From nobody Mon Jun 8 16:31:17 2026 Received: from cstnet.cn (smtp81.cstnet.cn [159.226.251.81]) (using TLSv1.2 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 22B033403F5; Thu, 28 May 2026 07:36:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=159.226.251.81 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779953798; cv=none; b=VQRqMwobS8B0fqJnf5MFT4l8bNeRhhkJ9aITwZVP4/ztNZiVEUQYvt5DqKZZdRAdMw4z3sBChK3bmjlNzPYnkepP3wyxapy8pIZXOJyVxCgrzlt6bW6WWD9dJ4NLATYdYlwXZJPCyxp5X2rzIueouq0eCDf4G68tt2r27F2c2sE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779953798; c=relaxed/simple; bh=G+0SBHPfajvCnZMGxHvYX09QmzjENo0xCYn8VkdJW7M=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=GM9gAJRk91uTctv8q/Rr7ZUyt98WS5Tyvo9t0Zmq7KB7vV1M5Xsl9PJsUPArJhULMfJrvZxSo2iNTP0qzItdiWg4g6xBYUQepqHdhjb7GV43OW5grfhYpAqxoDFxhM8HcOuvILyN54vAfxxsl0m1wcrjGfoBwbMNDRceWnlBf3c= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=iscas.ac.cn; spf=pass smtp.mailfrom=iscas.ac.cn; arc=none smtp.client-ip=159.226.251.81 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=iscas.ac.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=iscas.ac.cn Received: from dfae2b116770.home.arpa (unknown [36.110.52.2]) by APP-03 (Coremail) with SMTP id rQCowACXsdh78BdqsP6tEg--.9382S2; Thu, 28 May 2026 15:36:27 +0800 (CST) From: Wentao Liang To: "David S . Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Cc: Simon Horman , Kuniyuki Iwashima , Kees Cook , Feng Yang , Wentao Liang , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH] netlink: fix skb refcount leak when dump start fails Date: Thu, 28 May 2026 07:36:14 +0000 Message-Id: <20260528073614.1169858-1-vulab@iscas.ac.cn> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: rQCowACXsdh78BdqsP6tEg--.9382S2 X-Coremail-Antispam: 1UD129KBjvJXoW7Ww4UCF4UJr4xCw1fGFW7Arb_yoW8JFWxpF W5KrW5trW5trWIqanrAF4rXFy7Z3WYqr45GryFkan7Ar1rG34jyF48uFZIvr43ZrZ5Kwnr XFnrKF4Y9rs8ZFJanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUU9j14x267AKxVW8JVW5JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26r4j6ryUM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4j 6F4UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I0E14v26rxl6s 0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xII jxv20xvE14v26r106r15McIj6I8E87Iv67AKxVW8JVWxJwAm72CE4IkC6x0Yz7v_Jr0_Gr 1lF7xvr2IYc2Ij64vIr41lF7I21c0EjII2zVCS5cI20VAGYxC7M4IIrI8v6xkF7I0E8cxa n2IY04v7MxkF7I0En4kS14v26r1q6r43MxAIw28IcxkI7VAKI48JMxC20s026xCaFVCjc4 AY6r1j6r4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE 17CEb7AF67AKxVWUtVW8ZwCIc40Y0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1j6r1xMI IF0xvE2Ix0cI8IcVCY1x0267AKxVW8JVWxJwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4l IxAIcVC2z280aVAFwI0_Jr0_Gr1lIxAIcVC2z280aVCY1x0267AKxVW8JVW8JrUvcSsGvf C2KfnxnUUI43ZEXa7VUbHa0JUUUUU== X-CM-SenderInfo: pyxotu46lvutnvoduhdfq/1tbiCREBA2oXzkBytQAAsu Content-Type: text/plain; charset="utf-8" __netlink_dump_start() takes an extra reference on the received skb via refcount_inc(&skb->users) before storing it in cb->skb for the dump callback to consume. If the subsequent netlink_dump() call fails (line 2440), the dump was never started so the completion callback that would normally release cb->skb will never be invoked. In this case, the function returns the error directly without calling kfree_skb(skb) to release the extra reference taken at entry. Add kfree_skb(skb) before returning when netlink_dump() fails, so the skb reference is properly released. Fixes: b44d211e166b ("netlink: handle errors from netlink_dump()") Cc: stable@vger.kernel.org Signed-off-by: Wentao Liang --- net/netlink/af_netlink.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 2aeb0680807d..d904c1aad35d 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -2441,8 +2441,10 @@ int __netlink_dump_start(struct sock *ssk, struct sk= _buff *skb, =20 sock_put(sk); =20 - if (ret) + if (ret) { + kfree_skb(skb); return ret; + } =20 /* We successfully started a dump, by returning -EINTR we * signal not to send ACK even if it was requested. --=20 2.34.1