netfilter pull request nf-25-12-16

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Merge tag 'nf-25-12-16' of https://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf

Florian Westphal says:

====================
netfilter: updates for net

The following patchset contains Netfilter fixes for *net*:

1)  Jozsef Kadlecsik is retiring.  Fortunately Jozsef will still keep an
    eye on ipset patches.

2)  remove a bogus direction check from nat core, this caused spurious
    flakes in the 'reverse clash' selftest, from myself.

3) nf_tables doesn't need to do chain validation on register store,
   from Pablo Neira Ayuso.

4) nf_tables shouldn't revisit chains during ruleset (graph) validation
   if possible.  Both 3 and 4 were slated for -next initially but there
   are now two independent reports of people hitting soft lockup errors
   during ruleset validation, so it makes no sense anymore to route
   this via -next given this is -stable material. From myself.

5) call cond_resched() in a more frequently visited place during nf_tables
   chain validation, this wasn't possible earlier due to rcu read lock,
   but nowadays its not held anymore during set walks.

6) Don't fail conntrack packetdrill test with HZ=100 kernels.

netfilter pull request nf-25-12-16

* tag 'nf-25-12-16' of https://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf:
  selftests: netfilter: packetdrill: avoid failure on HZ=100 kernel
  netfilter: nf_tables: avoid softlockup warnings in nft_chain_validate
  netfilter: nf_tables: avoid chain re-validation if possible
  netfilter: nf_tables: remove redundant chain validation on register store
  netfilter: nf_nat: remove bogus direction check
  MAINTAINERS: Remove Jozsef Kadlecsik from MAINTAINERS file
====================

Link: https://patch.msgid.link/20251216190904.14507-1-fw@strlen.de
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

CREDITS

@@ -1983,6 +1983,7 @@ D: netfilter: TCP window tracking code
 D: netfilter: raw table
 D: netfilter: iprange match
 D: netfilter: new logging interfaces
+D: netfilter: ipset
 D: netfilter: various other hacks
 S: Tata
 S: Hungary

MAINTAINERS

@@ -17808,7 +17808,6 @@ F:	drivers/net/ethernet/neterion/
 
 NETFILTER
 M:	Pablo Neira Ayuso <pablo@netfilter.org>
-M:	Jozsef Kadlecsik <kadlec@netfilter.org>
 M:	Florian Westphal <fw@strlen.de>
 R:	Phil Sutter <phil@nwl.cc>
 L:	netfilter-devel@vger.kernel.org

include/net/netfilter/nf_tables.h

@@ -1091,6 +1091,29 @@ struct nft_rule_blob {
 		__attribute__((aligned(__alignof__(struct nft_rule_dp))));
 };
 
+enum nft_chain_types {
+	NFT_CHAIN_T_DEFAULT = 0,
+	NFT_CHAIN_T_ROUTE,
+	NFT_CHAIN_T_NAT,
+	NFT_CHAIN_T_MAX
+};
+
+/**
+ *	struct nft_chain_validate_state - validation state
+ *
+ *	If a chain is encountered again during table validation it is
+ *	possible to avoid revalidation provided the calling context is
+ *	compatible.  This structure stores relevant calling context of
+ *	previous validations.
+ *
+ *	@hook_mask: the hook numbers and locations the chain is linked to
+ *	@depth: the deepest call chain level the chain is linked to
+ */
+struct nft_chain_validate_state {
+	u8			hook_mask[NFT_CHAIN_T_MAX];
+	u8			depth;
+};
+
 /**
  *	struct nft_chain - nf_tables chain
  *
@@ -1109,6 +1132,7 @@ struct nft_rule_blob {
  *	@udlen: user data length
  *	@udata: user data in the chain
  *	@blob_next: rule blob pointer to the next in the chain
+ *	@vstate: validation state
  */
 struct nft_chain {
 	struct nft_rule_blob		__rcu *blob_gen_0;
@@ -1128,9 +1152,10 @@ struct nft_chain {
 
 	/* Only used during control plane commit phase: */
 	struct nft_rule_blob		*blob_next;
+	struct nft_chain_validate_state vstate;
 };
 
-int nft_chain_validate(const struct nft_ctx *ctx, const struct nft_chain *chain);
+int nft_chain_validate(const struct nft_ctx *ctx, struct nft_chain *chain);
 int nft_setelem_validate(const struct nft_ctx *ctx, struct nft_set *set,
 			 const struct nft_set_iter *iter,
 			 struct nft_elem_priv *elem_priv);
@@ -1138,13 +1163,6 @@ int nft_set_catchall_validate(const struct nft_ctx *ctx, struct nft_set *set);
 int nf_tables_bind_chain(const struct nft_ctx *ctx, struct nft_chain *chain);
 void nf_tables_unbind_chain(const struct nft_ctx *ctx, struct nft_chain *chain);
 
