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net: ipmr, ip6mr: fix vif/tunnel failure race condition 

Since (at least) commit b17a7c179d ("[NET]: Do sysfs registration as
part of register_netdevice."), netdev_run_todo() deals only with
unregistration, so we don't need to do the rtnl_unlock/lock cycle to
finish registration when failing pimreg or dvmrp device creation. In
fact that opens a race condition where someone can delete the device
while rtnl is unlocked because it's fully registered. The problem gets
worse when netlink support is introduced as there are more points of entry
that can cause it and it also makes reusing that code correctly impossible.

Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Reviewed-by: Cong Wang <cwang@twopensource.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Nikolay Aleksandrov 2015-11-24 17:09:30 +01:00 committed by David S. Miller
parent 33c40e242c
commit fbdd29bfd2
2 changed files with 0 additions and 12 deletions
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8
net/ipv4/ipmr.c
View File

@ -441,10 +441,6 @@ struct net_device *ipmr_new_tunnel(struct net *net, struct vifctl *v)
return dev;
failure:
/* allow the register to be completed before unregistering. */
rtnl_unlock();
rtnl_lock();
unregister_netdevice(dev);
return NULL;
}
@ -540,10 +536,6 @@ static struct net_device *ipmr_reg_vif(struct net *net, struct mr_table *mrt)
return dev;
failure:
/* allow the register to be completed before unregistering. */
rtnl_unlock();
rtnl_lock();
unregister_netdevice(dev);
return NULL;
}

4
net/ipv6/ip6mr.c
View File

@ -765,10 +765,6 @@ static struct net_device *ip6mr_reg_vif(struct net *net, struct mr6_table *mrt)
return dev;
failure:
/* allow the register to be completed before unregistering. */
rtnl_unlock();
rtnl_lock();
unregister_netdevice(dev);
return NULL;
}