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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Pavel Skripkin <paskripkin@gmail.com>,
        "David S. Miller" <davem@davemloft.net>
Subject: [PATCH 5.10 110/125] net: fddi: fix UAF in fza_probe
Date:   Thu, 22 Jul 2021 18:31:41 +0200
Message-Id: <20210722155628.366281453@linuxfoundation.org>
In-Reply-To: <20210722155624.672583740@linuxfoundation.org>
References: <20210722155624.672583740@linuxfoundation.org>
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From: Pavel Skripkin <paskripkin@gmail.com>

commit deb7178eb940e2c5caca1b1db084a69b2e59b4c9 upstream.

fp is netdev private data and it cannot be
used after free_netdev() call. Using fp after free_netdev()
can cause UAF bug. Fix it by moving free_netdev() after error message.

Fixes: 61414f5ec983 ("FDDI: defza: Add support for DEC FDDIcontroller 700
TURBOchannel adapter")
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/fddi/defza.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

--- a/drivers/net/fddi/defza.c
+++ b/drivers/net/fddi/defza.c
@@ -1504,9 +1504,8 @@ err_out_resource:
 	release_mem_region(start, len);
 
 err_out_kfree:
-	free_netdev(dev);
-
 	pr_err("%s: initialization failure, aborting!\n", fp->name);
+	free_netdev(dev);
 	return ret;
 }