-enum nft_chain_types {
-	NFT_CHAIN_T_DEFAULT = 0,
-	NFT_CHAIN_T_ROUTE,
-	NFT_CHAIN_T_NAT,
-	NFT_CHAIN_T_MAX
-};
-
 /**
  * 	struct nft_chain_type - nf_tables chain type info
  *

net/netfilter/nf_nat_core.c

@@ -294,25 +294,13 @@ nf_nat_used_tuple_new(const struct nf_conntrack_tuple *tuple,
 
 	ct = nf_ct_tuplehash_to_ctrack(thash);
 
-	/* NB: IP_CT_DIR_ORIGINAL should be impossible because
-	 * nf_nat_used_tuple() handles origin collisions.
-	 *
-	 * Handle remote chance other CPU confirmed its ct right after.
-	 */
-	if (thash->tuple.dst.dir != IP_CT_DIR_REPLY)
-		goto out;
-
 	/* clashing connection subject to NAT? Retry with new tuple. */
 	if (READ_ONCE(ct->status) & uses_nat)
 		goto out;
 
 	if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
-			      &ignored_ct->tuplehash[IP_CT_DIR_REPLY].tuple) &&
-	    nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
-			      &ignored_ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple)) {
+			      &ignored_ct->tuplehash[IP_CT_DIR_REPLY].tuple))
 		taken = false;
-		goto out;
-	}
 out:
 	nf_ct_put(ct);
 	return taken;

net/netfilter/nf_tables_api.c

@@ -123,6 +123,29 @@ static void nft_validate_state_update(struct nft_table *table, u8 new_validate_s
 
 	table->validate_state = new_validate_state;
 }
+
+static bool nft_chain_vstate_valid(const struct nft_ctx *ctx,
+				   const struct nft_chain *chain)
+{
+	const struct nft_base_chain *base_chain;
+	enum nft_chain_types type;
+	u8 hooknum;
+
+	if (WARN_ON_ONCE(!nft_is_base_chain(ctx->chain)))
+		return false;
+
+	base_chain = nft_base_chain(ctx->chain);
+	hooknum = base_chain->ops.hooknum;
+	type = base_chain->type->type;
+
+	/* chain is already validated for this call depth */
+	if (chain->vstate.depth >= ctx->level &&
+	    chain->vstate.hook_mask[type] & BIT(hooknum))
+		return true;
+
+	return false;
+}
+
 static void nf_tables_trans_destroy_work(struct work_struct *w);
 
 static void nft_trans_gc_work(struct work_struct *work);
@@ -4079,6 +4102,29 @@ static void nf_tables_rule_release(const struct nft_ctx *ctx, struct nft_rule *r
 	nf_tables_rule_destroy(ctx, rule);
 }
 
+static void nft_chain_vstate_update(const struct nft_ctx *ctx, struct nft_chain *chain)
+{
+	const struct nft_base_chain *base_chain;
+	enum nft_chain_types type;
+	u8 hooknum;
+
+	/* ctx->chain must hold the calling base chain. */
+	if (WARN_ON_ONCE(!nft_is_base_chain(ctx->chain))) {
+		memset(&chain->vstate, 0, sizeof(chain->vstate));
+		return;
+	}
+
+	base_chain = nft_base_chain(ctx->chain);
+	hooknum = base_chain->ops.hooknum;
+	type = base_chain->type->type;
+
+	BUILD_BUG_ON(BIT(NF_INET_NUMHOOKS) > U8_MAX);
+
+	chain->vstate.hook_mask[type] |= BIT(hooknum);
+	if (chain->vstate.depth < ctx->level)
+		chain->vstate.depth = ctx->level;
+}
+
 /** nft_chain_validate - loop detection and hook validation
  *
  * @ctx: context containing call depth and base chain
@@ -4088,15 +4134,25 @@ static void nf_tables_rule_release(const struct nft_ctx *ctx, struct nft_rule *r
  * and set lookups until either the jump limit is hit or all reachable
  * chains have been validated.
  */
-int nft_chain_validate(const struct nft_ctx *ctx, const struct nft_chain *chain)
+int nft_chain_validate(const struct nft_ctx *ctx, struct nft_chain *chain)
 {
 	struct nft_expr *expr, *last;
 	struct nft_rule *rule;
 	int err;
 
+	BUILD_BUG_ON(NFT_JUMP_STACK_SIZE > 255);
 	if (ctx->level == NFT_JUMP_STACK_SIZE)
 		return -EMLINK;
 
