netdev - [PATCH net] netfilter: nf_tables: Fix memory leak in nf_tables

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Message-Id: <20251224124826.189013-1-zilin@seu.edu.cn>
Date: Wed, 24 Dec 2025 12:48:26 +0000
From: Zilin Guan <zilin@....edu.cn>
To: pablo@...filter.org
Cc: fw@...len.de,
	phil@....cc,
	davem@...emloft.net,
	edumazet@...gle.com,
	kuba@...nel.org,
	pabeni@...hat.com,
	horms@...nel.org,
	netfilter-devel@...r.kernel.org,
	coreteam@...filter.org,
	netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Zilin Guan <zilin@....edu.cn>
Subject: [PATCH net] netfilter: nf_tables: Fix memory leak in nf_tables_newrule()

In nf_tables_newrule(), if nft_use_inc() fails, the function jumps to
the err_release_rule label without freeing the allocated flow, leading
to a memory leak.

Fix this by adding a new label err_destroy_flow and jumping to it when
nft_use_inc() fails. This ensures that the flow is properly released
in this error case.

Fixes: 1689f25924ada ("netfilter: nf_tables: report use refcount overflow")
Signed-off-by: Zilin Guan <zilin@....edu.cn>
---
 net/netfilter/nf_tables_api.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 618af6e90773..729a92781a1a 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -4439,7 +4439,7 @@ static int nf_tables_newrule(struct sk_buff *skb, const struct nfnl_info *info,
 
 	if (!nft_use_inc(&chain->use)) {
 		err = -EMFILE;
-		goto err_release_rule;
+		goto err_destroy_flow;
 	}
 
 	if (info->nlh->nlmsg_flags & NLM_F_REPLACE) {
@@ -4489,6 +4489,7 @@ static int nf_tables_newrule(struct sk_buff *skb, const struct nfnl_info *info,
 
 err_destroy_flow_rule:
 	nft_use_dec_restore(&chain->use);
+err_destroy_flow:
 	if (flow)
 		nft_flow_rule_destroy(flow);
 err_release_rule:
-- 
2.34.1