netfilter: nf_tables: do not reduce read-only expressions

Skip register tracking for expressions that perform read-only operations
on the registers. Define and use a cookie pointer NFT_REDUCE_READONLY to
avoid defining stubs for these expressions.

This patch re-enables register tracking which was disabled in ed5f85d42290
("netfilter: nf_tables: disable register tracking"). Follow up patches
add remaining register tracking for existing expressions.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

30 files changed, 50 insertions, 1 deletions

diff --git a/net/bridge/netfilter/nft_reject_bridge.c b/net/bridge/netfilter/nft_reject_bridge.c
index fbf858ddec35..71b54fed7263 100644
--- a/net/bridge/netfilter/nft_reject_bridge.c
+++ b/net/bridge/netfilter/nft_reject_bridge.c
@@ -185,6 +185,7 @@ static const struct nft_expr_ops nft_reject_bridge_ops = {
 	.init		= nft_reject_init,
 	.dump		= nft_reject_dump,
 	.validate	= nft_reject_bridge_validate,
+	.reduce		= NFT_REDUCE_READONLY,
 };
 
 static struct nft_expr_type nft_reject_bridge_type __read_mostly = {
diff --git a/net/ipv4/netfilter/nft_dup_ipv4.c b/net/ipv4/netfilter/nft_dup_ipv4.c
index aeb631760eb9..0bcd6aee6000 100644
--- a/net/ipv4/netfilter/nft_dup_ipv4.c
+++ b/net/ipv4/netfilter/nft_dup_ipv4.c
@@ -75,6 +75,7 @@ static const struct nft_expr_ops nft_dup_ipv4_ops = {
 	.eval		= nft_dup_ipv4_eval,
 	.init		= nft_dup_ipv4_init,
 	.dump		= nft_dup_ipv4_dump,
+	.reduce		= NFT_REDUCE_READONLY,
 };
 
 static const struct nla_policy nft_dup_ipv4_policy[NFTA_DUP_MAX + 1] = {
diff --git a/net/ipv4/netfilter/nft_reject_ipv4.c b/net/ipv4/netfilter/nft_reject_ipv4.c
index 55fc23a8f7a7..6cb213bb7256 100644
--- a/net/ipv4/netfilter/nft_reject_ipv4.c
+++ b/net/ipv4/netfilter/nft_reject_ipv4.c
@@ -45,6 +45,7 @@ static const struct nft_expr_ops nft_reject_ipv4_ops = {
 	.init		= nft_reject_init,
 	.dump		= nft_reject_dump,
 	.validate	= nft_reject_validate,
+	.reduce		= NFT_REDUCE_READONLY,
 };
 
 static struct nft_expr_type nft_reject_ipv4_type __read_mostly = {
diff --git a/net/ipv6/netfilter/nft_dup_ipv6.c b/net/ipv6/netfilter/nft_dup_ipv6.c
index 3a00d95e964e..70a405b4006f 100644
--- a/net/ipv6/netfilter/nft_dup_ipv6.c
+++ b/net/ipv6/netfilter/nft_dup_ipv6.c
@@ -73,6 +73,7 @@ static const struct nft_expr_ops nft_dup_ipv6_ops = {
 	.eval		= nft_dup_ipv6_eval,
 	.init		= nft_dup_ipv6_init,
 	.dump		= nft_dup_ipv6_dump,
+	.reduce		= NFT_REDUCE_READONLY,
 };
 
 static const struct nla_policy nft_dup_ipv6_policy[NFTA_DUP_MAX + 1] = {
diff --git a/net/ipv6/netfilter/nft_reject_ipv6.c b/net/ipv6/netfilter/nft_reject_ipv6.c
index ed69c768797e..5c61294f410e 100644
--- a/net/ipv6/netfilter/nft_reject_ipv6.c
+++ b/net/ipv6/netfilter/nft_reject_ipv6.c
@@ -46,6 +46,7 @@ static const struct nft_expr_ops nft_reject_ipv6_ops = {
 	.init		= nft_reject_init,
 	.dump		= nft_reject_dump,
 	.validate	= nft_reject_validate,
+	.reduce		= NFT_REDUCE_READONLY,
 };
 
