On Wed, Sep 28, 2022 at 01:39:08PM +0200, Florian Westphal wrote:
> From: Phil Sutter <phil@xxxxxx>
>
> Analogous to commit b575b24b8eee3 ("netfilter: Fix rpfilter
> dropping vrf packets by mistake") but for nftables fib expression:
> Add special treatment of VRF devices so that typical reverse path
> filtering via 'fib saddr . iif oif' expression works as expected.
>
> Fixes: f6d0cbcf09c50 ("netfilter: nf_tables: add fib expression")
> Signed-off-by: Phil Sutter <phil@xxxxxx>
> Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
> ---
> net/ipv4/netfilter/nft_fib_ipv4.c | 3 +++
> net/ipv6/netfilter/nft_fib_ipv6.c | 6 +++++-
> 2 files changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/net/ipv4/netfilter/nft_fib_ipv4.c b/net/ipv4/netfilter/nft_fib_ipv4.c
> index b75cac69bd7e..7ade04ff972d 100644
> --- a/net/ipv4/netfilter/nft_fib_ipv4.c
> +++ b/net/ipv4/netfilter/nft_fib_ipv4.c
> @@ -83,6 +83,9 @@ void nft_fib4_eval(const struct nft_expr *expr, struct nft_regs *regs,
> else
> oif = NULL;
>
> + if (priv->flags & NFTA_FIB_F_IIF)
> + fl4.flowi4_oif = l3mdev_master_ifindex_rcu(oif);
> +
Shouldn't we set .flowi4_l3mdev instead of .flowi4_oif?
> if (nft_hook(pkt) == NF_INET_PRE_ROUTING &&
> nft_fib_is_loopback(pkt->skb, nft_in(pkt))) {
> nft_fib_store_result(dest, priv, nft_in(pkt));
> diff --git a/net/ipv6/netfilter/nft_fib_ipv6.c b/net/ipv6/netfilter/nft_fib_ipv6.c
> index 8970d0b4faeb..1d7e520d9966 100644
> --- a/net/ipv6/netfilter/nft_fib_ipv6.c
> +++ b/net/ipv6/netfilter/nft_fib_ipv6.c
> @@ -41,6 +41,9 @@ static int nft_fib6_flowi_init(struct flowi6 *fl6, const struct nft_fib *priv,
> if (ipv6_addr_type(&fl6->daddr) & IPV6_ADDR_LINKLOCAL) {
> lookup_flags |= RT6_LOOKUP_F_IFACE;
> fl6->flowi6_oif = get_ifindex(dev ? dev : pkt->skb->dev);
> + } else if ((priv->flags & NFTA_FIB_F_IIF) &&
> + (netif_is_l3_master(dev) || netif_is_l3_slave(dev))) {
> + fl6->flowi6_oif = dev->ifindex;
> }
>
> if (ipv6_addr_type(&fl6->saddr) & IPV6_ADDR_UNICAST)
> @@ -197,7 +200,8 @@ void nft_fib6_eval(const struct nft_expr *expr, struct nft_regs *regs,
> if (rt->rt6i_flags & (RTF_REJECT | RTF_ANYCAST | RTF_LOCAL))
> goto put_rt_err;
>
> - if (oif && oif != rt->rt6i_idev->dev)
> + if (oif && oif != rt->rt6i_idev->dev &&
> + l3mdev_master_ifindex_rcu(rt->rt6i_idev->dev) != oif->ifindex)
> goto put_rt_err;
>
> nft_fib_store_result(dest, priv, rt->rt6i_idev->dev);
> --
> 2.35.1
>
