Re: [PATCH 6/8] netfilter: IPv6: initialize TOS field in REJECT target module

["Fernando Luis Vázquez Cao" <fernando@oss.ntt.co.jp>]

Hi Pablo,

Thank you for taking care of these patches, I really appreciate it.

I noticed that they have just been picked up by Linus. Could we get them
into the -stable and -longterm trees too?

1ed2f73d90fb49bcf5704aee7e9084adb882bfc5 (netfilter: IPv6: fix DSCP mangle code)
4319cc0cf5bb894b7368008cdf6dd20eb8868018 (netfilter: IPv6: initialize TOS field in REJECT target module)

Regards,
Fernando


On Tue, 2011-05-10 at 12:05 +0200, pablo@netfilter.org wrote:
> From: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
> 
> The IPv6 header is not zeroed out in alloc_skb so we must initialize
> it properly unless we want to see IPv6 packets with random TOS fields
> floating around. The current implementation resets the flow label
> but this could be changed if deemed necessary.
> 
> We stumbled upon this issue when trying to apply a mangle rule to
> the RST packet generated by the REJECT target module.
> 
> Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
> ---
>  net/ipv6/netfilter/ip6t_REJECT.c |    4 +++-
>  1 files changed, 3 insertions(+), 1 deletions(-)
> 
> diff --git a/net/ipv6/netfilter/ip6t_REJECT.c b/net/ipv6/netfilter/ip6t_REJECT.c
> index 28e7448..a5a4c5d 100644
> --- a/net/ipv6/netfilter/ip6t_REJECT.c
> +++ b/net/ipv6/netfilter/ip6t_REJECT.c
> @@ -45,6 +45,8 @@ static void send_reset(struct net *net, struct sk_buff *oldskb)
>  	int tcphoff, needs_ack;
>  	const struct ipv6hdr *oip6h = ipv6_hdr(oldskb);
>  	struct ipv6hdr *ip6h;
> +#define DEFAULT_TOS_VALUE	0x0U
> +	const __u8 tclass = DEFAULT_TOS_VALUE;
>  	struct dst_entry *dst = NULL;
>  	u8 proto;
>  	struct flowi6 fl6;
> @@ -124,7 +126,7 @@ static void send_reset(struct net *net, struct sk_buff *oldskb)
>  	skb_put(nskb, sizeof(struct ipv6hdr));
>  	skb_reset_network_header(nskb);
>  	ip6h = ipv6_hdr(nskb);
> -	ip6h->version = 6;
> +	*(__be32 *)ip6h =  htonl(0x60000000 | (tclass << 20));
>  	ip6h->hop_limit = ip6_dst_hoplimit(dst);
>  	ip6h->nexthdr = IPPROTO_TCP;
>  	ipv6_addr_copy(&ip6h->saddr, &oip6h->daddr);