6.1-stable review patch. If anyone has any objections, please let me know.
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From: Jakub Kicinski kuba@kernel.org
commit 7663d522099ecc464512164e660bc771b2ff7b64 upstream.
It's currently possible to create an altname conflicting with an altname or real name of another device by creating it in another netns and moving it over:
[ ~]$ ip link add dev eth0 type dummy
[ ~]$ ip netns add test [ ~]$ ip -netns test link add dev ethX netns test type dummy [ ~]$ ip -netns test link property add dev ethX altname eth0 [ ~]$ ip -netns test link set dev ethX netns 1
[ ~]$ ip link ... 3: eth0: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000 link/ether 02:40:88:62:ec:b8 brd ff:ff:ff:ff:ff:ff ... 5: ethX: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000 link/ether 26:b7:28:78:38:0f brd ff:ff:ff:ff:ff:ff altname eth0
Create a macro for walking the altnames, this hopefully makes it clearer that the list we walk contains only altnames. Which is otherwise not entirely intuitive.
Fixes: 36fbf1e52bd3 ("net: rtnetlink: add linkprop commands to add and delete alternative ifnames") Reviewed-by: Jiri Pirko jiri@nvidia.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/core/dev.c | 9 ++++++++- net/core/dev.h | 3 +++ 2 files changed, 11 insertions(+), 1 deletion(-)
--- a/net/core/dev.c +++ b/net/core/dev.c @@ -1054,7 +1054,8 @@ static int __dev_alloc_name(struct net *
for_each_netdev(net, d) { struct netdev_name_node *name_node; - list_for_each_entry(name_node, &d->name_node->list, list) { + + netdev_for_each_altname(d, name_node) { if (!sscanf(name_node->name, name, &i)) continue; if (i < 0 || i >= max_netdevices) @@ -10949,6 +10950,7 @@ EXPORT_SYMBOL(unregister_netdev); int __dev_change_net_namespace(struct net_device *dev, struct net *net, const char *pat, int new_ifindex) { + struct netdev_name_node *name_node; struct net *net_old = dev_net(dev); char new_name[IFNAMSIZ] = {}; int err, new_nsid; @@ -10981,6 +10983,11 @@ int __dev_change_net_namespace(struct ne if (err < 0) goto out; } + /* Check that none of the altnames conflicts. */ + err = -EEXIST; + netdev_for_each_altname(dev, name_node) + if (netdev_name_in_use(net, name_node->name)) + goto out;
/* Check that new_ifindex isn't used yet. */ err = -EBUSY; --- a/net/core/dev.h +++ b/net/core/dev.h @@ -61,6 +61,9 @@ struct netdev_name_node { int netdev_get_name(struct net *net, char *name, int ifindex); int dev_change_name(struct net_device *dev, const char *newname);
+#define netdev_for_each_altname(dev, namenode) \ + list_for_each_entry((namenode), &(dev)->name_node->list, list) + int netdev_name_node_alt_create(struct net_device *dev, const char *name); int netdev_name_node_alt_destroy(struct net_device *dev, const char *name);