Messages in this thread | | | From | Eric Dumazet <> | Date | Mon, 14 Mar 2022 10:24:01 -0700 | Subject | Re: [PATCH net-next 1/3] net: ipvlan: fix potential UAF problem for phy_dev |
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On Mon, Mar 14, 2022 at 3:54 AM Ziyang Xuan <william.xuanziyang@huawei.com> wrote: > > Add the reference operation to phy_dev of ipvlan to avoid > the potential UAF problem under the following known scenario: > > Someone module puts the NETDEV_UNREGISTER event handler to a > work, and phy_dev is accessed in the work handler. But when > the work is excuted, phy_dev has been destroyed because upper > ipvlan did not get reference to phy_dev correctly.
Can you name the module deferring NETDEV_UNREGISTER to a work queue ?
This sounds like a bug to me.
> > That likes as the scenario occurred by > commit 563bcbae3ba2 ("net: vlan: fix a UAF in vlan_dev_real_dev()").
Mentioning a commit that added a bug and many other commits trying to fix it is a bit unfortunate.
Can you instead add a Fixes: tag ?
Do you have a repro to trigger the bug ?
> > Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com> > --- > drivers/net/ipvlan/ipvlan_main.c | 13 +++++++++++++ > 1 file changed, 13 insertions(+) > > diff --git a/drivers/net/ipvlan/ipvlan_main.c b/drivers/net/ipvlan/ipvlan_main.c > index 696e245f6d00..dcdc01403f22 100644 > --- a/drivers/net/ipvlan/ipvlan_main.c > +++ b/drivers/net/ipvlan/ipvlan_main.c > @@ -158,6 +158,10 @@ static int ipvlan_init(struct net_device *dev) > } > port = ipvlan_port_get_rtnl(phy_dev); > port->count += 1; > + > + /* Get ipvlan's reference to phy_dev */ > + dev_hold(phy_dev); > + > return 0; > } > > @@ -665,6 +669,14 @@ void ipvlan_link_delete(struct net_device *dev, struct list_head *head) > } > EXPORT_SYMBOL_GPL(ipvlan_link_delete); > > +static void ipvlan_dev_free(struct net_device *dev) > +{ > + struct ipvl_dev *ipvlan = netdev_priv(dev); > + > + /* Get rid of the ipvlan's reference to phy_dev */ > + dev_put(ipvlan->phy_dev); > +} > + > void ipvlan_link_setup(struct net_device *dev) > { > ether_setup(dev); > @@ -674,6 +686,7 @@ void ipvlan_link_setup(struct net_device *dev) > dev->priv_flags |= IFF_UNICAST_FLT | IFF_NO_QUEUE; > dev->netdev_ops = &ipvlan_netdev_ops; > dev->needs_free_netdev = true; > + dev->priv_destructor = ipvlan_dev_free; > dev->header_ops = &ipvlan_header_ops; > dev->ethtool_ops = &ipvlan_ethtool_ops; > } > -- > 2.25.1 >
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