netdev - [PATCH net 03/17] netfilter: nf_tables: possible module reference underflow in error path

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Date:   Wed, 17 Aug 2022 16:00:01 +0200
From:   Florian Westphal <fw@...len.de>
To:     netdev@...r.kernel.org
Cc:     <netfilter-devel@...r.kernel.org>,
        Pablo Neira Ayuso <pablo@...filter.org>,
        Paolo Abeni <pabeni@...hat.com>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>
Subject: [PATCH net 03/17] netfilter: nf_tables: possible module reference underflow in error path

From: Pablo Neira Ayuso <pablo@...filter.org>

dst->ops is set on when nft_expr_clone() fails, but module refcount has
not been bumped yet, therefore nft_expr_destroy() leads to module
reference underflow.

Fixes: 8cfd9b0f8515 ("netfilter: nftables: generalize set expressions support")
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
---
 net/netfilter/nf_tables_api.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index ac549c5b88c2..989c9782ecc3 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -5601,7 +5601,7 @@ int nft_set_elem_expr_clone(const struct nft_ctx *ctx, struct nft_set *set,
 
 		err = nft_expr_clone(expr, set->exprs[i]);
 		if (err < 0) {
-			nft_expr_destroy(ctx, expr);
+			kfree(expr);
 			goto err_expr;
 		}
 		expr_array[i] = expr;
-- 
2.35.1