netdev - Re: [net-next PATCH] net: bridge: fix for bridging 802.1Q without REORDER

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20150911122445.53cdfbcf@urahara>
Date:	Fri, 11 Sep 2015 12:24:45 -0700
From:	Stephen Hemminger <stephen@...workplumber.org>
To:	Phil Sutter <phil@....cc>
Cc:	bridge@...ts.linux-foundation.org, netdev@...r.kernel.org
Subject: Re: [net-next PATCH] net: bridge: fix for bridging 802.1Q without
 REORDER_HDR

On Fri, 11 Sep 2015 21:22:03 +0200
Phil Sutter <phil@....cc> wrote:

> When forwarding packets from an 802.1Q interface with REORDER_HDR set to
> zero, the VLAN header previously inserted by vlan_do_receive() needs to
> be stripped from the packet and the mac_header adjustment undone,
> otherwise a tagged frame with first four bytes missing will be
> transmitted.
> 
> Signed-off-by: Phil Sutter <phil@....cc>
> ---
>  net/bridge/br_input.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
> index f921a5d..e4e3fc7 100644
> --- a/net/bridge/br_input.c
> +++ b/net/bridge/br_input.c
> @@ -288,6 +288,16 @@ rx_handler_result_t br_handle_frame(struct sk_buff **pskb)
>  	}
>  
>  forward:
> +	if (is_vlan_dev(skb->dev) &&
> +	    !(vlan_dev_priv(skb->dev)->flags & VLAN_FLAG_REORDER_HDR)) {
> +		unsigned int offset = skb->data - skb_mac_header(skb);
> +
> +		skb_push(skb, offset);
> +		memmove(skb->data + VLAN_HLEN, skb->data, 2 * ETH_ALEN);
> +		skb->mac_header += VLAN_HLEN;
> +		skb_pull(skb, offset);
> +		skb_reset_mac_len(skb);
> +	}
>  	switch (p->state) {
>  	case BR_STATE_FORWARDING:
>  		rhook = rcu_dereference(br_should_route_hook);

Thanks for finding this. Is this a new thing or has it always been there?

Sorry, this looks so special case it doesn't seem like a good idea.
Something is broken in VLAN handling if this is required.
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html