[PATCH net-next] vlan: take link netns into account in vlan_newlink()

[PATCH net-next] vlan: take link netns into account in vlan_newlink()

[Nicolas Dichtel]

When IFLA_LINK_NETNSID is set, the ifindex from IFLA_LINK comes from another
netns.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
---
 net/8021q/vlan_netlink.c | 13 ++++++++++++-
 net/core/net_namespace.c |  1 +
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/net/8021q/vlan_netlink.c b/net/8021q/vlan_netlink.c
index c92b52f37d38..e7875c7f3cb4 100644
--- a/net/8021q/vlan_netlink.c
+++ b/net/8021q/vlan_netlink.c
@@ -118,6 +118,7 @@ static int vlan_newlink(struct net *src_net, struct net_device *dev,
 {
 	struct vlan_dev_priv *vlan = vlan_dev_priv(dev);
 	struct net_device *real_dev;
+	struct net *link_net;
 	__be16 proto;
 	int err;
 
@@ -126,7 +127,17 @@ static int vlan_newlink(struct net *src_net, struct net_device *dev,
 
 	if (!tb[IFLA_LINK])
 		return -EINVAL;
-	real_dev = __dev_get_by_index(src_net, nla_get_u32(tb[IFLA_LINK]));
+	if (tb[IFLA_LINK_NETNSID]) {
+		int id = nla_get_s32(tb[IFLA_LINK_NETNSID]);
+
+		link_net = get_net_ns_by_id(src_net, id);
+		if (!link_net)
+			return -EINVAL;
+	} else {
+		link_net = get_net(src_net);
+	}
+	real_dev = __dev_get_by_index(link_net, nla_get_u32(tb[IFLA_LINK]));
+	put_net(link_net);
 	if (!real_dev)
 		return -ENODEV;
 
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index b7bde551ef76..8e24f974c665 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -219,6 +219,7 @@ struct net *get_net_ns_by_id(struct net *net, int id)
 
 	return peer;
 }
+EXPORT_SYMBOL(get_net_ns_by_id);
 
 /*
  * setup_net runs the initializers for the network namespace object.
-- 
2.2.2

Re: [PATCH net-next] vlan: take link netns into account in vlan_newlink()

[Nicolas Dichtel]

Le 26/01/2015 10:44, Nicolas Dichtel a écrit :
> When IFLA_LINK_NETNSID is set, the ifindex from IFLA_LINK comes from another
> netns.
>
> Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Please, discard this patch. It's not the right fix.
I will send an update later.

[PATCH net-next v2] rtnetlink: pass link_net to the newlink handler

[Nicolas Dichtel]

When IFLA_LINK_NETNSID is used, the netdevice should be built in this link netns
and moved at the end to another netns (pointed by the socket netns or
IFLA_NET_NS_[PID|FD]).

Existing user of the newlink handler will use the netns argument (src_net) to
find a link netdevice or to check some other information into the link netns.
For example, to find a netdevice, two information are required: an ifindex
(usually from IFLA_LINK) and a netns (this link netns).

Note: when using IFLA_LINK_NETNSID and IFLA_NET_NS_[PID|FD], a user may create a
netdevice that stands in netnsX and with its link part in netnsY, by sending a
rtnl message from netnsZ.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
---

v2: instead of patching each subsystem, pass the right netns to
    the newlink handler

 net/core/rtnetlink.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 07447d1665e6..fedd7ab4085a 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -2148,7 +2148,7 @@ replay:
 		dev->ifindex = ifm->ifi_index;
 
 		if (ops->newlink) {
-			err = ops->newlink(net, dev, tb, data);
+			err = ops->newlink(link_net ? : net, dev, tb, data);
 			/* Drivers should call free_netdev() in ->destructor
 			 * and unregister it on failure after registration
 			 * so that device could be finally freed in rtnl_unlock.
-- 
2.2.2

Re: [PATCH net-next v2] rtnetlink: pass link_net to the newlink handler

[David Miller]

From: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Date: Tue, 27 Jan 2015 11:13:08 +0100

> When IFLA_LINK_NETNSID is used, the netdevice should be built in this link netns
> and moved at the end to another netns (pointed by the socket netns or
> IFLA_NET_NS_[PID|FD]).
> 
> Existing user of the newlink handler will use the netns argument (src_net) to
> find a link netdevice or to check some other information into the link netns.
> For example, to find a netdevice, two information are required: an ifindex
> (usually from IFLA_LINK) and a netns (this link netns).
> 
> Note: when using IFLA_LINK_NETNSID and IFLA_NET_NS_[PID|FD], a user may create a
> netdevice that stands in netnsX and with its link part in netnsY, by sending a
> rtnl message from netnsZ.
> 
> Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>

Applied, thanks.