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netfilter: ipt_rpfilter: remove the nh_scope test in rpfilter_lookup_reverse

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--accept-local  option works for res.type == RTN_LOCAL, which should be
from the local table, but there, the fib_info's nh->nh_scope =
RT_SCOPE_NOWHERE ( > RT_SCOPE_HOST). in fib_create_info().

	if (cfg->fc_scope == RT_SCOPE_HOST) {
		struct fib_nh *nh = fi->fib_nh;

		/* Local address is added. */
		if (nhs != 1 || nh->nh_gw)
			goto err_inval;
		nh->nh_scope = RT_SCOPE_NOWHERE;   <===
		nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif);
		err = -ENODEV;
		if (!nh->nh_dev)
			goto failure;

but in our rpfilter_lookup_reverse():

	if (dev_match || flags & XT_RPFILTER_LOOSE)
		return FIB_RES_NH(res).nh_scope <= RT_SCOPE_HOST;

if nh->nh_scope > RT_SCOPE_HOST, it will fail. --accept-local option
will never be passed.

it seems the test is bogus and can be removed to fix this issue.

	if (dev_match || flags & XT_RPFILTER_LOOSE)
		return FIB_RES_NH(res).nh_scope <= RT_SCOPE_HOST;

ipv6 does not have this issue.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
lucien 2015-10-06 21:03:07 +08:00 committed by Pablo Neira Ayuso
parent 6ece90f9a1
commit cc4998febd
1 changed files with 1 additions and 3 deletions
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4
net/ipv4/netfilter/ipt_rpfilter.c
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@ -61,9 +61,7 @@ static bool rpfilter_lookup_reverse(struct flowi4 *fl4,
if (FIB_RES_DEV(res) == dev)
dev_match = true;
#endif
if (dev_match || flags & XT_RPFILTER_LOOSE)
return FIB_RES_NH(res).nh_scope <= RT_SCOPE_HOST;
return dev_match;
return dev_match || flags & XT_RPFILTER_LOOSE;
}
static bool rpfilter_is_local(const struct sk_buff *skb)