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Message-ID: <ZS41+WxrRVqq9BgL@nanopsycho> Date: Tue, 17 Oct 2023 09:21:29 +0200 From: Jiri Pirko <jiri@...nulli.us> To: Jakub Kicinski <kuba@...nel.org> Cc: davem@...emloft.net, netdev@...r.kernel.org, edumazet@...gle.com, pabeni@...hat.com, gnault@...hat.com, liuhangbin@...il.com, lucien.xin@...il.com Subject: Re: [PATCH net 2/5] net: check for altname conflicts when changing netdev's netns Mon, Oct 16, 2023 at 10:16:54PM CEST, kuba@...nel.org wrote: >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") >Signed-off-by: Jakub Kicinski <kuba@...nel.org> >--- >CC: gnault@...hat.com >CC: liuhangbin@...il.com >CC: lucien.xin@...il.com >CC: jiri@...nulli.us >--- > net/core/dev.c | 9 ++++++++- > net/core/dev.h | 3 +++ > 2 files changed, 11 insertions(+), 1 deletion(-) > >diff --git a/net/core/dev.c b/net/core/dev.c >index b08031957ffe..f4fa2692cf6d 100644 >--- a/net/core/dev.c >+++ b/net/core/dev.c >@@ -1086,7 +1086,8 @@ static int __dev_alloc_name(struct net *net, const char *name, char *buf) > > 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) { Well, cleaner would be to do this in a separate patch and the fix itself too. One way or another, code looks fine. Reviewed-by: Jiri Pirko <jiri@...dia.com> Thanks! > if (!sscanf(name_node->name, name, &i)) > continue; > if (i < 0 || i >= max_netdevices) >@@ -11047,6 +11048,7 @@ 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; >@@ -11079,6 +11081,11 @@ int __dev_change_net_namespace(struct net_device *dev, struct net *net, > 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. */ > if (new_ifindex) { >diff --git a/net/core/dev.h b/net/core/dev.h >index e075e198092c..d093be175bd0 100644 >--- a/net/core/dev.h >+++ b/net/core/dev.h >@@ -62,6 +62,9 @@ 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, name_node) \ >+ list_for_each_entry((name_node), &(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); > >-- >2.41.0 >
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