Merge tag 'nf-25-06-05' of git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf

Pablo Neira Ayuso says:

====================
Netfilter fixes for net

The following patchset contains Netfilter fixes for net:

1) Zero out the remainder in nft_pipapo AVX2 implementation, otherwise
   next lookup could bogusly report a mismatch. This is followed by two
   patches to update nft_pipapo selftests to cover for the previous bug.
   From Florian Westphal.

2) Check for reverse tuple too in case of esoteric NAT collisions for
   UDP traffic and extend selftest coverage. Also from Florian.

netfilter pull request 25-06-05

* tag 'nf-25-06-05' of git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf:
  selftests: netfilter: nft_nat.sh: add test for reverse clash with nat
  netfilter: nf_nat: also check reverse tuple to obtain clashing entry
  selftests: netfilter: nft_concat_range.sh: add datapath check for map fill bug
  selftests: netfilter: nft_concat_range.sh: prefer per element counters for testing
  netfilter: nf_set_pipapo_avx2: fix initial map fill
====================

Link: https://patch.msgid.link/20250605085735.52205-1-pablo@netfilter.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

2 files changed, 29 insertions, 4 deletions

diff --git a/net/netfilter/nf_nat_core.c b/net/netfilter/nf_nat_core.c
index aad84aabd7f1..f391cd267922 100644
--- a/net/netfilter/nf_nat_core.c
+++ b/net/netfilter/nf_nat_core.c
@@ -248,7 +248,7 @@ static noinline bool
 nf_nat_used_tuple_new(const struct nf_conntrack_tuple *tuple,
 		      const struct nf_conn *ignored_ct)
 {
-	static const unsigned long uses_nat = IPS_NAT_MASK | IPS_SEQ_ADJUST_BIT;
+	static const unsigned long uses_nat = IPS_NAT_MASK | IPS_SEQ_ADJUST;
 	const struct nf_conntrack_tuple_hash *thash;
 	const struct nf_conntrack_zone *zone;
 	struct nf_conn *ct;
@@ -287,8 +287,14 @@ nf_nat_used_tuple_new(const struct nf_conntrack_tuple *tuple,
 	zone = nf_ct_zone(ignored_ct);
 
 	thash = nf_conntrack_find_get(net, zone, tuple);
-	if (unlikely(!thash)) /* clashing entry went away */
-		return false;
+	if (unlikely(!thash)) {
+		struct nf_conntrack_tuple reply;
+
+		nf_ct_invert_tuple(&reply, tuple);
+		thash = nf_conntrack_find_get(net, zone, &reply);
+		if (!thash) /* clashing entry went away */
+			return false;
+	}
 
 	ct = nf_ct_tuplehash_to_ctrack(thash);
 
diff --git a/net/netfilter/nft_set_pipapo_avx2.c b/net/netfilter/nft_set_pipapo_avx2.c
index c15db28c5ebc..be7c16c79f71 100644
--- a/net/netfilter/nft_set_pipapo_avx2.c
+++ b/net/netfilter/nft_set_pipapo_avx2.c
@@ -1114,6 +1114,25 @@ bool nft_pipapo_avx2_estimate(const struct nft_set_desc *desc, u32 features,
 }
 
 /**
+ * pipapo_resmap_init_avx2() - Initialise result map before first use
+ * @m:		Matching data, including mapping table
+ * @res_map:	Result map
+ *
+ * Like pipapo_resmap_init() but do not set start map bits covered by the first field.
+ */
+static inline void pipapo_resmap_init_avx2(const struct nft_pipapo_match *m, unsigned long *res_map)
+{
+	const struct nft_pipapo_field *f = m->f;
+	int i;
+
+	/* Starting map doesn't need to be set to all-ones for this implementation,
+	 * but we do need to zero the remaining bits, if any.
+	 */
+	for (i = f->bsize; i < m->bsize_max; i++)
+		res_map[i] = 0ul;
+}
+
+/**
  * nft_pipapo_avx2_lookup() - Lookup function for AVX2 implementation
  * @net:	Network namespace
  * @set:	nftables API set representation
@@ -1171,7 +1190,7 @@ bool nft_pipapo_avx2_lookup(const struct net *net, const struct nft_set *set,
 	res  = scratch->map + (map_index ? m->bsize_max : 0);
 	fill = scratch->map + (map_index ? 0 : m->bsize_max);
 
-	/* Starting map doesn't need to be set for this implementation */
+	pipapo_resmap_init_avx2(m, res);
 
 	nft_pipapo_avx2_prepare();