 static struct nft_expr_type nft_reject_ipv6_type __read_mostly = {
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index e37ac88efa0a..6a10042243eb 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -8290,7 +8290,16 @@ EXPORT_SYMBOL_GPL(nf_tables_trans_destroy_flush_work);
 static bool nft_expr_reduce(struct nft_regs_track *track,
 			    const struct nft_expr *expr)
 {
-	return false;
+	if (!expr->ops->reduce) {
+		pr_warn_once("missing reduce for expression %s ",
+			     expr->ops->type->name);
+		return false;
+	}
+
+	if (nft_reduce_is_readonly(expr))
+		return false;
+
+	return expr->ops->reduce(track, expr);
 }
 
 static int nf_tables_commit_chain_prepare(struct net *net, struct nft_chain *chain)
diff --git a/net/netfilter/nft_cmp.c b/net/netfilter/nft_cmp.c
index 917072af09df..6528f76ca29e 100644
--- a/net/netfilter/nft_cmp.c
+++ b/net/netfilter/nft_cmp.c
@@ -193,6 +193,7 @@ static const struct nft_expr_ops nft_cmp_ops = {
 	.eval		= nft_cmp_eval,
 	.init		= nft_cmp_init,
 	.dump		= nft_cmp_dump,
+	.reduce		= NFT_REDUCE_READONLY,
 	.offload	= nft_cmp_offload,
 };
 
@@ -269,6 +270,7 @@ const struct nft_expr_ops nft_cmp_fast_ops = {
 	.eval		= NULL,	/* inlined */
 	.init		= nft_cmp_fast_init,
 	.dump		= nft_cmp_fast_dump,
+	.reduce		= NFT_REDUCE_READONLY,
 	.offload	= nft_cmp_fast_offload,
 };
 
@@ -359,6 +361,7 @@ const struct nft_expr_ops nft_cmp16_fast_ops = {
 	.eval		= NULL,	/* inlined */
 	.init		= nft_cmp16_fast_init,
 	.dump		= nft_cmp16_fast_dump,
+	.reduce		= NFT_REDUCE_READONLY,
 	.offload	= nft_cmp16_fast_offload,
 };
 
diff --git a/net/netfilter/nft_compat.c b/net/netfilter/nft_compat.c
index 5a46d8289d1d..c16172427622 100644
--- a/net/netfilter/nft_compat.c
+++ b/net/netfilter/nft_compat.c
@@ -871,6 +871,7 @@ nft_target_select_ops(const struct nft_ctx *ctx,
 	ops->dump = nft_target_dump;
 	ops->validate = nft_target_validate;
 	ops->data = target;
+	ops->reduce = NFT_REDUCE_READONLY;
 
 	if (family == NFPROTO_BRIDGE)
 		ops->eval = nft_target_eval_bridge;
diff --git a/net/netfilter/nft_connlimit.c b/net/netfilter/nft_connlimit.c
index 3362417ebfdb..9de1462e4ac4 100644
--- a/net/netfilter/nft_connlimit.c
+++ b/net/netfilter/nft_connlimit.c
@@ -257,6 +257,7 @@ static const struct nft_expr_ops nft_connlimit_ops = {
 	.destroy_clone	= nft_connlimit_destroy_clone,
 	.dump		= nft_connlimit_dump,
 	.gc		= nft_connlimit_gc,
+	.reduce		= NFT_REDUCE_READONLY,
 };
 
 static struct nft_expr_type nft_connlimit_type __read_mostly = {
diff --git a/net/netfilter/nft_counter.c b/net/netfilter/nft_counter.c
index f179e8c3b0ca..da9083605a61 100644
--- a/net/netfilter/nft_counter.c
+++ b/net/netfilter/nft_counter.c
@@ -293,6 +293,7 @@ static const struct nft_expr_ops nft_counter_ops = {
 	.destroy_clone	= nft_counter_destroy,
 	.dump		= nft_counter_dump,
 	.clone		= nft_counter_clone,
+	.reduce		= NFT_REDUCE_READONLY,
 	.offload	= nft_counter_offload,
 	.offload_stats	= nft_counter_offload_stats,
 };
diff --git a/net/netfilter/nft_ct.c b/net/netfilter/nft_ct.c
index 9c7472af9e4a..1ec9a7e96e59 100644
--- a/net/netfilter/nft_ct.c
+++ b/net/netfilter/nft_ct.c
@@ -785,6 +785,7 @@ static const struct nft_expr_ops nft_notrack_ops = {
 	.type		= &nft_notrack_type,
 	.size		= NFT_EXPR_SIZE(0),
 	.eval		= nft_notrack_eval,
+	.reduce		= NFT_REDUCE_READONLY,
 };
 
