From: Florian Westphal <fw@strlen.de>
To: <netdev@vger.kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>,
<netfilter-devel@vger.kernel.org>,
pablo@netfilter.org
Subject: [PATCH net 2/3] netfilter: nft_connlimit: fix possible data race on connection count
Date: Wed, 29 Oct 2025 14:56:16 +0100 [thread overview]
Message-ID: <20251029135617.18274-3-fw@strlen.de> (raw)
In-Reply-To: <20251029135617.18274-1-fw@strlen.de>
From: Fernando Fernandez Mancera <fmancera@suse.de>
nft_connlimit_eval() reads priv->list->count to check if the connection
limit has been exceeded. This value is being read without a lock and can
be modified by a different process. Use READ_ONCE() for correctness.
Fixes: df4a90250976 ("netfilter: nf_conncount: merge lookup and add functions")
Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
Signed-off-by: Florian Westphal <fw@strlen.de>
---
net/netfilter/nft_connlimit.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/netfilter/nft_connlimit.c b/net/netfilter/nft_connlimit.c
index 92b984fa8175..fc35a11cdca2 100644
--- a/net/netfilter/nft_connlimit.c
+++ b/net/netfilter/nft_connlimit.c
@@ -48,7 +48,7 @@ static inline void nft_connlimit_do_eval(struct nft_connlimit *priv,
return;
}
- count = priv->list->count;
+ count = READ_ONCE(priv->list->count);
if ((count > priv->limit) ^ priv->invert) {
regs->verdict.code = NFT_BREAK;
--
2.51.0
next prev parent reply other threads:[~2025-10-29 13:56 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-29 13:56 [PATCH net 0/3] netfilter: updates for net Florian Westphal
2025-10-29 13:56 ` [PATCH net 1/3] netfilter: nft_ct: enable labels for get case too Florian Westphal
2025-10-30 1:40 ` patchwork-bot+netdevbpf
2025-10-29 13:56 ` Florian Westphal [this message]
2025-10-29 13:56 ` [PATCH net 3/3] netfilter: nft_ct: add seqadj extension for natted connections Florian Westphal
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