Patch "netfilter: nft_fib: Fix for rpath check with VRF devices" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    netfilter: nft_fib: Fix for rpath check with VRF devices

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     netfilter-nft_fib-fix-for-rpath-check-with-vrf-devic.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 9b9485f71a466622ccff17a5e99243b85ae86bf9
Author: Phil Sutter <phil@xxxxxx>
Date:   Wed Sep 21 13:07:31 2022 +0200

    netfilter: nft_fib: Fix for rpath check with VRF devices
    
    [ Upstream commit 2a8a7c0eaa8747c16aa4a48d573aa920d5c00a5c ]
    
    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>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/net/ipv4/netfilter/nft_fib_ipv4.c b/net/ipv4/netfilter/nft_fib_ipv4.c
index 03df986217b7..9e6f0f1275e2 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 92f3235fa287..602743f6dcee 100644
--- a/net/ipv6/netfilter/nft_fib_ipv6.c
+++ b/net/ipv6/netfilter/nft_fib_ipv6.c
@@ -37,6 +37,9 @@ 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)
@@ -193,7 +196,8 @@ 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);