 static struct nft_expr_type nft_notrack_type __read_mostly = {
diff --git a/net/netfilter/nft_dup_netdev.c b/net/netfilter/nft_dup_netdev.c
index 5b5c607fbf83..63507402716d 100644
--- a/net/netfilter/nft_dup_netdev.c
+++ b/net/netfilter/nft_dup_netdev.c
@@ -79,6 +79,7 @@ static const struct nft_expr_ops nft_dup_netdev_ops = {
 	.eval		= nft_dup_netdev_eval,
 	.init		= nft_dup_netdev_init,
 	.dump		= nft_dup_netdev_dump,
+	.reduce		= NFT_REDUCE_READONLY,
 	.offload	= nft_dup_netdev_offload,
 	.offload_action	= nft_dup_netdev_offload_action,
 };
diff --git a/net/netfilter/nft_dynset.c b/net/netfilter/nft_dynset.c
index 87f3af4645d9..22f70b543fa2 100644
--- a/net/netfilter/nft_dynset.c
+++ b/net/netfilter/nft_dynset.c
@@ -413,6 +413,7 @@ static const struct nft_expr_ops nft_dynset_ops = {
 	.activate	= nft_dynset_activate,
 	.deactivate	= nft_dynset_deactivate,
 	.dump		= nft_dynset_dump,
+	.reduce		= NFT_REDUCE_READONLY,
 };
 
 struct nft_expr_type nft_dynset_type __read_mostly = {
diff --git a/net/netfilter/nft_flow_offload.c b/net/netfilter/nft_flow_offload.c
index 731b5d87ef45..900d48c810a1 100644
--- a/net/netfilter/nft_flow_offload.c
+++ b/net/netfilter/nft_flow_offload.c
@@ -441,6 +441,7 @@ static const struct nft_expr_ops nft_flow_offload_ops = {
 	.destroy	= nft_flow_offload_destroy,
 	.validate	= nft_flow_offload_validate,
 	.dump		= nft_flow_offload_dump,
+	.reduce		= NFT_REDUCE_READONLY,
 };
 
 static struct nft_expr_type nft_flow_offload_type __read_mostly = {
diff --git a/net/netfilter/nft_fwd_netdev.c b/net/netfilter/nft_fwd_netdev.c
index 08e7a289738e..7c5876dc9ff2 100644
--- a/net/netfilter/nft_fwd_netdev.c
+++ b/net/netfilter/nft_fwd_netdev.c
@@ -217,6 +217,7 @@ static const struct nft_expr_ops nft_fwd_neigh_netdev_ops = {
 	.init		= nft_fwd_neigh_init,
 	.dump		= nft_fwd_neigh_dump,
 	.validate	= nft_fwd_validate,
+	.reduce		= NFT_REDUCE_READONLY,
 };
 
 static const struct nft_expr_ops nft_fwd_netdev_ops = {
@@ -226,6 +227,7 @@ static const struct nft_expr_ops nft_fwd_netdev_ops = {
 	.init		= nft_fwd_netdev_init,
 	.dump		= nft_fwd_netdev_dump,
 	.validate	= nft_fwd_validate,
+	.reduce		= NFT_REDUCE_READONLY,
 	.offload	= nft_fwd_netdev_offload,
 	.offload_action	= nft_fwd_netdev_offload_action,
 };
diff --git a/net/netfilter/nft_last.c b/net/netfilter/nft_last.c
index 4f745a409d34..43d0d4aadb1f 100644
--- a/net/netfilter/nft_last.c
+++ b/net/netfilter/nft_last.c
@@ -120,6 +120,7 @@ static const struct nft_expr_ops nft_last_ops = {
 	.destroy	= nft_last_destroy,
 	.clone		= nft_last_clone,
 	.dump		= nft_last_dump,
+	.reduce		= NFT_REDUCE_READONLY,
 };
 
