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authorStephen Hemminger <shemminger@osdl.org>2005-05-29 14:15:55 -0700
committerDavid S. Miller <davem@davemloft.net>2005-05-29 14:15:55 -0700
commit85967bb46dd1f8f2c49b85a313866c00ac0c9b59 (patch)
tree3de44cb857e648d57e74baa047a0c89a96a00893 /net
parent81d35307dd468b92fe8c58797abb13c62e3e64dd (diff)
[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>
Diffstat (limited to 'net')
-rw-r--r--net/bridge/br_input.c6
-rw-r--r--net/bridge/br_stp_bpdu.c3
2 files changed, 7 insertions, 2 deletions
diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
index 2b1cce46cab4..2aa5dda24a08 100644
--- a/net/bridge/br_input.c
+++ b/net/bridge/br_input.c
@@ -54,6 +54,9 @@ int br_handle_frame_finish(struct sk_buff *skb)
struct net_bridge_fdb_entry *dst;
int passedup = 0;
+ /* insert into forwarding database after filtering to avoid spoofing */
+ br_fdb_update(p->br, p, eth_hdr(skb)->h_source);
+
if (br->dev->flags & IFF_PROMISC) {
struct sk_buff *skb2;
@@ -108,8 +111,7 @@ int br_handle_frame(struct net_bridge_port *p, struct sk_buff **pskb)
if (!is_valid_ether_addr(eth_hdr(skb)->h_source))
goto err;
- if (p->state == BR_STATE_LEARNING ||
- p->state == BR_STATE_FORWARDING)
+ if (p->state == BR_STATE_LEARNING)
br_fdb_update(p->br, p, eth_hdr(skb)->h_source);
if (p->br->stp_enabled &&
diff --git a/net/bridge/br_stp_bpdu.c b/net/bridge/br_stp_bpdu.c
index b91a875aca01..d071f1c9ad0b 100644
--- a/net/bridge/br_stp_bpdu.c
+++ b/net/bridge/br_stp_bpdu.c
@@ -140,6 +140,9 @@ int br_stp_handle_bpdu(struct sk_buff *skb)
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)))