From f83a7ea2075ca896f2dbf07672bac9cf3682ff74 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Wed, 17 Apr 2013 22:45:24 +0000 Subject: netfilter: xt_rpfilter: skip locally generated broadcast/multicast, too Alex Efros reported rpfilter module doesn't match following packets: IN=br.qemu SRC=192.168.2.1 DST=192.168.2.255 [ .. ] (netfilter bugzilla #814). Problem is that network stack arranges for the locally generated broadcasts to appear on the interface they were sent out, so the IFF_LOOPBACK check doesn't trigger. As -m rpfilter is restricted to PREROUTING, we can check for existing rtable instead, it catches locally-generated broad/multicast case, too. Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/ipv4/netfilter/ipt_rpfilter.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'net/ipv4') diff --git a/net/ipv4/netfilter/ipt_rpfilter.c b/net/ipv4/netfilter/ipt_rpfilter.c index c30130062cd6..c49dcd0284a0 100644 --- a/net/ipv4/netfilter/ipt_rpfilter.c +++ b/net/ipv4/netfilter/ipt_rpfilter.c @@ -66,6 +66,12 @@ static bool rpfilter_lookup_reverse(struct flowi4 *fl4, return dev_match; } +static bool rpfilter_is_local(const struct sk_buff *skb) +{ + const struct rtable *rt = skb_rtable(skb); + return rt && (rt->rt_flags & RTCF_LOCAL); +} + static bool rpfilter_mt(const struct sk_buff *skb, struct xt_action_param *par) { const struct xt_rpfilter_info *info; @@ -76,7 +82,7 @@ static bool rpfilter_mt(const struct sk_buff *skb, struct xt_action_param *par) info = par->matchinfo; invert = info->flags & XT_RPFILTER_INVERT; - if (par->in->flags & IFF_LOOPBACK) + if (rpfilter_is_local(skb)) return true ^ invert; iph = ip_hdr(skb); -- cgit v1.2.1