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>
---
net/ipv4/netfilter/nft_fib_ipv4.c | 3 +++
net/ipv6/netfilter/nft_fib_ipv6.c | 7 ++++++-
2 files changed, 9 insertions(+), 1 deletion(-)
diff --git a/net/ipv4/netfilter/nft_fib_ipv4.c b/net/ipv4/netfilter/nft_fib_ipv4.c
index b75cac69bd7e6..7ade04ff972d7 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);
+
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 8970d0b4faeb4..3f860e331580d 100644
--- a/net/ipv6/netfilter/nft_fib_ipv6.c
+++ b/net/ipv6/netfilter/nft_fib_ipv6.c
@@ -170,6 +170,10 @@ void nft_fib6_eval(const struct nft_expr *expr, struct nft_regs *regs,
else if (priv->flags & NFTA_FIB_F_OIF)
oif = nft_out(pkt);
+ if ((priv->flags & NFTA_FIB_F_IIF) &&
+ (netif_is_l3_master(oif) || netif_is_l3_slave(oif)))
+ fl6.flowi6_oif = oif->ifindex;
+
iph = skb_header_pointer(pkt->skb, noff, sizeof(_iph), &_iph);
if (!iph) {
regs->verdict.code = NFT_BREAK;
@@ -197,7 +201,8 @@ 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);
--
2.34.1