 struct nft_expr_type nft_last_type __read_mostly = {
diff --git a/net/netfilter/nft_limit.c b/net/netfilter/nft_limit.c
index a726b623963d..d4a6cf3cd697 100644
--- a/net/netfilter/nft_limit.c
+++ b/net/netfilter/nft_limit.c
@@ -225,6 +225,7 @@ static const struct nft_expr_ops nft_limit_pkts_ops = {
 	.destroy	= nft_limit_pkts_destroy,
 	.clone		= nft_limit_pkts_clone,
 	.dump		= nft_limit_pkts_dump,
+	.reduce		= NFT_REDUCE_READONLY,
 };
 
 static void nft_limit_bytes_eval(const struct nft_expr *expr,
@@ -279,6 +280,7 @@ static const struct nft_expr_ops nft_limit_bytes_ops = {
 	.dump		= nft_limit_bytes_dump,
 	.clone		= nft_limit_bytes_clone,
 	.destroy	= nft_limit_bytes_destroy,
+	.reduce		= NFT_REDUCE_READONLY,
 };
 
 static const struct nft_expr_ops *
diff --git a/net/netfilter/nft_log.c b/net/netfilter/nft_log.c
index 54f6c2035e84..0e13c003f0c1 100644
--- a/net/netfilter/nft_log.c
+++ b/net/netfilter/nft_log.c
@@ -290,6 +290,7 @@ static const struct nft_expr_ops nft_log_ops = {
 	.init		= nft_log_init,
 	.destroy	= nft_log_destroy,
 	.dump		= nft_log_dump,
+	.reduce		= NFT_REDUCE_READONLY,
 };
 
 static struct nft_expr_type nft_log_type __read_mostly = {
diff --git a/net/netfilter/nft_masq.c b/net/netfilter/nft_masq.c
index 9953e8053753..2a0adc497bbb 100644
--- a/net/netfilter/nft_masq.c
+++ b/net/netfilter/nft_masq.c
@@ -129,6 +129,7 @@ static const struct nft_expr_ops nft_masq_ipv4_ops = {
 	.destroy	= nft_masq_ipv4_destroy,
 	.dump		= nft_masq_dump,
 	.validate	= nft_masq_validate,
+	.reduce		= NFT_REDUCE_READONLY,
 };
 
 static struct nft_expr_type nft_masq_ipv4_type __read_mostly = {
@@ -175,6 +176,7 @@ static const struct nft_expr_ops nft_masq_ipv6_ops = {
 	.destroy	= nft_masq_ipv6_destroy,
 	.dump		= nft_masq_dump,
 	.validate	= nft_masq_validate,
+	.reduce		= NFT_REDUCE_READONLY,
 };
 
 static struct nft_expr_type nft_masq_ipv6_type __read_mostly = {
@@ -230,6 +232,7 @@ static const struct nft_expr_ops nft_masq_inet_ops = {
 	.destroy	= nft_masq_inet_destroy,
 	.dump		= nft_masq_dump,
 	.validate	= nft_masq_validate,
+	.reduce		= NFT_REDUCE_READONLY,
 };
 
 static struct nft_expr_type nft_masq_inet_type __read_mostly = {
diff --git a/net/netfilter/nft_nat.c b/net/netfilter/nft_nat.c
index be1595d6979d..4394df4bc99b 100644
--- a/net/netfilter/nft_nat.c
+++ b/net/netfilter/nft_nat.c
@@ -317,6 +317,7 @@ static const struct nft_expr_ops nft_nat_ops = {
 	.destroy        = nft_nat_destroy,
 	.dump           = nft_nat_dump,
 	.validate	= nft_nat_validate,
+	.reduce		= NFT_REDUCE_READONLY,
 };
 
