From: Liping Zhang <zlpnobody@xxxxxxxxx>
In general, we haven't do routing lookup in PREROUTING hook, so it's
very likely that fib4/6_is_local will not be met. Then the *dest will
be set to 0 because we do nothing when the fib result is RTN_LOCAL.
So if the user want to drop all packets which cannot be routed,
and input the following nft rule:
# nft add rule filter prerouting fib daddr oif eq 0 drop
Then all the packets which destinate to local will be dropped
incorrectly.
Fixes: f6d0cbcf09c5 ("netfilter: nf_tables: add fib expression")
Signed-off-by: Liping Zhang <zlpnobody@xxxxxxxxx>
---
net/ipv4/netfilter/nft_fib_ipv4.c | 3 ++-
net/ipv6/netfilter/nft_fib_ipv6.c | 8 ++++++--
2 files changed, 8 insertions(+), 3 deletions(-)
diff --git a/net/ipv4/netfilter/nft_fib_ipv4.c b/net/ipv4/netfilter/nft_fib_ipv4.c
index 2581363..2107775 100644
--- a/net/ipv4/netfilter/nft_fib_ipv4.c
+++ b/net/ipv4/netfilter/nft_fib_ipv4.c
@@ -130,7 +130,8 @@ void nft_fib4_eval(const struct nft_expr *expr, struct nft_regs *regs,
switch (res.type) {
case RTN_UNICAST:
break;
- case RTN_LOCAL: /* should not appear here, see fib4_is_local() above */
+ case RTN_LOCAL:
+ nft_fib_store_result(dest, priv->result, pkt, LOOPBACK_IFINDEX);
return;
default:
break;
diff --git a/net/ipv6/netfilter/nft_fib_ipv6.c b/net/ipv6/netfilter/nft_fib_ipv6.c
index c947aad..5e2de1b 100644
--- a/net/ipv6/netfilter/nft_fib_ipv6.c
+++ b/net/ipv6/netfilter/nft_fib_ipv6.c
@@ -175,8 +175,12 @@ void nft_fib6_eval(const struct nft_expr *expr, struct nft_regs *regs,
if (rt->dst.error)
goto put_rt_err;
- /* Should not see RTF_LOCAL here */
- if (rt->rt6i_flags & (RTF_REJECT | RTF_ANYCAST | RTF_LOCAL))
+ if (rt->rt6i_flags & RTF_LOCAL) {
+ nft_fib_store_result(dest, priv->result, pkt, LOOPBACK_IFINDEX);
+ goto put_rt_err;
+ }
+
+ if (rt->rt6i_flags & (RTF_REJECT | RTF_ANYCAST))
goto put_rt_err;
if (oif && oif != rt->rt6i_idev->dev) {
--
2.5.5
--
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