6.5-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jakub Kicinski <kuba@xxxxxxxxxx>
commit 311cca40661f428b7aa114fb5af578cfdbe3e8b6 upstream.
dev_get_valid_name() overwrites the netdev's name on success.
This makes it hard to use in prepare-commit-like fashion,
where we do validation first, and "commit" to the change
later.
Factor out a helper which lets us save the new name to a buffer.
Use it to fix the problem of notification on netns move having
incorrect name:
5: eth0: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN group default
link/ether be:4d:58:f9:d5:40 brd ff:ff:ff:ff:ff:ff
6: eth1: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN group default
link/ether 1e:4a:34:36:e3:cd brd ff:ff:ff:ff:ff:ff
[ ~]# ip link set dev eth0 netns 1 name eth1
ip monitor inside netns:
Deleted inet eth0
Deleted inet6 eth0
Deleted 5: eth1: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN group default
link/ether be:4d:58:f9:d5:40 brd ff:ff:ff:ff:ff:ff new-netnsid 0 new-ifindex 7
Name is reported as eth1 in old netns for ifindex 5, already renamed.
Fixes: d90310243fd7 ("net: device name allocation cleanups")
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Reviewed-by: Jiri Pirko <jiri@xxxxxxxxxx>
Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/core/dev.c | 44 +++++++++++++++++++++++++++++++-------------
1 file changed, 31 insertions(+), 13 deletions(-)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1116,6 +1116,26 @@ static int __dev_alloc_name(struct net *
return -ENFILE;
}
+static int dev_prep_valid_name(struct net *net, struct net_device *dev,
+ const char *want_name, char *out_name)
+{
+ int ret;
+
+ if (!dev_valid_name(want_name))
+ return -EINVAL;
+
+ if (strchr(want_name, '%')) {
+ ret = __dev_alloc_name(net, want_name, out_name);
+ return ret < 0 ? ret : 0;
+ } else if (netdev_name_in_use(net, want_name)) {
+ return -EEXIST;
+ } else if (out_name != want_name) {
+ strscpy(out_name, want_name, IFNAMSIZ);
+ }
+
+ return 0;
+}
+
static int dev_alloc_name_ns(struct net *net,
struct net_device *dev,
const char *name)
@@ -1153,19 +1173,13 @@ EXPORT_SYMBOL(dev_alloc_name);
static int dev_get_valid_name(struct net *net, struct net_device *dev,
const char *name)
{
- BUG_ON(!net);
-
- if (!dev_valid_name(name))
- return -EINVAL;
-
- if (strchr(name, '%'))
- return dev_alloc_name_ns(net, dev, name);
- else if (netdev_name_in_use(net, name))
- return -EEXIST;
- else if (dev->name != name)
- strscpy(dev->name, name, IFNAMSIZ);
+ char buf[IFNAMSIZ];
+ int ret;
- return 0;
+ ret = dev_prep_valid_name(net, dev, name, buf);
+ if (ret >= 0)
+ strscpy(dev->name, buf, IFNAMSIZ);
+ return ret;
}
/**
@@ -10955,6 +10969,7 @@ int __dev_change_net_namespace(struct ne
const char *pat, int new_ifindex)
{
struct net *net_old = dev_net(dev);
+ char new_name[IFNAMSIZ] = {};
int err, new_nsid;
ASSERT_RTNL();
@@ -10981,7 +10996,7 @@ int __dev_change_net_namespace(struct ne
/* We get here if we can't use the current device name */
if (!pat)
goto out;
- err = dev_get_valid_name(net, dev, pat);
+ err = dev_prep_valid_name(net, dev, pat, new_name);
if (err < 0)
goto out;
}
@@ -11049,6 +11064,9 @@ int __dev_change_net_namespace(struct ne
kobject_uevent(&dev->dev.kobj, KOBJ_ADD);
netdev_adjacent_add_links(dev);
+ if (new_name[0]) /* Rename the netdev to prepared name */
+ strscpy(dev->name, new_name, IFNAMSIZ);
+
/* Fixup kobjects */
err = device_rename(&dev->dev, dev->name);
WARN_ON(err);
