diff options
| author | Florian Westphal <fw@strlen.de> | 2013-04-17 22:45:24 +0000 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2013-04-19 00:11:59 +0200 |
| commit | f83a7ea2075ca896f2dbf07672bac9cf3682ff74 (patch) | |
| tree | ce21e50675072ee54018788ddea8b234daad4af4 /net | |
| parent | 5add189a125e6b497e31bffdaaed8145ec6d4984 (diff) | |
| download | lwn-f83a7ea2075ca896f2dbf07672bac9cf3682ff74.tar.gz lwn-f83a7ea2075ca896f2dbf07672bac9cf3682ff74.zip | |
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 <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/netfilter/ipt_rpfilter.c | 8 | ||||
| -rw-r--r-- | net/ipv6/netfilter/ip6t_rpfilter.c | 8 |
2 files changed, 14 insertions, 2 deletions
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); diff --git a/net/ipv6/netfilter/ip6t_rpfilter.c b/net/ipv6/netfilter/ip6t_rpfilter.c index 5060d54199ab..e0983f3648a6 100644 --- a/net/ipv6/netfilter/ip6t_rpfilter.c +++ b/net/ipv6/netfilter/ip6t_rpfilter.c @@ -71,6 +71,12 @@ static bool rpfilter_lookup_reverse6(const struct sk_buff *skb, 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_buff *skb, struct xt_action_param *par) 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); |