[PATCH 1/1] bridge: stp: ensure mac header is set

[PATCH 1/1] bridge: stp: ensure mac header is set

[Florian Westphal]

commit bf9ae5386bca8836c16e69ab8fdbe46767d7452a
(llc: use dev_hard_header) removed the
skb_reset_mac_header call from llc_mac_hdr_init.

This seems fine itself, but br_send_bpdu() invokes ebtables LOCAL_OUT.

We oops in ebt_basic_match() because it assumes eth_hdr(skb) returns
a meaningful result.

Cc: acme@ghostprotocols.net
References: https://bugzilla.kernel.org/show_bug.cgi?id=24532
Signed-off-by: Florian Westphal <fw@strlen.de>
---
 net/bridge/br_stp_bpdu.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/net/bridge/br_stp_bpdu.c b/net/bridge/br_stp_bpdu.c
index 3d9a55d..289646e 100644
--- a/net/bridge/br_stp_bpdu.c
+++ b/net/bridge/br_stp_bpdu.c
@@ -50,6 +50,8 @@ static void br_send_bpdu(struct net_bridge_port *p,
 
 	llc_mac_hdr_init(skb, p->dev->dev_addr, p->br->group_addr);
 
+	skb_reset_mac_header(skb);
+
 	NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,
 		dev_queue_xmit);
 }
-- 
1.7.2.2

Re: [PATCH 1/1] bridge: stp: ensure mac header is set

[David Miller]

From: Florian Westphal <fw@strlen.de>
Date: Mon,  3 Jan 2011 15:16:28 +0100

> commit bf9ae5386bca8836c16e69ab8fdbe46767d7452a
> (llc: use dev_hard_header) removed the
> skb_reset_mac_header call from llc_mac_hdr_init.
> 
> This seems fine itself, but br_send_bpdu() invokes ebtables LOCAL_OUT.
> 
> We oops in ebt_basic_match() because it assumes eth_hdr(skb) returns
> a meaningful result.
> 
> Cc: acme@ghostprotocols.net
> References: https://bugzilla.kernel.org/show_bug.cgi?id=24532
> Signed-off-by: Florian Westphal <fw@strlen.de>

Applied and queued up for -stable, thanks Florian.