[BRIDGE]: prevent bad forwarding table updates
Avoid poisoning of the bridge forwarding table by frames that have been
dropped by filtering. This prevents spoofed source addresses on hostile
side of bridge from causing packet leakage, a small but possible security
risk.
Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/bridge/br_stp_bpdu.c b/net/bridge/br_stp_bpdu.c
index b91a875..d071f1c 100644
--- a/net/bridge/br_stp_bpdu.c
+++ b/net/bridge/br_stp_bpdu.c
@@ -140,6 +140,9 @@
struct net_bridge *br = p->br;
unsigned char *buf;
+ /* insert into forwarding database after filtering to avoid spoofing */
+ br_fdb_update(p->br, p, eth_hdr(skb)->h_source);
+
/* need at least the 802 and STP headers */
if (!pskb_may_pull(skb, sizeof(header)+1) ||
memcmp(skb->data, header, sizeof(header)))