From: Lin Ma <linma@zju.edu.cn>
To: netdev@vger.kernel.org
Cc: davem@davemloft.net, kuba@kernel.org, jirislaby@kernel.org,
gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org,
Lin Ma <linma@zju.edu.cn>
Subject: [PATCH v1] hamradio: remove needs_free_netdev to avoid UAF
Date: Thu, 11 Nov 2021 22:14:02 +0800 [thread overview]
Message-ID: <20211111141402.7551-1-linma@zju.edu.cn> (raw)
The former patch "defer 6pack kfree after unregister_netdev" reorders
the kfree of two buffer after the unregister_netdev to prevent the race
condition. It also adds free_netdev() function in sixpack_close(), which
is a direct copy from the similar code in mkiss_close().
However, in sixpack driver, the flag needs_free_netdev is set to true in
sp_setup(), hence the unregister_netdev() will free the netdev
automatically. Therefore, as the sp is netdev_priv, use-after-free
occurs.
This patch removes the needs_free_netdev = true and just let the
free_netdev to finish this deallocation task.
Signed-off-by: Lin Ma <linma@zju.edu.cn>
---
drivers/net/hamradio/6pack.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/drivers/net/hamradio/6pack.c b/drivers/net/hamradio/6pack.c
index bfdf89e54752..8a19a06b505d 100644
--- a/drivers/net/hamradio/6pack.c
+++ b/drivers/net/hamradio/6pack.c
@@ -306,7 +306,6 @@ static void sp_setup(struct net_device *dev)
{
/* Finish setting up the DEVICE info. */
dev->netdev_ops = &sp_netdev_ops;
- dev->needs_free_netdev = true;
dev->mtu = SIXP_MTU;
dev->hard_header_len = AX25_MAX_HEADER_LEN;
dev->header_ops = &ax25_header_ops;
--
2.33.1
next reply other threads:[~2021-11-11 14:14 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-11 14:14 Lin Ma [this message]
2021-11-12 1:55 ` [PATCH v1] hamradio: remove needs_free_netdev to avoid UAF Jakub Kicinski
2021-11-13 4:20 ` patchwork-bot+netdevbpf
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