 static struct nft_expr_type nft_nat_type __read_mostly = {
@@ -346,6 +347,7 @@ static const struct nft_expr_ops nft_nat_inet_ops = {
 	.destroy        = nft_nat_destroy,
 	.dump           = nft_nat_dump,
 	.validate	= nft_nat_validate,
+	.reduce		= NFT_REDUCE_READONLY,
 };
 
 static struct nft_expr_type nft_inet_nat_type __read_mostly = {
diff --git a/net/netfilter/nft_objref.c b/net/netfilter/nft_objref.c
index 94b2327e71dc..5d8d91b3904d 100644
--- a/net/netfilter/nft_objref.c
+++ b/net/netfilter/nft_objref.c
@@ -91,6 +91,7 @@ static const struct nft_expr_ops nft_objref_ops = {
 	.activate	= nft_objref_activate,
 	.deactivate	= nft_objref_deactivate,
 	.dump		= nft_objref_dump,
+	.reduce		= NFT_REDUCE_READONLY,
 };
 
 struct nft_objref_map {
@@ -204,6 +205,7 @@ static const struct nft_expr_ops nft_objref_map_ops = {
 	.deactivate	= nft_objref_map_deactivate,
 	.destroy	= nft_objref_map_destroy,
 	.dump		= nft_objref_map_dump,
+	.reduce		= NFT_REDUCE_READONLY,
 };
 
 static const struct nft_expr_ops *
diff --git a/net/netfilter/nft_queue.c b/net/netfilter/nft_queue.c
index 9ba1de51ac07..15e4b7640dc0 100644
--- a/net/netfilter/nft_queue.c
+++ b/net/netfilter/nft_queue.c
@@ -164,6 +164,7 @@ static const struct nft_expr_ops nft_queue_ops = {
 	.eval		= nft_queue_eval,
 	.init		= nft_queue_init,
 	.dump		= nft_queue_dump,
+	.reduce		= NFT_REDUCE_READONLY,
 };
 
 static const struct nft_expr_ops nft_queue_sreg_ops = {
@@ -172,6 +173,7 @@ static const struct nft_expr_ops nft_queue_sreg_ops = {
 	.eval		= nft_queue_sreg_eval,
 	.init		= nft_queue_sreg_init,
 	.dump		= nft_queue_sreg_dump,
+	.reduce		= NFT_REDUCE_READONLY,
 };
 
 static const struct nft_expr_ops *
diff --git a/net/netfilter/nft_quota.c b/net/netfilter/nft_quota.c
index f394a0b562f6..d7db57ed3bc1 100644
--- a/net/netfilter/nft_quota.c
+++ b/net/netfilter/nft_quota.c
@@ -254,6 +254,7 @@ static const struct nft_expr_ops nft_quota_ops = {
 	.destroy	= nft_quota_destroy,
 	.clone		= nft_quota_clone,
 	.dump		= nft_quota_dump,
+	.reduce		= NFT_REDUCE_READONLY,
 };
 
 static struct nft_expr_type nft_quota_type __read_mostly = {
diff --git a/net/netfilter/nft_range.c b/net/netfilter/nft_range.c
index e4a1c44d7f51..66f77484c227 100644
--- a/net/netfilter/nft_range.c
+++ b/net/netfilter/nft_range.c
@@ -140,6 +140,7 @@ static const struct nft_expr_ops nft_range_ops = {
 	.eval		= nft_range_eval,
 	.init		= nft_range_init,
 	.dump		= nft_range_dump,
+	.reduce		= NFT_REDUCE_READONLY,
 };
 
 struct nft_expr_type nft_range_type __read_mostly = {
diff --git a/net/netfilter/nft_redir.c b/net/netfilter/nft_redir.c
index ba09890dddb5..5086adfe731c 100644
--- a/net/netfilter/nft_redir.c
+++ b/net/netfilter/nft_redir.c
@@ -134,6 +134,7 @@ static const struct nft_expr_ops nft_redir_ipv4_ops = {
 	.destroy	= nft_redir_ipv4_destroy,
 	.dump		= nft_redir_dump,
 	.validate	= nft_redir_validate,
+	.reduce		= NFT_REDUCE_READONLY,
 };
 
