Commit 6e331f4c authored Jan 09, 2013 by Stefan Hajnoczi Committed by David S. Miller Jan 10, 2013

tuntap: refuse to re-attach to different tun_struct



Multiqueue tun devices support detaching a tun_file from its tun_struct
and re-attaching at a later point in time.  This allows users to disable
a specific queue temporarily.

ioctl(TUNSETIFF) allows the user to specify the network interface to
attach by name.  This means the user can attempt to attach to interface
"B" after detaching from interface "A".

The driver is not designed to support this so check we are re-attaching
to the right tun_struct.  Failure to do so may lead to oops.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 21caa662

drivers/net/tun.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -491,6 +491,8 @@ static int tun_attach(struct tun_struct tun, struct file file)
		err = -EINVAL;
		if (rcu_dereference_protected(tfile->tun, lockdep_rtnl_is_held()))
		goto out;
		if (tfile->detached && tun != tfile->detached)
		goto out;

		err = -EBUSY;
		if (!(tun->flags & TUN_TAP_MQ) && tun->numqueues == 1)

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