Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Pavel Skripkin <paskripkin@gmail.com>
To:     davem@davemloft.net, kuba@kernel.org, huangguobin4@huawei.com,
        jonas.jensen@gmail.com
Cc:     netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        Pavel Skripkin <paskripkin@gmail.com>
Subject: [PATCH] net: moxa: fix UAF in moxart_mac_probe
Date:   Fri,  9 Jul 2021 17:09:53 +0300
Message-Id: <20210709140953.1063-1-paskripkin@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

In case of netdev registration failure the code path will
jump to init_fail label:

init_fail:
	netdev_err(ndev, "init failed\n");
	moxart_mac_free_memory(ndev);
irq_map_fail:
	free_netdev(ndev);
	return ret;

So, there is no need to call free_netdev() before jumping
to error handling path, since it can cause UAF or double-free
bug.

Fixes: 6c821bd9edc9 ("net: Add MOXA ART SoCs ethernet driver")
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
---
 drivers/net/ethernet/moxa/moxart_ether.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/moxa/moxart_ether.c b/drivers/net/ethernet/moxa/moxart_ether.c
index b85733942053..b46bba9f4846 100644
--- a/drivers/net/ethernet/moxa/moxart_ether.c
+++ b/drivers/net/ethernet/moxa/moxart_ether.c
@@ -541,10 +541,8 @@ static int moxart_mac_probe(struct platform_device *pdev)
 	SET_NETDEV_DEV(ndev, &pdev->dev);
 
 	ret = register_netdev(ndev);
-	if (ret) {
-		free_netdev(ndev);
+	if (ret)
 		goto init_fail;
-	}
 
 	netdev_dbg(ndev, "%s: IRQ=%d address=%pM\n",
 		   __func__, ndev->irq, ndev->dev_addr);
-- 
2.32.0