netdev - [PATCH net 5/7] netfilter: nf_tables: make nft_set_do

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Message-ID: <20250910190308.13356-6-fw@strlen.de>
Date: Wed, 10 Sep 2025 21:03:06 +0200
From: Florian Westphal <fw@...len.de>
To: <netdev@...r.kernel.org>
Cc: Paolo Abeni <pabeni@...hat.com>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>,
	<netfilter-devel@...r.kernel.org>,
	pablo@...filter.org
Subject: [PATCH net 5/7] netfilter: nf_tables: make nft_set_do_lookup available unconditionally

This function was added for retpoline mitigation and is replaced by a
static inline helper if mitigations are not enabled.

Enable this helper function unconditionally so next patch can add a lookup
restart mechanism to fix possible false negatives while transactions are
in progress.

Adding lookup restarts in nft_lookup_eval doesn't work as nft_objref would
then need the same copypaste loop.

This patch is separate to ease review of the actual bug fix.

Suggested-by: Pablo Neira Ayuso <pablo@...filter.org>
Signed-off-by: Florian Westphal <fw@...len.de>
---
 include/net/netfilter/nf_tables_core.h | 10 ++--------
 net/netfilter/nft_lookup.c             | 17 ++++++++++++-----
 2 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/include/net/netfilter/nf_tables_core.h b/include/net/netfilter/nf_tables_core.h
index 6c2f483d9828..656e784714f3 100644
--- a/include/net/netfilter/nf_tables_core.h
+++ b/include/net/netfilter/nf_tables_core.h
@@ -109,17 +109,11 @@ nft_hash_lookup_fast(const struct net *net, const struct nft_set *set,
 const struct nft_set_ext *
 nft_hash_lookup(const struct net *net, const struct nft_set *set,
 		const u32 *key);
+#endif
+
 const struct nft_set_ext *
 nft_set_do_lookup(const struct net *net, const struct nft_set *set,
 		  const u32 *key);
-#else
-static inline const struct nft_set_ext *
-nft_set_do_lookup(const struct net *net, const struct nft_set *set,
-		  const u32 *key)
-{
-	return set->ops->lookup(net, set, key);
-}
-#endif
 
 /* called from nft_pipapo_avx2.c */
 const struct nft_set_ext *
diff --git a/net/netfilter/nft_lookup.c b/net/netfilter/nft_lookup.c
index 40c602ffbcba..2c6909bf1b40 100644
--- a/net/netfilter/nft_lookup.c
+++ b/net/netfilter/nft_lookup.c
@@ -24,11 +24,11 @@ struct nft_lookup {
 	struct nft_set_binding		binding;
 };
 
-#ifdef CONFIG_MITIGATION_RETPOLINE
-const struct nft_set_ext *
-nft_set_do_lookup(const struct net *net, const struct nft_set *set,
-		  const u32 *key)
+static const struct nft_set_ext *
+__nft_set_do_lookup(const struct net *net, const struct nft_set *set,
+		    const u32 *key)
 {
+#ifdef CONFIG_MITIGATION_RETPOLINE
 	if (set->ops == &nft_set_hash_fast_type.ops)
 		return nft_hash_lookup_fast(net, set, key);
 	if (set->ops == &nft_set_hash_type.ops)
@@ -51,10 +51,17 @@ nft_set_do_lookup(const struct net *net, const struct nft_set *set,
 		return nft_rbtree_lookup(net, set, key);
 
 	WARN_ON_ONCE(1);
+#endif
 	return set->ops->lookup(net, set, key);
 }
+
+const struct nft_set_ext *
+nft_set_do_lookup(const struct net *net, const struct nft_set *set,
+		  const u32 *key)
+{
+	return __nft_set_do_lookup(net, set, key);
+}
 EXPORT_SYMBOL_GPL(nft_set_do_lookup);
-#endif
 
 void nft_lookup_eval(const struct nft_expr *expr,
 		     struct nft_regs *regs,
-- 
2.49.1