提交 f83a7ea2 编写于 作者: F Florian Westphal 提交者: Pablo Neira Ayuso

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: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>
上级 5add189a
......@@ -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);
......
......@@ -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);
......
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