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Commit 032a4802 authored by Paolo Abeni's avatar Paolo Abeni Committed by David S. Miller
Browse files

ipv4: fix validate_source for VRF setup 



David reported breakages of VRF scenarios due to the
commit 6e617de8 ("net: avoid a full fib lookup when rp_filter is
disabled."): the local addresses based test is too strict when VRFs
are in place.

With this change we fall-back to a full lookup when custom fib rules
are in place; so that we address the VRF use case and possibly other
similar issues in non trivial setups.

v1 -> v2:
 - fix build breakage when CONFIG_IP_MULTIPLE_TABLES is not defined,
   reported by the kbuild test robot

Reported-by: default avatarDavid Ahern <dsahern@gmail.com>
Fixes: 6e617de8 ("net: avoid a full fib lookup when rp_filter is disabled.")
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
Acked-by: default avatarDavid Ahern <dsahern@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent dc82673f

net/ipv4/fib_frontend.c

+15 −3
Original line number Original line Diff line number Diff line
@@ -73,6 +73,11 @@ static int __net_init fib4_rules_init(struct net *net) 
	fib_free_table(main_table);

	fib_free_table(main_table);

	return -ENOMEM;

	return -ENOMEM;

}

}



static bool fib4_has_custom_rules(struct net *net)

{

	return false;

}

#else

#else





struct fib_table *fib_new_table(struct net *net, u32 id)

struct fib_table *fib_new_table(struct net *net, u32 id)
@@ -128,6 +133,11 @@ struct fib_table *fib_get_table(struct net *net, u32 id) 
	}

	}

	return NULL;

	return NULL;

}

}



static bool fib4_has_custom_rules(struct net *net)

{

	return net->ipv4.fib_has_custom_rules;

}

#endif /* CONFIG_IP_MULTIPLE_TABLES */

#endif /* CONFIG_IP_MULTIPLE_TABLES */





static void fib_replace_table(struct net *net, struct fib_table *old,

static void fib_replace_table(struct net *net, struct fib_table *old,
@@ -405,10 +415,12 @@ int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst, 
	    (dev->ifindex != oif || !IN_DEV_TX_REDIRECTS(idev))) {

	    (dev->ifindex != oif || !IN_DEV_TX_REDIRECTS(idev))) {

		if (IN_DEV_ACCEPT_LOCAL(idev))

		if (IN_DEV_ACCEPT_LOCAL(idev))

			goto ok;

			goto ok;

		/* if no local routes are added from user space we can check

		/* with custom local routes in place, checking local addresses

		 * for local addresses looking-up the ifaddr table

		 * only will be too optimistic, with custom rules, checking

		 * local addresses only can be too strict, e.g. due to vrf

		 */

		 */

		if (net->ipv4.fib_has_custom_local_routes)

		if (net->ipv4.fib_has_custom_local_routes ||

		    fib4_has_custom_rules(net))

			goto full_check;

			goto full_check;

		if (inet_lookup_ifaddr_rcu(net, src))

		if (inet_lookup_ifaddr_rcu(net, src))

			return -EINVAL;

			return -EINVAL;