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From: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
To: Xiao Liang <shaw.leon@gmail.com>,
	 Willem de Bruijn <willemdebruijn.kernel@gmail.com>,
	 Jason Wang <jasowangio@gmail.com>
Cc: netdev@vger.kernel.org
Subject: Re: [PATCH net] tun: drop batched packets while the device is down
Date: Tue, 27 Oct 2026 10:13:27 -0400	[thread overview]
Message-ID: <willemdebruijn.kernel.979ea775ab87@gmail.com> (raw)
In-Reply-To: <20261027101830.85327-1-shaw.leon@gmail.com>

Xiao Liang wrote:
> tun_sendmsg() handles TUN_MSG_PTR batches from vhost-net by calling
> tun_xdp_one() instead of tun_get_user(). But this path does not check
> IFF_UP, allowing packets from a guest to be injected into the host
> receive path while the device is administratively down.
> 
> Check IFF_UP in tun_xdp_one() before running XDP or building an skb.
> Drop the packet when the device is down, matching tun_get_user().
> 
> Fixes: 043d222f93ab ("tuntap: accept an array of XDP buffs through sendmsg()")
> Signed-off-by: Xiao Liang <shaw.leon@gmail.com>

Reviewed-by: Willem de Bruijn <willemb@google.com>



      parent reply	other threads:[~2026-10-27 14:13 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-10-27 10:18 [PATCH net] tun: drop batched packets while the device is down Xiao Liang
2026-10-27 10:21 ` netdev-bot+sinfo
2026-10-27 14:13 ` Willem de Bruijn [this message]

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