netfilter: nf_tables_offload: incorrect flow offload action array size

commit b1a5983f56e371046dcf164f90bfaf704d2b89f6 upstream.

immediate verdict expression needs to allocate one slot in the flow offload
action array, however, immediate data expression does not need to do so.

fwd and dup expression need to allocate one slot, this is missing.

Add a new offload_action interface to report if this expression needs to
allocate one slot in the flow offload action array.

Fixes: be2861dc36d7 ("netfilter: nft_{fwd,dup}_netdev: add offload support")
Reported-and-tested-by: Nick Gregory <Nick.Gregory@Sophos.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

4 files changed, 25 insertions, 2 deletions

diff --git a/net/netfilter/nf_tables_offload.c b/net/netfilter/nf_tables_offload.c
index e5fcbb0e4b8e..839fd09f1bb4 100644
--- a/net/netfilter/nf_tables_offload.c
+++ b/net/netfilter/nf_tables_offload.c
@@ -94,7 +94,8 @@ struct nft_flow_rule *nft_flow_rule_create(struct net *net,
 
 	expr = nft_expr_first(rule);
 	while (nft_expr_more(rule, expr)) {
-		if (expr->ops->offload_flags & NFT_OFFLOAD_F_ACTION)
+		if (expr->ops->offload_action &&
+		    expr->ops->offload_action(expr))
 			num_actions++;
 
 		expr = nft_expr_next(expr);
diff --git a/net/netfilter/nft_dup_netdev.c b/net/netfilter/nft_dup_netdev.c
index 40788b3f1071..70c457476b87 100644
--- a/net/netfilter/nft_dup_netdev.c
+++ b/net/netfilter/nft_dup_netdev.c
@@ -67,6 +67,11 @@ static int nft_dup_netdev_offload(struct nft_offload_ctx *ctx,
 	return nft_fwd_dup_netdev_offload(ctx, flow, FLOW_ACTION_MIRRED, oif);
 }
 
+static bool nft_dup_netdev_offload_action(const struct nft_expr *expr)
+{
+	return true;
+}
+
 static struct nft_expr_type nft_dup_netdev_type;
 static const struct nft_expr_ops nft_dup_netdev_ops = {
 	.type		= &nft_dup_netdev_type,
@@ -75,6 +80,7 @@ static const struct nft_expr_ops nft_dup_netdev_ops = {
 	.init		= nft_dup_netdev_init,
 	.dump		= nft_dup_netdev_dump,
 	.offload	= nft_dup_netdev_offload,
+	.offload_action	= nft_dup_netdev_offload_action,
 };
 
 static struct nft_expr_type nft_dup_netdev_type __read_mostly = {
diff --git a/net/netfilter/nft_fwd_netdev.c b/net/netfilter/nft_fwd_netdev.c
index b77985986b24..3b0dcd170551 100644
--- a/net/netfilter/nft_fwd_netdev.c
+++ b/net/netfilter/nft_fwd_netdev.c
@@ -77,6 +77,11 @@ static int nft_fwd_netdev_offload(struct nft_offload_ctx *ctx,
 	return nft_fwd_dup_netdev_offload(ctx, flow, FLOW_ACTION_REDIRECT, oif);
 }
 
+static bool nft_fwd_netdev_offload_action(const struct nft_expr *expr)
+{
+	return true;
+}
+
 struct nft_fwd_neigh {
 	enum nft_registers	sreg_dev:8;
 	enum nft_registers	sreg_addr:8;
@@ -219,6 +224,7 @@ static const struct nft_expr_ops nft_fwd_netdev_ops = {
 	.dump		= nft_fwd_netdev_dump,
 	.validate	= nft_fwd_validate,
 	.offload	= nft_fwd_netdev_offload,
+	.offload_action	= nft_fwd_netdev_offload_action,
 };
 
 static const struct nft_expr_ops *
diff --git a/net/netfilter/nft_immediate.c b/net/netfilter/nft_immediate.c
index c63eb3b17178..5c9d88560a47 100644
--- a/net/netfilter/nft_immediate.c
+++ b/net/netfilter/nft_immediate.c
@@ -213,6 +213,16 @@ static int nft_immediate_offload(struct nft_offload_ctx *ctx,
 	return 0;
 }
 
+static bool nft_immediate_offload_action(const struct nft_expr *expr)
+{
+	const struct nft_immediate_expr *priv = nft_expr_priv(expr);
+
+	if (priv->dreg == NFT_REG_VERDICT)
+		return true;
+
+	return false;
+}
+
 static const struct nft_expr_ops nft_imm_ops = {
 	.type		= &nft_imm_type,
 	.size		= NFT_EXPR_SIZE(sizeof(struct nft_immediate_expr)),
@@ -224,7 +234,7 @@ static const struct nft_expr_ops nft_imm_ops = {
 	.dump		= nft_immediate_dump,
 	.validate	= nft_immediate_validate,
 	.offload	= nft_immediate_offload,
-	.offload_flags	= NFT_OFFLOAD_F_ACTION,
+	.offload_action	= nft_immediate_offload_action,
 };
 
 struct nft_expr_type nft_imm_type __read_mostly = {