */
@@ -782,6 +783,18 @@ static uint16_t batadv_arp_get_type(struct batadv_priv *bat_priv,
ipv4_is_zeronet(ip_dst) || ipv4_is_lbcast(ip_dst))
goto out;

+ hw_src = batadv_arp_hw_src(skb, hdr_size);
+ if (is_zero_ether_addr(hw_src) || is_multicast_ether_addr(hw_src))
+ goto out;
+
+ /* we don't care for the destination MAC address in ARP requests */
+ if (arphdr->ar_op != htons(ARPOP_REQUEST)) {
+ hw_dst = batadv_arp_hw_dst(skb, hdr_size);
+ if (is_zero_ether_addr(hw_dst) ||
+ is_multicast_ether_addr(hw_dst))
+ goto out;
+ }
+
type = ntohs(arphdr->ar_op);
out:
return type;
--
1.8.1.1