Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [ 24/73] netfilter: xt_rpfilter: skip locally generated broadcast/multicast, too | Date | Thu, 9 May 2013 15:31:47 -0700 |
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3.8-stable review patch. If anyone has any objections, please let me know.
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From: Florian Westphal <fw@strlen.de>
commit f83a7ea2075ca896f2dbf07672bac9cf3682ff74 upstream.
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 <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- net/ipv4/netfilter/ipt_rpfilter.c | 8 +++++++- net/ipv6/netfilter/ip6t_rpfilter.c | 8 +++++++- 2 files changed, 14 insertions(+), 2 deletions(-)
--- a/net/ipv4/netfilter/ipt_rpfilter.c +++ b/net/ipv4/netfilter/ipt_rpfilter.c @@ -66,6 +66,12 @@ static bool rpfilter_lookup_reverse(stru 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_ 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); --- a/net/ipv6/netfilter/ip6t_rpfilter.c +++ b/net/ipv6/netfilter/ip6t_rpfilter.c @@ -71,6 +71,12 @@ static bool rpfilter_lookup_reverse6(con return ret; } +static bool rpfilter_is_local(const struct sk_buff *skb) +{ + const struct rt6_info *rt = (const void *) skb_dst(skb); + return rt && (rt->rt6i_flags & RTF_LOCAL); +} + static bool rpfilter_mt(const struct sk_buff *skb, struct xt_action_param *par) { const struct xt_rpfilter_info *info = par->matchinfo; @@ -78,7 +84,7 @@ static bool rpfilter_mt(const struct sk_ struct ipv6hdr *iph; bool invert = info->flags & XT_RPFILTER_INVERT; - if (par->in->flags & IFF_LOOPBACK) + if (rpfilter_is_local(skb)) return true ^ invert; iph = ipv6_hdr(skb);
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