 static struct nft_expr_type nft_redir_ipv4_type __read_mostly = {
@@ -183,6 +184,7 @@ static const struct nft_expr_ops nft_redir_ipv6_ops = {
 	.destroy	= nft_redir_ipv6_destroy,
 	.dump		= nft_redir_dump,
 	.validate	= nft_redir_validate,
+	.reduce		= NFT_REDUCE_READONLY,
 };
 
 static struct nft_expr_type nft_redir_ipv6_type __read_mostly = {
@@ -225,6 +227,7 @@ static const struct nft_expr_ops nft_redir_inet_ops = {
 	.destroy	= nft_redir_inet_destroy,
 	.dump		= nft_redir_dump,
 	.validate	= nft_redir_validate,
+	.reduce		= NFT_REDUCE_READONLY,
 };
 
 static struct nft_expr_type nft_redir_inet_type __read_mostly = {
diff --git a/net/netfilter/nft_reject_inet.c b/net/netfilter/nft_reject_inet.c
index 554caf967baa..973fa31a9dd6 100644
--- a/net/netfilter/nft_reject_inet.c
+++ b/net/netfilter/nft_reject_inet.c
@@ -80,6 +80,7 @@ static const struct nft_expr_ops nft_reject_inet_ops = {
 	.init		= nft_reject_init,
 	.dump		= nft_reject_dump,
 	.validate	= nft_reject_inet_validate,
+	.reduce		= NFT_REDUCE_READONLY,
 };
 
 static struct nft_expr_type nft_reject_inet_type __read_mostly = {
diff --git a/net/netfilter/nft_reject_netdev.c b/net/netfilter/nft_reject_netdev.c
index 61cd8c4ac385..7865cd8b11bb 100644
--- a/net/netfilter/nft_reject_netdev.c
+++ b/net/netfilter/nft_reject_netdev.c
@@ -159,6 +159,7 @@ static const struct nft_expr_ops nft_reject_netdev_ops = {
 	.init		= nft_reject_init,
 	.dump		= nft_reject_dump,
 	.validate	= nft_reject_netdev_validate,
+	.reduce		= NFT_REDUCE_READONLY,
 };
 
 static struct nft_expr_type nft_reject_netdev_type __read_mostly = {
diff --git a/net/netfilter/nft_rt.c b/net/netfilter/nft_rt.c
index bcd01a63e38f..71931ec91721 100644
--- a/net/netfilter/nft_rt.c
+++ b/net/netfilter/nft_rt.c
@@ -191,6 +191,7 @@ static const struct nft_expr_ops nft_rt_get_ops = {
 	.init		= nft_rt_get_init,
 	.dump		= nft_rt_get_dump,
 	.validate	= nft_rt_validate,
+	.reduce		= NFT_REDUCE_READONLY,
 };
 
 struct nft_expr_type nft_rt_type __read_mostly = {
diff --git a/net/netfilter/nft_synproxy.c b/net/netfilter/nft_synproxy.c
index 1133e06f3c40..6cf9a04fbfe2 100644
--- a/net/netfilter/nft_synproxy.c
+++ b/net/netfilter/nft_synproxy.c
@@ -288,6 +288,7 @@ static const struct nft_expr_ops nft_synproxy_ops = {
 	.dump		= nft_synproxy_dump,
 	.type		= &nft_synproxy_type,
 	.validate	= nft_synproxy_validate,
+	.reduce		= NFT_REDUCE_READONLY,
 };
 
 static struct nft_expr_type nft_synproxy_type __read_mostly = {
diff --git a/net/netfilter/nft_tproxy.c b/net/netfilter/nft_tproxy.c
index b5b09a902c7a..801f013971df 100644
--- a/net/netfilter/nft_tproxy.c
+++ b/net/netfilter/nft_tproxy.c
@@ -320,6 +320,7 @@ static const struct nft_expr_ops nft_tproxy_ops = {
 	.init		= nft_tproxy_init,
 	.destroy	= nft_tproxy_destroy,
 	.dump		= nft_tproxy_dump,
+	.reduce		= NFT_REDUCE_READONLY,
 };
 
 static struct nft_expr_type nft_tproxy_type __read_mostly = {