[pve-devel] [PATCH pve-kernel 4/5] kernel: backport: netfilter: nf_tables: make nft_set_do_lookup available unconditionally

[Gabriel Goller <g.goller@proxmox.com>]

Helper for the actual bugfix.

Signed-off-by: Gabriel Goller <g.goller@proxmox.com>
---
 ...les-make-nft_set_do_lookup-available.patch | 86 +++++++++++++++++++
 1 file changed, 86 insertions(+)
 create mode 100644 patches/kernel/0017-netfilter-nf_tables-make-nft_set_do_lookup-available.patch

diff --git a/patches/kernel/0017-netfilter-nf_tables-make-nft_set_do_lookup-available.patch b/patches/kernel/0017-netfilter-nf_tables-make-nft_set_do_lookup-available.patch
new file mode 100644
index 000000000000..0194b7e7776f
--- /dev/null
+++ b/patches/kernel/0017-netfilter-nf_tables-make-nft_set_do_lookup-available.patch
@@ -0,0 +1,86 @@
+From 35120b5cb4467a234f4ffecc52c7ff6630a31907 Mon Sep 17 00:00:00 2001
+From: Gabriel Goller <g.goller@proxmox.com>
+Date: Wed, 10 Sep 2025 12:10:11 +0200
+Subject: [PATCH 4/5] 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@netfilter.org>
+Signed-off-by: Florian Westphal <fw@strlen.de>
+Signed-off-by: Gabriel Goller <g.goller@proxmox.com>
+---
+ include/net/netfilter/nf_tables_core.h | 10 ++--------
+ net/netfilter/nft_lookup.c             | 11 ++++++++---
+ 2 files changed, 10 insertions(+), 11 deletions(-)
+
+diff --git a/include/net/netfilter/nf_tables_core.h b/include/net/netfilter/nf_tables_core.h
+index 03b6165756fc..04fc4a411a86 100644
+--- a/include/net/netfilter/nf_tables_core.h
++++ b/include/net/netfilter/nf_tables_core.h
+@@ -105,16 +105,10 @@ bool nft_hash_lookup_fast(const struct net *net,
+ 			  const u32 *key, const struct nft_set_ext **ext);
+ bool nft_hash_lookup(const struct net *net, const struct nft_set *set,
+ 		     const u32 *key, const struct nft_set_ext **ext);
++#endif
++
+ bool nft_set_do_lookup(const struct net *net, const struct nft_set *set,
+ 		       const u32 *key, const struct nft_set_ext **ext);
+-#else
+-static inline bool
+-nft_set_do_lookup(const struct net *net, const struct nft_set *set,
+-		  const u32 *key, const struct nft_set_ext **ext)
+-{
+-	return set->ops->lookup(net, set, key, ext);
+-}
+-#endif
+ 
+ /* called from nft_pipapo_avx2.c */
+ bool nft_pipapo_lookup(const struct net *net, const struct nft_set *set,
+diff --git a/net/netfilter/nft_lookup.c b/net/netfilter/nft_lookup.c
+index 63ef832b8aa7..7d0add1041bb 100644
+--- a/net/netfilter/nft_lookup.c
++++ b/net/netfilter/nft_lookup.c
+@@ -24,10 +24,10 @@ struct nft_lookup {
+ 	struct nft_set_binding		binding;
+ };
+ 
+-#ifdef CONFIG_MITIGATION_RETPOLINE
+-bool nft_set_do_lookup(const struct net *net, const struct nft_set *set,
++static bool __nft_set_do_lookup(const struct net *net, const struct nft_set *set,
+ 		       const u32 *key, const struct nft_set_ext **ext)
+ {
++#ifdef CONFIG_MITIGATION_RETPOLINE
+ 	if (set->ops == &nft_set_hash_fast_type.ops)
+ 		return nft_hash_lookup_fast(net, set, key, ext);
+ 	if (set->ops == &nft_set_hash_type.ops)
+@@ -50,10 +50,15 @@ bool nft_set_do_lookup(const struct net *net, const struct nft_set *set,
+ 		return nft_rbtree_lookup(net, set, key, ext);
+ 
+ 	WARN_ON_ONCE(1);
++#endif
+ 	return set->ops->lookup(net, set, key, ext);
+ }
++bool nft_set_do_lookup(const struct net *net, const struct nft_set *set,
++		       const u32 *key, const struct nft_set_ext **ext)
++{
++	return __nft_set_do_lookup(net, set, key, ext);
++}
+ EXPORT_SYMBOL_GPL(nft_set_do_lookup);
+-#endif
+ 
+ void nft_lookup_eval(const struct nft_expr *expr,
+ 		     struct nft_regs *regs,
+-- 
+2.47.3
+
-- 
2.47.3



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