+	if (ctx->level > 0) {
+		/* jumps to base chains are not allowed. */
+		if (nft_is_base_chain(chain))
+			return -ELOOP;
+
+		if (nft_chain_vstate_valid(ctx, chain))
+			return 0;
+	}
+
 	list_for_each_entry(rule, &chain->rules, list) {
 		if (fatal_signal_pending(current))
 			return -EINTR;
@@ -4115,8 +4171,11 @@ int nft_chain_validate(const struct nft_ctx *ctx, const struct nft_chain *chain)
 			if (err < 0)
 				return err;
 		}
+
+		cond_resched();
 	}
 
+	nft_chain_vstate_update(ctx, chain);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(nft_chain_validate);
@@ -4128,7 +4187,7 @@ static int nft_table_validate(struct net *net, const struct nft_table *table)
 		.net	= net,
 		.family	= table->family,
 	};
-	int err;
+	int err = 0;
 
 	list_for_each_entry(chain, &table->chains, list) {
 		if (!nft_is_base_chain(chain))
@@ -4137,12 +4196,14 @@ static int nft_table_validate(struct net *net, const struct nft_table *table)
 		ctx.chain = chain;
 		err = nft_chain_validate(&ctx, chain);
 		if (err < 0)
-			return err;
-
-		cond_resched();
+			goto err;
 	}
 
-	return 0;
+err:
+	list_for_each_entry(chain, &table->chains, list)
+		memset(&chain->vstate, 0, sizeof(chain->vstate));
+
+	return err;
 }
 
 int nft_setelem_validate(const struct nft_ctx *ctx, struct nft_set *set,
@@ -11676,21 +11737,10 @@ static int nft_validate_register_store(const struct nft_ctx *ctx,
 				       enum nft_data_types type,
 				       unsigned int len)
 {
-	int err;
-
 	switch (reg) {
 	case NFT_REG_VERDICT:
 		if (type != NFT_DATA_VERDICT)
 			return -EINVAL;
-
-		if (data != NULL &&
-		    (data->verdict.code == NFT_GOTO ||
-		     data->verdict.code == NFT_JUMP)) {
-			err = nft_chain_validate(ctx, data->verdict.chain);
-			if (err < 0)
-				return err;
-		}
-
 		break;
 	default:
 		if (type != NFT_DATA_VALUE)

tools/testing/selftests/net/netfilter/conntrack_reverse_clash.c

@@ -33,9 +33,14 @@ static void die(const char *e)
 	exit(111);
 }
 
-static void die_port(uint16_t got, uint16_t want)
+static void die_port(const struct sockaddr_in *sin, uint16_t want)
 {
-	fprintf(stderr, "Port number changed, wanted %d got %d\n", want, ntohs(got));
+	uint16_t got = ntohs(sin->sin_port);
+	char str[INET_ADDRSTRLEN];
+
+	inet_ntop(AF_INET, &sin->sin_addr, str, sizeof(str));
+
+	fprintf(stderr, "Port number changed, wanted %d got %d from %s\n", want, got, str);
 	exit(1);
 }
 
@@ -100,7 +105,7 @@ int main(int argc, char *argv[])
 				die("child recvfrom");
 
 			if (peer.sin_port != htons(PORT))
-				die_port(peer.sin_port, PORT);
+				die_port(&peer, PORT);
 		} else {
 			if (sendto(s2, buf, LEN, 0, (struct sockaddr *)&sa1, sizeof(sa1)) != LEN)
 				continue;
@@ -109,7 +114,7 @@ int main(int argc, char *argv[])
 				die("parent recvfrom");
 
 			if (peer.sin_port != htons((PORT + 1)))
-				die_port(peer.sin_port, PORT + 1);
+				die_port(&peer, PORT + 1);
 		}
 	}
 

tools/testing/selftests/net/netfilter/conntrack_reverse_clash.sh

@@ -45,6 +45,8 @@ if ip netns exec "$ns0" ./conntrack_reverse_clash; then
 	echo "PASS: No SNAT performed for null bindings"
 else
 	echo "ERROR: SNAT performed without any matching snat rule"
+	ip netns exec "$ns0" conntrack -L
+	ip netns exec "$ns0" conntrack -S
 	exit 1
 fi
 

tools/testing/selftests/net/netfilter/packetdrill/conntrack_syn_challenge_ack.pkt

@@ -26,7 +26,7 @@
 
 +0.01 > R 643160523:643160523(0) win 0
 
-+0.01 `conntrack -f $NFCT_IP_VERSION -L -p tcp --dport 8080 2>/dev/null | grep UNREPLIED | grep -q SYN_SENT`
++0.1 `conntrack -f $NFCT_IP_VERSION -L -p tcp --dport 8080 2>/dev/null | grep UNREPLIED | grep -q SYN_SENT`
 
 // Must go through.
 +0.01 > S 0:0(0) win 65535 <mss 1460,sackOK,TS val 1 ecr 0,nop,wscale 8>