linux-kernel - [PATCH v4 9/9] net: fix sysfs permssions when device changes network namespace

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Message-Id: <20200224172110.4121492-10-christian.brauner@ubuntu.com>
Date:   Mon, 24 Feb 2020 18:21:10 +0100
From:   Christian Brauner <christian.brauner@...ntu.com>
To:     "David S. Miller" <davem@...emloft.net>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-kernel@...r.kernel.org, netdev@...r.kernel.org
Cc:     "Rafael J. Wysocki" <rafael@...nel.org>,
        Pavel Machek <pavel@....cz>, Jakub Kicinski <kuba@...nel.org>,
        Eric Dumazet <edumazet@...gle.com>,
        Stephen Hemminger <stephen@...workplumber.org>,
        linux-pm@...r.kernel.org,
        Christian Brauner <christian.brauner@...ntu.com>
Subject: [PATCH v4 9/9] net: fix sysfs permssions when device changes network namespace

Now that we moved all the helpers in place and make use netdev_change_owner()
to fixup the permissions when moving network devices between network
namespaces.

Signed-off-by: Christian Brauner <christian.brauner@...ntu.com>
---
/* v2 */
unchanged

/* v3 */
unchanged

/* v4 */
unchanged
---
 net/core/dev.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index a69e8bd7ed74..0f9c4684fcbd 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -10016,6 +10016,7 @@ EXPORT_SYMBOL(unregister_netdev);
 
 int dev_change_net_namespace(struct net_device *dev, struct net *net, const char *pat)
 {
+	struct net *net_old = dev_net(dev);
 	int err, new_nsid, new_ifindex;
 
 	ASSERT_RTNL();
@@ -10031,7 +10032,7 @@ int dev_change_net_namespace(struct net_device *dev, struct net *net, const char
 
 	/* Get out if there is nothing todo */
 	err = 0;
-	if (net_eq(dev_net(dev), net))
+	if (net_eq(net_old, net))
 		goto out;
 
 	/* Pick the destination device name, and ensure
@@ -10107,6 +10108,12 @@ int dev_change_net_namespace(struct net_device *dev, struct net *net, const char
 	err = device_rename(&dev->dev, dev->name);
 	WARN_ON(err);
 
+	/* Adapt owner in case owning user namespace of target network
+	 * namespace is different from the original one.
+	 */
+	err = netdev_change_owner(dev, net_old, net);
+	WARN_ON(err);
+
 	/* Add the device back in the hashes */
 	list_netdevice(dev);
 
-- 
2.25.1